Edited by Namakhonje
A roof is the top cover of a building supported by the walls of the building. It entails all materials and members that are required to erect and firmly hold the roof covering material in place. From wall plates, to tie beams, ties and struts, purlins, the ridge, rafters and the roof covering. A roof is vital for any given building. Its main function is to shelter the inhabitants from weather elements like rain, strong wind, intense sunshine or snow in some areas. Various roof designs are available depending on the type of building, its function, climatic conditions in that area, or even the owner’s preference. The two main designs used in Uganda are inclined roofs and flat roofs. Inclined roofs include the hipped and the gable roof designs. The roof is assembled through a systematic sequence of arrangements of the various members. As a construction expert or prospective home owner, one ought to be conversant with various roof designs and materials. This article examines one of the most vital parts of the roof, the roof covering as well as the various materials used as roof coverings, their pros and cons and average prices. This can help in decision making when it comes to considering options. Because the roof covering is the part of the roof exposed to weather elements, careful consideration has to be made in picking a covering material that suits the particular weather conditions of that place. One should also consider costs. Because different roof covering materials have different prices, the construction budget also has to be put into consideration. Since various roof covering materials come in different colors and textures, aesthetics also has to be considered, how appealing a roofing material looks and whether it is compatible with the rest of the building. Roofs can be divided into two broad categories, inclined roofs and flat roofs.
For inclined roofs, the roof covering can either be in form of sheets, thatches or tiles and shingles.
In this case, the roofing material comes in form of large sheets with varying length, breadth and thickness. The most common material used for making roofing sheets are metal and plastic. Other materials include polystyrene and bitumen.
Metal sheets are the most commonly used. Metal roof sheets are usually made of steel, iron, zinc or aluminum. They are incredibly durable and had to break. Since rust is the biggest cause of wear of metal sheets, durability is measured in terms of metal sheets ability to resist rusting. Manufacturers use cutting age technology to improve the sheet’s ability to resist rusting. From painting and oiling, to advanced technologies like galvanizing where sheets are coated with zinc by electrolysis. Roofings; a manufacturing compan, was the first to produce AluZinc(AZED) iron sheets in Uganda. The technology involves coating pre-painted iron sheets with an aluminum-zinc alloy. That is the equivalent of building a twelve-inch-thick concrete wall just to stop an air balloon from passing through. Metal roof sheets come in three different categories depending on their design. There are the corrugated metal sheets, the box profile and tile profile metal sheets. The corrugated metal sheets basically consist a pattern of smooth uniform folds on the surface of the sheets.
The box profile sheets consist of a series of square shaped folds arranged along the surface of the metal sheet.
The tile profile metal sheet consists a pattern of smooth curves that take the appearance of tiles.
The variations in design are mainly for visual appeal, and by far the tile profile sheets give the best appearance but don’t take my word for it. At Roofings group, the box profile and corrugated metal sheets both go for about shs. 40,000- shs. 52,000. The tile profile metal sheet goes for shs. 62,200-shs. 66,600.
Modifications in design include bullnose iron sheets which are normal metal sheets but curved into a convex or concave shape. They provide protection from direct sunshine hence they provide good shade and insulation. They also improve the appearance of the building. They are commonly used in shopping malls, hospitals, warehouses and factories.
Plastic sheets are relatively cheaper than metal sheets, however, they are temporary and only used for outbuildings, shades for balconies and garages. These make use of polymers like poly-vinyl-chloride and poly-carbonate. These polymers can be fabricated into various shapes by casting or molding. They are can be molded into shapes similar to that of corrugated metal sheets, box profile sheets or tile profile sheets. They are generally lighter and easier to assemble but are not as durable and easily ware out with time. They are more vulnerable to extreme sunshine, since plastic is sensitive to high temperatures. Some are even made transparent and used to let light into the house like night lights. They are also used extensively as shades for balconies.
At Roofings group, these go for around shs. 73,700-shs. 114,100 for a three-meter-long sheet.
Pros of metal and plastic sheets
The advantage of opting for sheet roofing materials is that they are lighter, relatively cheaper and easy to install compared to tiles or shingles. They require less timber for support, less expertise to assemble and generally less intricacies involved. They are also easier to maintain.
Cons of metal and plastic sheets
When it comes to appearance, much as sheets may look good when they are new, they wear out very first and become less appealing. Iron sheets may also make the interior quite uncomfortable especially in very hot areas.
