Пропорции дома и крыши: Высота крыши по соотношению к ширине дома и как рассчитать высоту конька для различных типов кровли

Как самостоятельно рассчитывать оптимальный угол наклона крыши

При создании кровли уклон является одним из важнейших параметров, который учитывается в расчетах. Зависит он от материала для кровли, а также местного климата.

Угол наклона крыши является важнейшим параметром при возведении стропильной системы и расчете расхода кровельных материалов частного дома. Проектирование крыши – мероприятие весьма ответственное, которое следует доверить исключительно профессионалам, имеющим разрешение на проведение подобных работ.

Угол наклона крыши

• На что влияет уклон крыши
• В чем измеряется угол наклона крыши
• Правила расчета угла наклона кровли
• Определяем минимальный угол ската крыши в зависимости от кровельного материала
• Снеговые и ветровые нагрузки
• Примеры расчета

Однако в некоторых случаях, все предварительные расчеты можно сделать и самостоятельно, хотя бы для того, чтобы иметь представление о предполагаемом количестве материала и возможности реализации своих архитектурных идей. Из этой публикации вы узнаете, от чего зависит и как своими силами рассчитать угол наклона крыши, не прибегая к услугам дорогостоящих специалистов.

На что влияет уклон крыши

При самостоятельном возведении каркаса крыши большинство застройщиков руководствуется ее дизайном и назначением подкровельного пространства, что в корне неверно. На каркас крутых крыш практически не воздействует снеговая нагрузка, а это значит, что чисто теоретически можно сэкономить на сечении и шаге стропил. Однако ветер, оказывает наибольшее воздействие именно на кровли с крутыми скатами из-за их большой парусности, что уже на практике требует создания прочной стропильной системы.

Все это совершенно не значит, что пологие крыши лучше. На кровлях с малым уклоном снег будет задерживаться дольше, что создает внушительную нагрузку на стропильную систему. К тому же, угол ската крыши влияет на габариты чердачного помещения. Чем круче крыша – тем больше возможности у застройщика для обустройства жилой мансарды. Тем не менее не следует забывать о высокой стоимости конструкций с крутыми скатами, особенно в сравнении с пологими крышами. Сохранить объем чердачного пространства, не увеличивая высоту конька, поможет создание ломаной крыши.

Помимо снеговой и ветровой нагрузки на каркас оказывает влияние и вес кровельного пирога совместно с собственной массой стропильной системы. Если в кровле используются теплоизоляционные материалы, то и их вес учитывается при определении оптимального угла крыши.

В чем измеряется угол наклона крыши

Прежде всего, следует внести ясность в само понятие угол наклона. Данная величина – это угол, который образуется при пересечении горизонтальной плоскости (заложение) с плоскостью кровли. «Заложение» – это не что иное, как проекция ската крыши в горизонтальной плоскости.  

В справочной литературе и специализированных таблицах в качестве единицы измерения угла наклона крыши используются проценты. Уклон кровли в процентах показывает отношение высоты подъема кровли (Н) к заложению (L).

В двускатных крышах (L) – это величина, равная длине половины пролета. L в односкатных крышах равняется длине пролета.

Правила расчета угла наклона кровли

Допустим, L = 3 м, а Н = 1 м. В таком случае отношение будет выглядеть, как Н к L или 1:3. Это простейший пример, показывающий большие неудобства в определении угла уклона таким способом.

Для простоты вычислений применяется специальная формула расчета угла наклона крыши, которая выглядит следующим образом.

I = H/L где:

• I – тангенс уклона ската;
• Н – высота подъема кровли;
• L – значение заложения.

Используем данные из примера выше. L = 3 м и Н = 1 м. Тогда, формула расчета выглядит, как I = 1/3 = 0,33. Теперь, для перевода значения тангенса острого угла в проценты необходимо полученное значение умножить на 100. Исходя из этого, получаем: 0,33 х 100 = 33%

Как определить угол наклона крыши в градусах? Перевести проценты в градусы можно двумя простыми способами:

• воспользоваться онлайн-конвертором;
• воспользоваться таблицами, опубликованными в специализированной справочной литературе.

Первый способ весьма прост, но требует подключения к интернету. В сети представлено огромное количество ресурсов, предоставляющих возможность воспользоваться онлайн-конвертором.

Таблицы уклона крыши в градусах и процентах найти значительно сложнее, однако они проще в применении. Публикуем таблицу соотношения проценты-градусы.

Определяем минимальный угол ската крыши в зависимости от кровельного материала

Исходя из крутизны скатов, все крыши условно делятся на четыре типа:

• Высокие, с уклоном от 45 до 60°.
• Скатные, с углом наклона кровли от 30 до 45°.
• Пологие. Угол наклона скатов в таких конструкциях варьируется от 10 до 30°.
• Плоские с уклоном до 10°.

Подходя к возведению крыши, застройщик планирует использование определенного кровельного материала. Следует учитывать, что далеко не каждый материал может быть использован на крышах с различным уклоном.

Далее рассмотрим зависимость между наиболее распространенными кровельными материалами и минимально допустимым углом ската крыши:

1. Асбоцементный шифер — 9° или 16%. Соотношение высоты подъема кровли к заложению 1:6.
2. Ондулин — 5°. Соотношение сторон 1:11.
3. Минимальный угол наклона односкатной крыши из металлочерепицы составляет 14°.
4. Керамическая черепица — 11°. Соотношение 1:6.
5. Цементно-песчаная черепица — 34° или 67%. Соотношение высоты кровли к заложению 1:1,5.
6. Битумная черепица — 11°. Соотношение сторон 1:5.
7. Профнастил — 12° При меньшем уклоне необходимо провести обработку стыков герметизирующим средством.
8. Оцинковка и стальные листы требуют минимального уклона 17°.
9. Рулонные битумные материалы — 3°.
10. Наплавляемая кровля может быть использована в качестве покрытия крыши с уклоном 15%.

В проектировании крыш существует понятие – максимальный угол наклона скатов. Данное значение является критическим для использования конкретного материала. На рисунке ниже показаны минимальные и максимальные значения угла наклона крыши для некоторых распространенных кровельных материалов. Кроме этого, в последней колонке собраны данные о том, какой уклон ската чаще всего используется для данных материалов отечественными застройщиками.

Как видно из приведенной таблицы, между минимальным и максимальным углом наклона крыши весьма солидный разрыв.

Выбирая уклон из диапазона допустимых значений, следует руководствоваться исключительно эстетическими соображениями и расходом материала.

Снеговые и ветровые нагрузки

При проектировании кровли всегда учитываются снеговые и ветровые нагрузки на стропильную систему. Чем круче скаты, тем меньше снега на них задержится.

Для правильного вычисления необходимой прочности конструкции вводится поправочный коэффициент:

1. Для крыш с уклоном менее 25° применяется коэффициент равный 1.
2. Стропильные конструкции со скатами от 25 до 60° требуют применения коэффициента 0,7.
3. Кровли, выполненные с углом наклона скатов более 60°, не требуют применения коэффициента, так как снег на них практически не задерживается.

Для простоты вычислений используют карты, в которых отмечены средние значения снеговой нагрузки по регионам РФ.

Примеры расчета

Правила проведения расчетов просты: находим свой регион, определяем снеговую нагрузку, выделенную своим цветом, принимаем в расчет первое значение, умножаем на поправочный коэффициент исходя из предполагаемого угла уклона крыши. В качестве наглядного примера рассчитаем снеговую нагрузку для крыши дома в Норильске углом наклона скатов 35°. Итак, 560 кг/м2 умножаем на коэффициент 0,7. Получаем снеговую нагрузку для данного региона и конкретной конструкции кровли 392 кг/м2.

Для определения ветровых нагрузок также используются карты, в которых отмечены расчетные значения ветровых нагрузок по регионам.

Кроме этого, в расчетах следует учитывать:

1. Розу ветров, а конкретно – расположение дома на местности и относительно других строений.
2. Высоту постройки.

По типу расположения дома на местности, все строения можно разделить на три группы:

1. А – постройки, расположенные не открытой местности.
2. Б – Строения, расположенные в населенных пунктах с ветровой преградой не выше 10 м.
3. В – здания, находящиеся в населенных пунктах с ветровой преградой от 25 м.

В зависимости от зоны размещения и высоты строения при проектировании крыши вводятся поправочные коэффициенты, учитывающие ветровую нагрузку. Все факторы, влияющие на ветровую нагрузку, сведены в таблицу, по которой легко сделать расчет.

Например: для одноэтажного дома в Норильске ветровая нагрузка составит: 84 кг/м2 умноженная на коэффициент 0,5, соответствующий зоне «В», что составляет 42 кг/м2.

Помимо этого, учитываются аэродинамические нагрузки, воздействующие на стропильную систему и кровельный материал. В зависимости от направления ветра, нагрузку условно делят на зоны, которые предполагают различные поправочные коэффициенты.

Для обеспечения запаса прочности рекомендуется брать значения из наиболее нагруженных зон G и H. опубликовано econet.ru  

Подписывайтесь на наш канал Яндекс Дзен!

Если у вас возникли вопросы по этой теме, задайте их специалистам и читателям нашего проекта здесь.

P.S. И помните, всего лишь изменяя свое потребление — мы вместе изменяем мир! © econet

90000 SLOPING ROOF HOUSE 90001 90002 The roof is one of the most important components for building the house. It stands strong environmental factors, like rain, heat, and cold. Roofs are the shelter a house signifies. 90003 90002 Depending on their general shapes, roofs can be categorized into two predominant categories. One is the flat roof, and the other is the sloping roof. Flat roofs are common in commercial buildings and are easy to construct, compared to the sloped ones. 90003 90002 Sloping roofs are a common feature for residential properties.They also do not let water or other dirt accumulate by allowing them to simply slide off. 90003 90002 The houses with sloping roofs can take different shapes. The sloping roof house images from across the world show a variety of styles of sloping roofs. 90003 90002 The variety of shapes can be used, depending on the needs of the house-owners and their aesthetic preferences. 90003 90012 PITCH OF A ROOF 90013 90002 The most important part of any roof construction is the pitch of the roof. The pitch of the roof can be understood as the degree of the slant of the roof.90003 90002 90017 It is, essentially, the slope of the roof. Even flat roofs have the concept of a pitch. Technically, the pitch of a roof is expressed as 6/12, 6:12, 6 in 12 or even 6 over 12. 90018 90003 90002 To understand the notation, get a grasp of the concept of the pitch. The pitch of a roof is mathematically defined as the rise over run. 90003 90002 Basically, if the roof moved 12 inches horizontally inwards, and if the resulting increase in the height of the roof was 6 inches, then the pitch of the roof would be 6/12.90003 90002 The normal roof pitch for a house varies between 4/12 and 9/12. Anything below 4/12 is low slope, and anything above 9/12 is a steep slope. If roofs have a pitch lower than 2/12, then they are considered flat. 90003 90002 90027 90027 90003 90012 PITCH AND THE GOLDEN RATIO 90013 90002 An architect will always design a roof, remembering several things, including the materials to be used. The pitch of the roof will have a major effect on how a house will finally look. 90003 90002 Architects work in accordance to the wishes of the house owner when they design a house, but they also remember how palatable a roof would look when finally built.This is worked out by using experience and referring to the Golden Ratio. 90003 90002 90017 In simple words, a Golden Ratio provides a sense of equilibrium and balance to the construction. 90018 It is present everywhere and has been historically used by planners across history, including the construction of the Great Pyramids, the Taj Mahal, the Parthenon, and so on. 90003 90002 Therefore, whenever architects have a difficult time deciding the pitch of a roof, they refer to the ratio as a reference.The modern pitched roof houses also use the same concept. 90003 90002 Architects do not prefer pitches with an angle of 45 90043 o 90044. The reason for this is that it does not conform to the Golden Ratio. 90003 90012 SIGNIFICANCE OF PITCH 90013 90002 The pitch of the roof should be decided, remembering the climate of the region one lives in. 90003 90002 In areas that experience high snowfall, flatter roofs may not be a good choice, because the snow does not slide off, putting weight on the roof and creating a real problem, if the roof collapsed.90003 90002 Very steep roofs can also lead to an issue of the snow sliding over the sides and falling on the people below. 90003 90002 This is where an experienced architect can come in to suggest the ideal pitch for the house that is not only pleasing to the eye, but high on functionality too. 90003 90002 The slope of the roof can make or break a house. More information on the subject would be very helpful in keeping the costs in control and making the house safe and beautiful. 90003 90002 90017 The pitch of the roof affects how the house looks, but it also affects the amount and type of material that can be used.90018 90003 90002 So, if the roof is steep, it would require more material during construction. It should also be borne in mind that a lower pitch makes the slope flatter, which deposits more water on the roof. 90003 90002 This gives rise to another problem — leakage. As more water gets deposited, you will need a sturdier material to keep the roof intact. 90003 90002 This will definitely play a role, while choosing the material to cover the roof. Both tiles and shingles can be used for this purpose, but the material will vary.90003 90002 Clay and slate can be the roofing material for pitches of the order of a minimum of 35 90043 o 90044. If the roof must go below that angle, then it is better to go for concrete tiles, so the roof does not give away under the pressure of water. 90003 90002 If you have a high-pitched roof house plans, then consider shingles made of asphalt. Rubber membranes work well with flatter designs. These do not make a good option for sloped roofs because of two reasons. 90003 90002 One, such roofing material may pose a problem during installation on steeper slopes, and second, they do not make for an attractive look, when placed on a visibly sloping roof.90003 90012 DIFFERENT TYPES OF SLOPING ROOFS 90013 90002 Home owners should remember all these points while deciding on the roof they want to go for. There are many options to choose from, and each has its own pros and cons. Your decision should be as dependent on the aesthetic appeal of the roof as the weather conditions it will be exposed to. 90003 90002 The gable roof is the most popular style of sloped roof. It is the roof you see on the houses in the game of monopoly. The two rectangular, equal sized panels come together at a ridge to form the gable roof.It is a typical house roof you can find in many materials. 90003 90002 While designing such roofs, care should be taken to increase the angle of pitch to be in more alignment with the Golden Ratio. As is well-documented for Sir Edwin Lutyens, one of the greatest architects of all time, he avoided 45 90043 o 90044 pitches. He even called it the ‘ugly angle’. This is true for the planners of today. 90003 90002 They try to hit a pitch angle higher than 45 90043 o 90044. This decision not only adheres to the Golden ratio, but also makes the outer walls shorter, putting more emphasis on the roof.The final result is a pleasing and balanced look overall. 90003 90002 90091 90091 90003 90094 Salt Box Roof 90095 90002 The salt box roof adds a little extra to the otherwise humble roof. The style is almost the same as the gable roof, with the only difference being the length of one of the roof panels. One side of the roof is longer than the other, giving the house a distinct look. 90003 90002 These are used in independent houses, and the concept is a product of the twentieth century. This roof style also tries to achieve a steeper pitch for better results.90003 90094 Gambrel Roof 90095 90002 Gambrel roof is another popular option available for home owners. This has two identical roof panels on both sides; however, they are not straight like in other roof types. 90003 90002 The Gambrel roofs have two slopes — different roof pitches on the same house. The upper slope angle is wide, while the angle of the lower slope is steeper. This gives the Gambrel roofs their characteristic shape. 90003 90002 The roof has a Dutch origin and increases the room in the upper levels of the house, while retaining all the characteristics of a sloped roof.90003 90094 Mansard Roof 90095 90002 A Mansard is a roof with 4 sloping sides. It can be thought of as a four-sided Gambrel roof, which means there is a slope on all sides. It has a steeper angle on the lower slope and a wider angle for the upper. 90003 90002 The steeper lower level has windows that give more space for extra rooms. Given the shape of the Mansard roofs, the upper levels are only visible from a distance, not in close proximity. These roofs have a French origin, and the name means the attic space.It is also interchangeably used for a Gambrel roof in the European countries. 90003 90094 Pyramid Roof 90095 90002 The four-sided slopes are not the characteristic feature of only Mansard roofs; the Pyramid roofs also come with this feature. As the name suggests, these roofs are shaped like pyramids, a roof with four sloping sides. 90003 90002 These roofs are best-suited for smaller structures, like a farmhouse hut. These roofs are popular in the contemporary architecture, with many structures getting these roofs.The walls of these houses are symmetrical and easy to build. A lower degree pitch works best for such four-sided roofs. 90003 90002 They would work even better if the walls were smaller and the roof made for a significant part of the house. It is not only aesthetically pleasing, but also more energy efficient. 90121 Pictures of sloping roof houses make a site to behold. 90003 90002 They are beautiful and look royal. Choosing between flat or high-pitched roof houses depends on many factors, including the weather, cost, personal taste, and, to a lesser extent, the neighborhood.90003 90002 The twentieth century may have seen an onslaught of flatter roofs with the cost saving objective, but sloping roofs with huge functional benefits, have their share of takers — a pool expanding by the day. 90003.90000 Proportions 90001 90002 Proportion says that two ratios (or fractions) are equal. 90003 90004 Example: 90005 90002 90003 90002 90003 90002 So 90011 1-out-of-3 90012 is equal to 90011 2-out-of-6 90012 90003 90002 90003 90002 The ratios are the same, so they are in proportion. 90003 90004 Example: Rope 90005 90002 A rope’s 90011 length 90012 and 90011 weight 90012 are in proportion. 90003 90002 When 90011 20m 90012 of rope weighs 90011 1kg 90012, then: 90003 90034 90035 90011 40m 90012 of that rope weighs 90011 2kg 90012 90040 90035 90011 200m 90012 of that rope weighs 90011 10kg 90012 90040 90035 etc.90040 90049 90002 90003 90002 So: 90003 90002 90055 20 90056 90057 1 90058 = 90055 40 90056 90057 2 90058 90003 90004 Sizes 90005 90002 When shapes are «in proportion» their relative sizes are the same. 90003 90068 90069 90070 90002 Here we see that the ratios of head length to body length are the same in both drawings. 90003 90002 So they are 90011 proportional 90012. 90003 90002 Making the head too long or short would look bad! 90003 90079 90070 90079 90082 90083 90004 Example: International paper sizes (like A3, A4, A5, etc) all have the same proportions: 90005 90002 90003 90002 So any artwork or document can be resized to fit on any sheet.Very neat. 90003 90090 Working With Proportions 90091 90002 NOW, how do we use this? 90003 90004 Example: you want to draw the dog’s head … how long should it be? 90005 90002 90003 90002 Let us write the proportion with the help of the 10/20 ratio from above: 90003 90002 90055? 90056 90057 42 90058 = 90055 10 90056 90057 20 90058 90003 90002 Now we solve it using a special method: 90003 90002 90003 90002 Multiply across the known corners, 90115 then divide by the third number 90003 90002 And we get this: 90003 90002? = (42 × 10) / 20 90115 = 420/20 90115 = 90011 21 90012 90003 90002 So you should draw the head 90011 21 90012 long.90003 90002 90003 90090 Using Proportions to Solve Percents 90091 90002 A percent is actually a ratio! Saying «25%» is actually saying «25 per 100»: 90003 90002 25% = 90055 25 90056 90057 100 90058 90003 90002 We can use proportions to solve questions involving percents. 90003 90002 The trick is to put what we know into this form: 90003 90002 90055 Part 90056 90057 Whole 90058 = 90055 Percent 90056 90057 100 90058 90003 90002 90003 90004 Example: what is 25% of 160? 90005 90002 The percent is 25, the whole is 160, and we want to find the «part»: 90003 90002 90055 Part 90056 90057 160 90058 = 90055 25 90056 90057 100 90058 90003 90002 Multiply across the known corners, then divide by the third number: 90003 90002 90003 90002 Part = (160 × 25) / 100 90115 = 4000/100 90115 = 90011 40 90012 90003 90002 90011 Answer: 25% of 160 is 40.90012 90003 90002 90003 90002 Note: we could have also solved this by doing the divide first, like this: 90003 90002 Part = 160 × (25/100) 90115 = 160 × 0.25 90115 = 90011 40 90012 90003 90002 Either method works fine. 90003 90002 We can also find a Percent: 90003 90004 Example: what is $ 12 as a percent of $ 80? 90005 90002 Fill in what we know: 90003 90002 90055 $ 12 90056 90057 $ 80 90058 = 90055 Percent 90056 90057 100 90058 90003 90002 Multiply across the known corners, then divide by the third number.This time the known corners are top left and bottom right: 90003 90002 90003 90002 Percent = ($ 12 × 100) / $ 80 90115 = 1200/80 90115 = 90011 15% 90012 90003 90002 Answer: $ 12 is 90011 15% 90012 of $ 80 90003 90002 Or find the Whole: 90003 90004 Example: The sale price of a phone was $ 150, which was only 80% of normal price. What was the normal price? 90005 90002 Fill in what we know: 90003 90002 90055 $ 150 90056 90057 Whole 90058 = 90055 80 90056 90057 100 90058 90003 90002 Multiply across the known corners, then divide by the third number: 90003 90002 90003 90002 Whole = ($ 150 × 100) / 80 90115 = 15000/80 90115 = 90011 187.50 90012 90003 90002 Answer: the phone’s normal price was 90011 $ 187.50 90012 90003 90090 Using Proportions to Solve Triangles 90091 90002 We can use proportions to solve similar triangles. 90003 90004 Example: How tall is the Tree? 90005 90002 Sam tried using a ladder, tape measure, ropes and various other things, but still could not work out how tall the tree was. 90003 90002 90003 90002 But then Sam has a clever idea … similar triangles! 90003 90002 Sam measures a stick and its shadow (in meters), and also the shadow of the tree, and this is what he gets: 90003 90002 90003 90002 Now Sam makes a sketch of the triangles, and writes down the «Height to Length» ratio for both triangles: 90003 90002 90055 Height: 90056 90057 Shadow Length: 90058 90055 h 90056 90057 2.9 m 90058 = 90055 2.4 m 90056 90057 1.3 m 90058 90003 90002 Multiply across the known corners, then divide by the third number: 90003 90002 h = (2.9 × 2.4) / 1.3 90115 = 6.96 / 1.3 90115 = 90011 5.4 m 90012 (to nearest 0.1) 90003 90002 90011 Answer: the tree is 5.4 m tall. 90012 90003 90002 And he did not even need a ladder! 90003 90002 The «Height» could have been at the bottom, so long as it was on the bottom for BOTH ratios, like this: 90003 90002 90003 90002 Let us try the ratio of «Shadow Length to Height»: 90003 90002 90055 Shadow Length: 90056 90057 Height: 90058 90055 2.9 m 90056 90057 h 90058 = 90055 1.3 m 90056 90057 2.4 m 90058 90003 90002 Multiply across the known corners, then divide by the third number: 90003 90002 h = (2.9 × 2.4) / 1.3 90115 = 6.96 / 1.3 90115 = 90011 5.4 m 90012 (to nearest 0.1) 90003 90002 90011 It is the same calculation as before. 90012 90003 90090 A «Concrete» Example 90091 90002 Ratios can have 90011 more than two numbers 90012! 90003 90002 For example concrete is made by mixing cement, sand, stones and water.90003 90002 90003 90002 A typical mix of cement, sand and stones is written as a ratio, such as 1: 2: 6. 90003 90002 We can multiply all values ​​by the same amount and still have the same ratio. 90003 90349 10:20:60 is the same as 1: 2: 6 90003 90002 So when we use 10 buckets of cement, we should use 20 of sand and 60 of stones. 90003 90004 Example: you have just put 12 buckets of stones into a mixer, how much cement and how much sand should you add to make a 1: 2: 6 mix? 90005 90002 Let us lay it out in a table to make it clearer: 90003 90357 90358 90359 90360 90359 Cement 90360 90359 Sand 90360 90359 Stones 90360 90082 90358 90359 Ratio Needed: 90360 90070 1 90079 90070 2 90079 90070 6 90079 90082 90358 90359 You Have: 90360 90381 90079 90381 90079 90070 12 90079 90082 90083 90002 You have 12 buckets of stones but the ratio says 6.90003 90002 That is OK, you simply have twice as many stones as the number in the ratio … so you need twice as much of 90011 everything 90012 to keep the ratio. 90003 90002 Here is the solution: 90003 90357 90358 90359 90360 90359 Cement 90360 90359 Sand 90360 90359 Stones 90360 90082 90358 90359 Ratio Needed: 90360 90070 1 90079 90070 2 90079 90070 6 90079 90082 90358 90359 You Have: 90360 90381 2 90079 90381 4 90079 90070 12 90079 90082 90083 90002 And the ratio 2: 4: 12 is the same as 1: 2: 6 (because they show the same 90430 90011 relative 90012 90433 sizes) 90003 90002 So the answer is: add 2 buckets of Cement and 4 buckets of Sand.90430 (You will also need water and a lot of stirring ….) 90433 90003 90002 90430 Why are they the same ratio? 90433 90430 Well, the 90011 1: 2: 6 90012 ratio says to have 90433: 90003 90034 90035 90430 twice as much Sand as Cement (1: 2: 6) 90433 90040 90035 90430 6 times as much Stones as Cement (1: 2: 6) 90433 90040 90049 90002 90458 90430 In our mix we have: 90433 90003 90034 90035 90430 twice as much Sand as Cement (2: 4: 12) 90433 90040 90035 90430 6 times as much Stones as Cement (2: 4: 12) 90433 90040 90049 90002 90430 So it should be just right! 90433 90003 90002 That is the good thing about ratios.You can make the amounts bigger or smaller and so long as the 90011 relative 90012 sizes are the same then the ratio is the same. 90003 90002 90003 90002 90003 90002 90003 .90000 1.1 Rainwater harvesting from rooftop catchments 90001 90002 90003 90002 90003 90006 The application of an appropriate rainwater harvesting technology can make possible the utilization of rainwater as a valuable and, in many cases, necessary water resource. Rainwater harvesting has been practiced for more than 4, 000 years, and, in most developing countries, is becoming essential owing to the temporal and spatial variability of rainfall. Rainwater harvesting is necessary in areas having significant rainfall but lacking any kind of conventional, centralized government supply system, and also in areas where good quality fresh surface water or groundwater is lacking.90003 90006 Annual rainfall ranging from less than 500 to more than 1 500 mm can be found in most Latin American countries and the Caribbean. Very frequently most of the rain falls during a few months of the year, with little or no precipitation during the remaining months. There are countries in which the annual and regional distribution of rainfall also differ significantly. 90003 90006 For more than three centuries, rooftop catchments and cistern storage have been the basis of domestic water supply on many small islands in the Caribbean.During World War II, several airfields were also turned into catchments. Although the use of rooftop catchment systems has declined in some countries, it is estimated that more than 500 000 people in the Caribbean islands depend at least in part on such supplies. Further, large areas of some countries in Central and South America, such as Honduras, Brazil, and Paraguay, use rainwater harvesting as an important source of water supply for domestic purposes, especially in rural areas. 90003 90006 90013 Technical Description 90014 90003 90006 A rainwater harvesting system consists of three basic elements: a collection area, a conveyance system, and storage facilities.The collection area in most cases is the roof of a house or a building. The effective roof area and the material used in constructing the roof influence the efficiency of collection and the water quality. 90003 90006 A conveyance system usually consists of gutters or pipes that deliver rainwater falling on the rooftop to cisterns or other storage vessels. Both drainpipes and roof surfaces should be constructed of chemically inert materials such as wood, plastic, aluminum, or fiberglass, in order to avoid adverse effects on water quality.90003 90006 The water ultimately is stored in a storage tank or cistern, which should also be constructed of an inert material. Reinforced concrete, fiberglass, or stainless steel are suitable materials. Storage tanks may be constructed as part of the building, or may be built as a separate unit located some distance away from the building. Figure 1 shows a schematic of a rooftop catchment system in the Dominican Republic. 90003 90006 · All rainwater tank designs (see Figures 2a and 2b) should include as a minimum requirement: 90003 90024 — A solid secure cover 90025 — A coarse inlet filter 90025 — An overflow pipe 90025 — A manhole, sump, and drain to facilitate cleaning 90025 — An extraction system that does not contaminate the water; e.g., a tap or pump 90025 — A soakaway to prevent spilled water from forming puddles near the tank 90030 90006 Additional features might include: 90003 90024 — A device to indicate the amount of water in the tank 90025 — A sediment trap, tipping bucket, or other «foul flush» mechanism 90025 — A lock on the tap 90025 — A second sub-surface tank to provide water for livestock , etc. 90030 90006 · The following questions need to be considered in areas where a rainwater cistern system project is being considered, to establish whether or not rainwater catchment warrants further investigation: 90003 90024 — Is there a real need for an improved water supply? 90006 — Are present water supplies either distant or contaminated, or both? 90003 90006 — Do suitable roofs and / or other catchment surfaces exist in the community? 90003 90006 — Does rainfall exceed 400 mm per year? 90003 90006 — Does an improved water supply figure prominently in the community’s list of development priorities? 90003 90030 90006 · If the answer to these five questions is yes, it is a clear indication that rainwater collection might be a feasible water supply option.Further questions, however, also need to be considered: 90003 90024 — What alternative water sources are available in the community and how do these compare with the rooftop catchment system? 90006 — What are the economic, social, and environmental implications of the various water supply alternatives (eg, how able is the community to pay for water obtained from other sources; what is the potential within the community for income generating activities that can be used to develop alternative water sources; does the project threaten the livelihood of any community members, such as water vendors?) 90003 90006 — What efforts have been made, by either the community or an outside agency, to implement an improved water supply system in the past? (Lessons may be learned from the experiences of the previous projects.) 90003 90030 90006 · All catchment surfaces must be made of nontoxic material. Painted surfaces should be avoided if possible, or, if the use of paint is unavoidable, only nontoxic paint should be used (e.g., no lead-, chromium-, or zinc-based paints). Overhanging vegetation should also be avoided. 90003 90002 90013 90013 Figure 1: Schematic of a Typical Rainwater Catchment System. 90014 90014 90003 90002 90003 90024 Source: José Payero, Professor-Researcher, Department of Natural Resources, Higher Institute of Agriculture (ISA), Dominican Republic.90030 90006 90013 Extent of Use 90014 90003 90006 Rainwater harvesting is used extensively in Latin America and the Caribbean, mainly for domestic water supply and, in some cases, for agriculture and livestock supplies on a small scale. In Brazil and Argentina, rainwater harvesting is used in semi-arid regions. In Central American countries like Honduras (see case study in Part C, Chapter 5), Costa Rica, Guatemala, and El Salvador, rainwater harvesting using rooftop catchments is used extensively in rural areas.90003 90006 In Saint Lucia, storage tanks are constructed of a variety of materials, including steel drums (200 l), large polyethylene plastic tanks (1 300 to 2 300 l), and underground concrete cisterns (100 000 to 150 000 l). 90003 90006 The Turks and Caicos Islands have a number of government-built, public rainfall catchment systems. Government regulations make it mandatory that all developers construct a water cistern large enough to store 400 l / m 90079 2 90080 of roof area. 90003 90006 Rooftop and artificially constructed catchments, such as the one at the former United States naval base on Eleuthera, are commonplace in the Bahamas.One settlement (Whale Cay) has a piped distribution system based on water captured from rooftops. On New Providence, most of the older houses collect rainwater from rooftops and store it in cisterns with average capacities of 70 000 l. Industries also use rooftop rainwater, and a preliminary assessment has been made of using Nassau International Airport as a catchment. In multistoried apartment buildings and other areas serving large concentrations of people (such as hotels and restaurants), water supplies are supplemented by water from rooftop catchment cisterns.90003 90006 The Islas de la Bahía off the shores of Honduras meet a substantial portion of their potable water needs using rainwater from rooftop catchments. Similarly, rooftop catchments and cistern storage provide a significant water supply source for a small group of islands off the northern coast of Venezuela. 90003 90006 In a recent rural water-supply study, the continued use of rooftop and artificially constructed catchments was contemplated for those parts of rural Jamaica lacking access to river, spring, or well water sources.It is thought that more than 100 000 Jamaicans depend to a major extent on rainwater catchments. 90003 90006 90013 Operation and Maintenance 90014 90003 90002 90013 90013 Figure 2A: Schematic of a Cistern 90014 90014 90003 90002 90003 90024 Source: Walter Santos, Center for Training in Agricultural Development, Bureau of Water Resources, Comayagua, Honduras. 90030 90002 90013 90013 Figure 2B: Schematic of a Storage Tank Reservoir 90014 90014 90003 90002 90003 90024 Source: Walter Santos, Center for Training in Agricultural Development, Bureau of Water Resources, Comayagua, Honduras.90030 90006 Rainwater harvesting systems require few skills and little supervision to operate. Major concerns are the prevention of contamination of the tank during construction and while it is being replenished during a rainfall. Contamination of the water supply as a result of contact with certain materials can be avoided by the use of proper materials during construction of the system. For example, in Montserrat, where 95% of the houses in the medium to high density areas are roofed with oil-based bitumen shingles, consumers are strongly discouraged from using this source of supply for drinking purposes.Use of alternative roofing materials would have avoided this problem. The main sources of external contamination are pollution from the air, bird and animal droppings, and insects. Bacterial contamination may be minimized by keeping roof surfaces and drains clean but can not be completely eliminated. If the water is to be used for drinking purposes, filtration and chlorination or disinfection by other means (e.g., boiling) is necessary. The following maintenance guidelines should be considered in the operation of rainwater harvesting systems: 90003 90024 · A procedure for eliminating the «foul flush» after a long dry spell deserves particular attention.The first part of each rainfall should be diverted from the storage tank since this is most likely to contain undesirable materials which have accumulated on the roof and other surfaces between rainfalls. Generally, water captured during the first 10 minutes of rainfall during an event of average intensity is unfit for drinking purposes. The quantity of water lost by diverting this runoff is usually about 14l / m 90079 2 90080 of catchment area. 90006 · The storage tank should be checked and cleaned periodically.All tanks need cleaning; their designs should allow for this. Cleaning procedures consist of thorough scrubbing of the inner walls and floors. Use of a chlorine solution is recommended for cleaning, followed by thorough rinsing. 90003 90006 · Care should be taken to keep rainfall collection surfaces covered, to reduce the likelihood of frogs, lizards, mosquitoes, and other pests using the cistern as a breeding ground. Residents may prefer to take care to prevent such problems rather than have to take corrective actions, such as treating or removing water, at a later time.90003 90006 · Chlorination of the cisterns or storage tanks is necessary if the water is to be used for drinking and domestic uses. The Montserrat Island Water Authority constructed a non-conventional chlorination device with a rubber tube, plywood, a 1.2 m piece of PVC tubing, and a hose clip to chlorinate the water using chlorine tablets. 90003 90006 · Gutters and downpipes need to be periodically inspected and cleaned carefully. Periodic maintenance must also be carried out on any pumps used to lift water to selected areas in the house or building.More often than not, maintenance is done only when equipment breaks down. 90003 90006 · Community systems require the creation of a community organization to maintain them effectively. Similarly, households must establish a maintenance routine that will be carried out by family members. 90003 90030 90006 As has been noted, in some cases the rainwater is treated with chlorine tablets. However, in most places it is used without treatment. In such cases, residents are advised to boil the water before drinking.Where cistern users do not treat their water, the quality of the water may be assured through the installation of commercially available in-line charcoal filters or other water treatment devices. Community catchments require additional protections, including: 90003 90024 · Fencing of the paved catchment to prevent the entry of animals, primarily livestock such as goats, cows, donkeys, and pigs, that can affect water quality. 90006 · Cleaning the paved catchment of leaves and other vegetative matter.90003 90006 · Repairing large cracks in the paved catchment as a result of soil movement, earthquakes, or exposure to the elements. 90003 90006 · Maintaining water quality at a level where health risks are minimized. In many systems, this involves chlorination of the supplies at frequent intervals. 90003 90030 90006 Problems usually encountered in maintaining the system at an efficient level include the lack of availability of chemicals required for appropriate treatment and the lack of adequate funding.90003 90006 90013 Level of Involvement 90014 90003 90006 The level of governmental participation varies in the countries of Latin America and the Caribbean. In some Caribbean islands, governments regulate the design of rainwater harvesting systems. In the U.S. Virgin Islands, the law requires that provision be made in the construction of all new buildings for the capture and storage of rainfall coming into contact with their roofs. The law requires that roofs be guttered and that cisterns be constructed having a volume that depends on the size of the roof, the intended use of the structure, and the number of floors.For a typical single-level, residential building, the law requires that 400 1 of storage be provided for each m 90079 2 90080 of roof area. Cistern construction is further regulated by the Virgin Islands Building Code to insure the structural integrity of these cisterns, which usually form an integral part of building foundations. As of January 1, 1996, all new residences in Barbados are required to construct water storage facilities if the roof area or living area equals or exceeds 3 000 square feet.They will also be mandatory for all new commercial buildings with a roof area of ​​1 000 square feet or more. A rebate of $ 0.50 per gallon of installed tank capacity, up to the equivalent of 25% of the total roof area, will be given as an incentive by the Barbados Water Authority. 90003 90006 Cisterns are likely to continue to be a principal source of water for residences in several Caribbean islands. Even if mandatory requirements are removed, their use will remain widespread, as they provide a water supply that residents consider to be safe, sufficient, and inexpensive.90003 90006 90013 Costs 90014 90003 90006 The cost of this technology varies considerably depending on location, type of materials used, and degree of implementation. In Brazil, the cost of a 30m 90079 3 90080 cistern in rural areas of the Northeast is around $ 900 to $ 1 000, depending on the material used. In the U.S. Virgin Islands, costs as low as $ 2 to $ 5/1 000 1 are reported. Construction costs for underground cisterns can vary tremendously, based on the size and the amount of excavation required.In Saint Lucia, the average cost of a 1, 5001 plastic tank is $ 125. 90003 90006 In the Chaco region of Paraguay, two different types of cisterns have been used for rainwater harvesting: cisterns or storage tanks called 90159 aljibes, 90160 and cutwater cisterns called 90159 tajamares. 90160 The capital cost of a 30 m 90079 3 90080 cistern 90159 (aljibe) 90160 in Paraguay has been reported to be $ 2 000, while the construction of a 6 000 m 90079 3 90080 90159 tajamar, 90160 including windmill-driven pumps and distribution piping , has been estimated at $ 8 400.90003 90006 90013 Effectiveness of the Technology 90014 90003 90006 Rainfall harvesting technology has proved to be very effective throughout several Latin American countries and most of the Caribbean islands, where cisterns are the principal source of water for residences. Cisterns are capable of providing a sufficient supply for most domestic applications. The use of rainwater is very effective in lessening the demand on the public water supply system in the British Virgin Islands.It also provides a convenient buffer in times of emergency or shortfall in the public water supply. Also, because of the hilly or mountainous nature of the terrain in the majority of the British Virgin Islands, combined with dispersed housing patterns, rainfall harvesting appears to be the most practical way of providing a water supply to some residents. In many countries it is very costly, and in some cases not economically feasible, to extend the public water supply to all areas, where houses are isolated from one another or in mountainous areas.90003 90006 Steep galvanized iron roofs have been found to be relatively efficient rainwater collectors, while flat concrete roofs, though highly valued as protection from hurricanes, are very inefficient. Rooftop catchment efficiencies range from 70% to 90%. It has been estimated that 1 cm of rain on 100 m 90079 2 90080 of roof yields 10 0001. More commonly, rooftop catchment yield is estimated to be 75% of actual rainfall on the catchment area, after accounting for losses due to evaporation during periods when short, light showers are interspersed with periods of prolonged sunshine.Likewise, at the other extreme, the roof gutters and downpipes generally can not cope with rainfalls of high intensity, and excess water runs off the roof to waste during these periods. 90003 90006 90013 Suitability 90014 90003 90006 This technology is suitable for use in all areas as a means of augmenting the amount of water available. It is most useful in arid and semi-arid areas where other sources of water are scarce. 90003 90006 90013 Advantages 90014 90003 90024 · Rainwater harvesting provides a source of water at the point where it is needed.It is owner operated and managed. 90006 · It provides an essential reserve in times of emergency and / or breakdown of public water supply systems, particularly during natural disasters. 90003 90006 · The construction of a rooftop rainwater catchment system is simple, and local people can easily be trained to build one, minimizing its cost. 90003 90006 · The technology is flexible. The systems can be built to meet almost any requirements. Poor households can start with a single small tank and add more when they can afford them.90003 90006 · It can improve the engineering of building foundations when cisterns are built as part of the substructure of the buildings, as in the case of mandatory cisterns. 90003 90006 · The physical and chemical properties of rainwater may be superior to those of groundwater or surface waters that may have been subjected to pollution, sometimes from unknown sources. 90003 90006 · Running costs are low. 90003 90006 · Construction, operation, and maintenance are not labor-intensive.90003 90030 90006 90013 Disadvantages 90014 90003 90024 · The success of rainfall harvesting depends upon the frequency and amount of rainfall; therefore, it is not a dependable water source in times of dry weather or prolonged drought. 90006 · Low storage capacities will limit rainwater harvesting so that the system may not be able to provide water in a low rainfall period. Increased storage capacities add to construction and operating costs and may make the technology economically unfeasible, unless it is subsidized by government.90003 90006 · Leakage from cisterns can cause the deterioration of load bearing slopes. 90003 90006 · Cisterns and storage tanks can be unsafe for small children if proper access protection is not provided. 90003 90006 · Possible contamination of water may result from animal wastes and vegetable matter. 90003 90006 · Where treatment of the water prior to potable use is infrequent, due to a lack of adequate resources or knowledge, health risks may result; further, cisterns can be a breeding ground for mosquitoes.90003 90006 · Rainfall harvesting systems increase construction costs and may have an adverse effect on home ownership. Systems may add 30% to 40% to the cost of a building. 90003 90006 · Rainfall harvesting systems may reduce revenues to public utilities. 90003 90030 90006 90013 Cultural Acceptability 90014 90003 90006 In Latin America and the Caribbean, it has been found that projects which involved the local community from the outset in the planning, implementation, and maintenance have the best chance of enduring and expanding.Those projects which have been predominantly run by local people have had a much higher rate of success than those operated by people foreign to an area, and those to which the community has contributed ideas, funds, and labor have had a greater rate of success than those externally planned, funded, and built. Successful rainwater harvesting projects are generally associated with communities that consider water supply a priority. 90003 90006 In the Caribbean, attitudes toward the use of rainwater for domestic consumption differ.Some people, who depend on rainwater as their only source of supply, use it for all household purposes, from drinking and cooking to washing and other domestic uses. Other people, who have access to both rainwater and a public water supply, use rainwater selectively, for drinking or gardening or flushing toilets, and use the public water supply for other purposes. These varying attitudes are related to the level of education of the users as well as to their traditional preferences. Different sectors of the society need to be informed about the advantages of harvesting rainwater and the related safety aspects of its use, including the threat of mosquito problems and other public health concerns.90003 90006 90013 Further Development of the Technology 90014 90003 90006 There is a need for the water quality aspects of rainwater harvesting to be better addressed. This might come about through: 90003 90024 · Development of first-flush bypass devices that are more effective and easier to maintain and operate than those currently available. 90006 · Greater involvement of the public health department in the monitoring of water quality. 90003 90006 · Monitoring the quality of construction at the time of building.Other development needs include: 90003 90006 · Provision of assistance from governmental sources to ensure that the appropriate-sized cisterns are built. 90003 90006 · Promotion of rainwater harvesting as an alternative to both government- and private-sector-supplied water, with emphasis on the savings to be achieved on water bills. 90003 90006 · Provision of assistance to the public in sizing, locating, and selecting materials and constructing cisterns and storage tanks, and development of a standardized plumbing and monitoring code.90003 90006 · Development of new materials to lower the cost of storage. 90003 90006 · Preparation of guidance materials (including sizing requirements) for inclusion of rainwater harvesting in a multi-sourced water resources management environment. 90003 90030 90006 90013 Information Sources 90014 90003 90006 90013 90264 Contacts 90265 90014 90003 90006 90013 90159 Eduardo Torres, 90160 90014 Investigador, Instituto Argentino de Investigaciones de las Zonas Aridas (IADISA), Bajada del Cerro de la Gloria s / n, Parque General San Martín, Casilla de Correo 507, 5500 Mendoza, Argentina.Tel. (54-1) 28-7995. Fax (54-1) 28-7995. E-mail: [email protected]. 90003 90006 90013 90159 Luiza Teixeira de Lima Brito, 90160 90014 Pesquisadora, EMBRAPA / CPATSA, BR-428 km 152, Zona Rural, Caixa Postal 2356, 300-000 Petrolina, Pernambuco, Brasil. Tel. (55-81) 862-1711. Fax (55-81) 862-1744. E-mail: [email protected]. 90003 90006 90013 90159 Jorge Faustino Marco, 90160 90014 Líder, Proyecto RENARAN / Cuencas, Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), Apartado 7170, Turrialba, Costa Rica.Tel. (506) 556-6279 / 556-7830. Fax (506) 556-1576 / 556-1533. E-mail: [email protected]. 90003 90006 90013 90159 Luis Alfredo Ochoa, 90160 90014 Ingeniero, Instituto Nacional de Sismología, Vulcanología, Meteorología e Hidrología (INSIVUMEH), Ministerio de Comunicaciones, Transporte y Obras Públicas, 7a Avenida 14-17, Zona 13, Guatemala. Tel. (502-2) 31-4967 / 31-9163. Fax (502-2) 31-5005. 90003 90006 90013 90159 Ernesto Bondy Reyes, 90160 90014 Director General, Dirección General de Recursos Hídricos (DGRH), Ministerio de Recursos Naturales, 100 metros al sur Campo Birichiche, Tegucigalpa, Honduras.Tel. (504) 32-6250 / 32-1386. Fax (504) 32-1828. 90003 90006 90013 90159 Eugenio Godoy Valdovinos 90160 90014 90159, 90160 Comisión Nacional de Desarrollo Regional Integrado del Chaco Paraguayo, Dirección de Recursos Hídricos, Casilla de Correo 984/273, Filadelfia, Paraguay. Tel. (595) 91-275. Fax (595) 91-493. 90003 90006 90013 90159 Milagros Martínez Esquea 90160 90014 90159, 90160 Ingeniero Agrónomo, Instituto Nacional de Recursos Hidráulicos (INDRH), Programa de Manejo de Agua a Nivel de Finca, Av.Jiménez Moya, Centro de los Héroes, Apartado Postal 1407, Santo Domingo, República Dominicana. Tel. (809) 533-5804 / 532-4863. Fax (809) 532-5889. 90003 90006 90013 90159 José Payero, 90160 90014 Profesor-Investigador, Departamento de Recursos Naturales, Instituto Superior de Agricultura (ISA), Apartado 166, La Herradura, Santiago, República Dominicana. Tel. (809) 247-0082 / 247-2000. Fax (809) 247-2626 / 247-0085 90003 90006 90013 90159 Bwalya John Mwansa, 90160 90014 Project Manager, Barbados Water Resources Management & Water Loss Studies, Barbados Water Authority, «Invermark», Hastings, Christ Church, Barbados.Tel. (809) 430-9373. Fax (809) 430-9374. 90003 90006 90013 90159 Felipe Cisneros 90160 90014 Espinosa, Profesor-Investigador, Instituto de Investigaciones de Ciencias Técnicas (IICT), Facultad de Ingeniería, Universidad de Cuenca, Av. 12 de abril s / n, Cuenca, Ecuador. Tel. (593-7) 831-688 / 819-891. Fax (593-7) 832-183. E-mail: [email protected]. 90003 90006 90013 90159 Bernardine Georges, 90160 90014 Chef, Section Hidrologie, Service National des Ressources en Eaux, Ministère de 1 ‘Agriculture, des Ressources Naturelles et du Développement Rural, Av.Lamartinière 56, Port-au-Prince, Haiti. Tel. (509) 22-4057 / 45-4113. Fax (509) 22-3591. 90003 90006 90013 90159 Johannes Wrann, 90160 90014 Ingeniero Forestal, Instituto Forestal (INFOR), Calle Huérfanos 554, Casilla de Correo 3085, Santiago, Chile. (56-2) 639-6189. Fax (56-2) 638-1286. 90003 90006 90013 90159 Margaret Dyer-Howe, 90160 90014 General Manager, Montserrat Water Authority, Post Office Box 324, Church Road, Plymouth, Montserrat, BWI. Tel. (809) 491-8440. Fax (809) 491-4904.90003 90006 90013 90159 Martha Pinedo-Medina, 90160 90014 Coordinator, Water and Soil Section, Department of Agriculture, Animal Husbandry and Fisheries, Klein Kwartier N. 33, Curaçao, Netherlands Antilles. Tel. (599-9) 37-6170. Fax (599-9) 37-0723. 90003 90006 90013 90159 Martin Satney, 90160 90014 Senior Agricultural Engineer, Ministry of Agriculture, Lands., Fisheries and Forestry, NIS Building, 5th Floor, Castries, Saint Lucia. Tel. (809) 450-2337. Fax (809) 453-6314. 90003 90006 90013 90159 Vincent Sweeney, 90160 90014 Sanitary Engineer, Caribbean Environment and Health Institute (CEHI), Post Office Box 1111, The Home, Castries, Saint Lucia.Tel. (809) 452-1412. Fax (809) 453-2721. E-mail: [email protected]. 90003 90006 90013 90159 Moekiran Amatali, 90160 90014 Director, Hydraulic Research Division, Magnesium Street 41 (Duisburglaan), Post Office Box 2110, Paramaribo, Suriname. Tel. (59-7) 49-0963. Fax (59-7) 46-4901 / 49-0627. 90003 90006 90013 90159 Joseph E. Williams, 90160 90014 Chief Environmental Health Officer, Environmental Health Department, Ministry of Health and Social Security, Duncombe Alley, Grand Turk, Turks and Caicos Islands, BWI.Tel. (809) 946-2152 / 946-1335. Fax (809) 946-2411. 90003 90006 90013 90159 Henry H. Smith, 90160 90014 Director, Water Resources Research Institute, University of the Virgin Islands, # 2 John Brewers Bay, St. Thomas, U.S. Virgin Islands 00802-9990. Tel. (809) 693-1063. Fax (809) 693-1074. E-mail: [email protected]. 90003 90006 90013 90159 Basil Fernandez, 90160 90014 Managing Director, Water Resources Authority, Hope Gardens, Post Office Box 91, Kingston 7, Jamaica. Tel. (809) 927-1878.Fax (809) 977-0179. 90003 90006 90013 90264 Bibliography 90265 90014 90003 90006 Barbados Water Authority. Sub-Committee on Water Resources. 1984. 90159 Report on Supply-Use of Roof and Parking Lot Catchments. 90160 Christ Church. 90003 90006 Bernat, C., R. Courcier, and E.A. Sabourin. 1993. 90159 Cistern 90160 a 90159 de Placas, Técnicas de Construção. 90160 Recife, Massagano. 90003 90006 Economic and Social Commission for Asia and the Pacific (ESCAP). 1989.»Rainwater Harvesting Techniques and Prospects for their Application in Developing Island Countries.» In 90159 Water Resources Development in Asia and the Pacific: Dam Safety Evaluation and Monitoring, Water Tariffs and Rainwater Harvesting. 90160 Bangkok. pp. 101-108. (United Nations Water Resources Series No. 63) 90003 90006 Edwards, D., and K. Keller. 1984. 90159 A Workshop Design for Rainwater Roof Catchment Systems (Training Guide) and Appendix: Rainwater Harvesting for Domestic Water Supplies in Developing Countries.90160 La Paz, UNESCO / ROSTLAC, UNICEF, Instituto de Hidráulica e Hidrología. 90003 90006 EMBRAPA-CPATSA. n.d. 90159 Captación y Conservación de Agua de Lluvia para Consumo Humano. 90160 Petrolina, PE, Brazil. (Circular Técnica No. 12) 90003 90006 Gonguez, P. 1980. «Water Supplies in Off-shore Islands and Coastal Communities.» Paper presented at the United Nations / Commonwealth Science Council (CSC) Seminar on Small Island Water Problems, Barbados. 90003 90006 Gould, J.E. 1990.»Development of Rainwater Catchment Systems: Technology and Implementation Strategies in the 1980’s and Lessons for the 1990’s.» In: 90159 Experiences in the Development of Small-Scale Water Resources in Rural Areas: Proceedings of the International Symposium on Development of Small-Scale Water Resources in Rural Areas, 90160 Bangkok, Carl Duisberg Gesellsehaft, South East Asia Program Office, pp. 95-105. 90003 90006 Hadwen, P. 1987. «Caribbean Islands: A Review of Roof and Purpose Built Catchments.»In 90159 Non-Conventional Water Resources Use in Developing Countries. 90160 New York, United Nations, pp. 455-468. (Natural Resources / Water Series No. 22). 90003 90006 ——, (ed.). 1980. 90159 Proceedings of the United Nations Seminar on Small Island Water Problems. 90160 Bridgetown, UNDP. 90003 90006 ——, and de A. Jong. 1984. 90159 Improvement of Water Supplies in St. Vincent Grenadines. 90160 Kingstown, UNDP Project RLA / 82/023. (Informal Report 17) 90003 90006 Haebler, R.H., and D.H. Waller. 1987. «Water Quality of Rain Water Collection Systems in the Eastern Caribbean.» In 90159 Proceedings of the Third International Conference on Rainwater Cistern Systems. 90160 Khon Kaen, Thailand, Khon Kaen University. 90003 90006 Heggen, RJ. 1984. «Rainwater Catchment Systems: A Review.» In 90159 Proceedings of the Second International Conference on Rainwater Cistern Systems 90160 (H.H. Smithe, ed.). St. Thomas, U.S.V.I., Caribbean Research Institute and Virgin Islands Branch, ASCE, pp.A3.1-A1-13. 90003 90006 Janssens, L. 1978. 90159 Preliminary Assessment of Rainwater Catchment Possibilities at Nassau International Airport. 90160 Nassau, UNDP. (Project BHA / 73/004, Technical Report 3) 90003 90006 Junker, M. 1995. 90159 Abastecimiento de Agua Potable en los Asentamientos Indígenas de Diez Leguas. 90160 Filadelfia, Paraguay. Dirección de Recursos Hídricos de Paraguay e Instituto Federal de Geociencias y Recursos Naturales de Alemania. (Cooperación Hidrogeológica Paraguayo-Alemana, Informe Técnico N ° 1) 90003 90006 Keller, S.1995. 90159 Posibilidades de Desarrollo del Chaco Paraguayo por el Control del Consume de Agua Subterránea y el Aprovechamiento de las Precipitaciones. 90160 Filadelfia, Paraguay / Hannover, Alemania. Dirección de Recursos Hídricos de Paraguay e Instituto Federal de Geociencias y Recursos Naturales de Alemania. (Cooperación Hidrogeológica Paraguayo-Alemana, Informe Técnico N ° 14) 90003 90006 Leung, Ping-Sun, and Yu-Si Fok. 1982. «Determining the Desirable Storage Volume of a Rainwater Cistern System: A Stochastic Assessment.»In 90159 Proceedings of the First International Conference on Rainwater Cistern Systems. 90160 Honolulu, University of Hawaii, Water Resources Center, pp. 233-244. 90003 90006 Lorenzo, Nieves. 1988. 90159 Proyecto de Presupuesto para la Construcción de Cisternas Rurales en los Caseríos Corozalito y el Guanábano del Distrito Zamora Estado Flacón. 90160 Coro, Venezuela, FUDECO-PIDZAR. 90003 90006 MARAVEN. Gerencia de Relaciones Publicas, Gerencia de la Faja Petrolífera del Orinoco.1987. 90159 Tecnologia Alterna Cosechando la Lluvia. 90160 Maracaibo, Venezuela. 90003 90006 Myers, L.E. 1974. «Water Harvesting, 2000. BC to 1974 AD.» In 90159 Proceedings of the Water Harvesting Symposium. 90160 Phoenix, Arizona, U.S. Department of Agriculture. (Report No. ARS-W. 22, 1-7) 90003 90006 ——, 1967. «Recent Advances in Water Harvesting. ‘ 90159 ‘Journal of Soil and Water Conservation, 90160 22 (3), pp. 95-97. 90003 90006 Nova Scotia Department of Health, n.d. 90159 The Use of Rainwater for Domestic Purposes in Nova Scotia. 90160 Halifax, N.S., Canada. 90003 90006 Oliveira, A.M., and J.V. Martinez. 1987. 90159 Tecnologías Simples para Aproveitamentos de Pequeno Porte dos Recursos Hídricos do Semi-Árido Nordestino. 90160 Rio de Janeiro, Associação Brasileira de Geologia de Engenharia. (Artigo Técnico 14) 90003 90006 Oosterbaan, A.W.A. and J.Z. Martinez. 1987. «Cisternas Rurales Tipo CPATSA. Un Manual para su Dimensionamiento, Construcción y Mantenimiento en el Chaco Central, Paraguay.»Filadelfia, Paraguay. PNUD Proyecto PAR / 86/003. (Unpublished) 90003 90006 Penn, Gary. 1986. 90159 The Present State of Water Supply in the British Virgin Islands. 90160 Paper presented by the Chief Engineer of the Water and Sewerage Department at the Fifteenth Caribbean Water Engineers Conference, Tortola, 25-28 November. 90003 90006 Pescatore, Italia, and Nieves Lorenzo. 1987. 90159 Captación y Conservación de Agua de Lluvia para Consume Humano: Cisternas Rurales, Dimensionamiento, Construcción y Manejo.90160 Barquisimeto, Venezuela, FUDECO-PIDZAR. 90003 90006 Pérez Hernández, David. 1994. 90159 Aprovechamiento del Embalse San Francisco y Otras Fuentes Alternas de Agua en Macanao, Estado Nueva Esparto. 90160 Caracas, MARNR. 90003 90006 90159 Proceedings of the First International Conference on Rainwater Cistern Systems. 90160 1982. Honolulu, Hawaii, University of Hawaii, Water Resources Research Center. 90003 90006 90159 Proceedings of the Second International Conference on Rainwater Cistern Systems.90160 (H.H. Smith, ed.). 1984. St. Thomas, U.S.V.I., Caribbean Research Institute and Virgin Islands Branch, ASCE. 90003 90006 90159 Proceedings of the Third International Conference on Rainwater Cistern Systems. 90160 1987. Khon Kaen, Thailand, Khon Kaen University. 90003 90006 90159 Proceedings of the Fourth International Conference on Rainwater Cistern Systems. 90160 1989. Manila, International Development Research Centre, Canadian International Development Agency, and Philipine Water Works Association.90003 90006 Reller, R. 1982. 90159 Rainwater Harvesting for Domestic Water Supplies in Developing Countries. 90160 Washington, D.C., USAID. (Water and Sanitation for Health Project, Working Paper No. 20) 90003 90006 Rinehart, F. 1983. 90159 Water Quality of Cistern Water in St. Thomas, United States Virgin Islands. # 1 90160 John Brewers Bay, St. Thomas, College of the Virgin Islands, Caribbean Research Institute. (Technical Report No. 15) 90003 90006 Ruskin, R., et al. 1988.90159 Maintenance of Cistern Water Quality in the Virgin Islands. 90160 # 2 John Breyers Bay, St. Thomas, University of the Virgin Islands, Water Resources Research Institute. (Technical Report No. 30) 90003 90006 Santos, Walter W. 1992. 90159 Cosechas de Aguas de Lluvias Para Uso Domestico. 90160 Comayagua, Honduras, Centro de Entrenamiento de Desarrollo Agrícola, Dirección de Recursos Hídricos. 90003 90006 Schiller, E.J. and B.G. Latham. n.d. 90159 Sistemas de Captación de Aguas Pluviales.90160 Santiago, Chile, OPS / CEPIS. 90003 90006 Silva, A. de Souza, and E. Rocha Porto. 1982. 90159 Utilização e Conservação dos Recursos Hídricos en Areas Rurais do Trópico Semi-árido do Brasil. 90160 Petrolina, PE, Brazil, EMBRAPA-CPATSA. (Documento No. 14) 90003 90006 ——, et al. 1984. 90159 Cisternas Rurais. Dimensionamento, Construção e Manejo. 90160 Petrolina, PE, Brazil, EMBRAPA-CPATSA-SUDENE. (Circular Técnica No. 12) 90003 90006 ——, et al. 1988 Captação e Conservação de Água de Chuva no Semi-árido Brasileiro: Cisternas Rurais.II. 90159 Agua para Consume Humano. 90160 Petrolina, PE, Brazil, EMBRAPA-CPATSA. (Circular Técnica No. 16) 90003 90006 Smith, Henry H. 1983. 90159 Effects of Various Factors on the Sizing of Rain Water Cistern Systems. # 2 90160 John Brewers Bay, St Thomas, College of the Virgin Islands, Caribbean Research Institute. (Technical Report No. 19) 90003 90006 Thomas, E.N. 1980. «The Artificial and Roof Rainwater Catches of Bermuda.» Paper presented at the UN / CSC Seminar on Small Islands Water Problems.Barbados. 90003 90006 United Nations. Department of Technical Cooperation and Development. 1989. 90159 Roof Catchments, Roof Coverings, Guttering and Downpipes. 90160 New York. (United Nations Water Resources Assessment and Planning in Pacific Islands; UNDP Project RAS / 87/009) 90003 90006 UNEP. 1983. 90159 Rain and Stormwater Harvesting in Rural Areas. 90160 Nairobi, pp. 92-113. (Water Resources Series, 5) 90003 90006 Waller, D.H. 1982. «Rainwater as a Water Supply Source in Bermuda.»In 90159 Proceedings of the First International Conference on Rain Water Cistern Systems. 90160 Honolulu, University of Hawaii, Water Resources Research Center, pp. 184-193. 90003 90002 90003 90002 90003 .90000 10 types of roofs you did not know about 90001 Natural slate Share 90002 90003 90002 When you choose a roofing style, you may first think of visual impact. While good look really matters, so do utility, lifetime and strength. 90003 90002 If you’ve ever wondered what the importance of a good roof is to your home, then do not miss this list! 90003 90008 LEARN ABOUT THE BASIC TYPES OF ROOFS 90009 90002 Choosing a roof shape is more difficult than it seems.There are many different roof types and they all have unique properties. 90003 90012 90013 90014 Gable roof 90015 90002 The term ‘90017 gable 90018’ refers to the triangle spot that is formed when the two pitched areas of the roof meet. 90003 90002 The gable roof is a very popular type of roof: easy to build, sheds water well, facilitates ventilation and can be applied to most house designs. 90003 90002 90003 90024 90013 90014 Hip 90015 90002 Hip roof is slightly more difficult to build and usually has 4 sides.It’s a popular choice but does not provide for ventilation. They do perform better in high wind areas. 90003 90002 90003 90024 90013 90014 Dutch 90015 90002 Dutch roof is basically a hip roof with a small gable at either end. The result is easier access to the lower portion of the roof with the added benefits of natural light and extra space. 90003 90024 90013 90014 Mansard roof 90015 90002 It is a French design and is more difficult to build than the hip or gable roof. It actually features two slopes within one on each side.The bottom part of the roof slope is steeper so that the pitch of the roof barely starts. This allows more room on the inside and in most cases creates an extra space. 90003 90024 90013 90014 Flat roof 90015 90002 Most flat roofs are not really 100% flat, they are low-sloped roofs that appear flat, but have a little bit of a slope to allow for the run-off water. 90003 90024 90013 90014 Shed roof 90015 90002 Shed roof is similar to a flat roof but has more pitch, it is frequently used for additions or with other roof styles.90003 90002 90003 90024 90013 90014 Butterfly roof 90015 90002 This is a very modern design that is aesthetically unique. It provides plenty of light and ventilation but drainage is a problem. 90003 90024 90013 90014 Gambrel roof 90015 90002 It is also called barn roof because it has been used extensively on barns. It provides additional headroom in the attic. 90003 90024 90013 90014 Dormer roof 90015 90002 A dormer is more an addition to an existent roof. It is a window and a roof (gabled, hipped, flat, among others) protruding from the existing slope of the roof.A functional dormer creates usable space out of the roof, adding natural light and headroom. 90003 90002 90003 90024 90013 90014 M Shaped 90015 90002 A M-shaped roof is basically a double gable roof featuring two sloped sides that meet in the middle with corresponding slopes on each side. 90003 90024 90085 90002 We bet you did not know there were so many types of roofs. But what is most important is the material you choose … A natural slate roof is always a safe bet, enhancing the look of your home with incredible technical and aesthetical properties.90003 90002 Find out where to find the best roofing slates. 90003 90002 Do you want to know more about roof styles? Then do not miss these top 10 contemporary houses with pitched roofs! 90003 .