Tiles and shingles
These consist smaller units of material arranged in an overlapping pattern to cover the roof. Though tiles and shingles may appear similar at first glance, they have a few differences.
Tiles are generally heavier than shingles. They are made out of materials like clay which is the most common, concrete, plastic or metal. These tiles are individually expensive hence makes the general cost of tiled roofs expensive. The heavy weight of the material also poses relative complexity in installation of these tiles as they may require expertise and reinforcement to the roof which further increases the installation costs of tiled roofs. However, in spite of all that, they are far more durable than shingles. They are also more flexible in design. Milton Erongu from Uganda clays limited says they manufacture a variety of tiles including the Mangalore tiles, Merseilles tiles, Portuguese tiles, flat-top and roman tiles. They cost 3000/=, 3200/=, 3600/=, and 2000/= respectively.
A side from clay tiles, plastic tiles are also another option. They are relatively lighter and easier to install compared to clay tiles. One also doesn’t have to worry about a leaking roof since plastic is water tight. Maintenance costs are also reduced compared to clay tiles which develop algae over time besides the fact that they can be recycled. Plastic tiles are produced by companies like Resintile East Africa. Since the raw material used is plastic, it makes use of a material which is considered the most hazardous pollutant, hence it is environmental friendly.
Whereas tiles come in a variety of shapes and designs, shingles are mostly flat and rectangular. The most common material for making shingles is asphalt, but other materials also include wood, slate, plastic, among others. They are relatively cheaper to purchase compared to tiles. Since they are lighter than tiles, they are relatively simpler to install which is done by nailing or sealing it to the roof frame. This generally brings down the overall costs of construction of such a type of roof. However, shingles are not durable hence easily wear out as compared to ttiles.
Pros of Tiles and Shingles
When it comes to looks and design, tiles and shingles set you a class apart as a person with exquisite taste. They look elegant and classy compared to common iron sheets. Besides that, tiles provide comfort and pleasure to the inhabitants. Its ability to maintain the internal temperature comes in handy especially in hot climates like Uganda.
Cons of Tiles and Shingles
For tiles specifically, perhaps the biggest draw-back is that they are really expensive. A tile on average costs between shs. 2,000-shs. 3,600 at Uganda clays limited. For an average sized house that would require at least a few thousand tiles, the total cost is enormous. Because they are relatively heavier compared to sheets, tiles and shingles not only require more timber for a more stable frame, they involve more design complexities which in turn translate into higher costs of construction. If not well fixed, tiles and shingles may cause linkages. Their maintenance costs are also significantly higher than sheets.
One can’t talk about roofs and forget to mention the grass thatched roofs, the predominantly used roofing type in Uganda. These roofs are constructed using dry vegetation like grass, straw, water reed, palm branches or papyrus. A few grass types used in Uganda include ‘Obukuli’ from Northern Uganda and ‘Kalenziwe’. To thatch an ordinary house, one may need 200-400 bunches of grass, each going for between shs. 3,000- shs. 10,000 depending on the season. Of late, grass thatch houses have become increasingly rare with the dominance to either roof sheets or tiles. Currently they are mostly popular in the rural areas, however, a few modern buildings still adopt this roofing method especially for constructing shades. They are also increasingly popular in recreational and hang out spots like bars, restaurants and clubs.
Pros of Grass Thatches
Grass thatches are well known for maintaining cool temperatures inside the building they shelter even under hot conditions. This means they create a refreshing ambiance for relaxation, socializing and recreation. They are also very easy to erect since they basically require inexpensive vegetative material and minimum level of expertise. Grass thatch also adds a stylish, vintage and unique look an average modern home.
Cons of Grass Thatches
The biggest drawback of grass thatching is that dry grass is very flammable and this possess high risks of spreading fires. This makes grass thatching unappealing from a safety point of view. It’s no wonder that building regulations in most urban areas restrict the use of this type of roofing. They are also susceptible to leakages if not well assembled.
What we have looked at were all inclined roofs. However, there are also a less common type of roofs, flat roofs. They are mainly used in arid or semi-arid regions with low rainfall totals. They may appear flat but they are usually very slightly inclined at an angle less than ten degrees. That is to allow adequate drainage of water which is usually channeled to a gutter. Common materials used for constructing flat roofs include but are not limited to; bitumen, concrete, synthetic rubber among others.
Pros of Flat Roofs
Flat roofs are generally cheaper and easier to construct than inclined roofs. On top of that they provide an extra space for other activities like you can set a roof top garden or it can simply be a relaxation area.
Cons of Flat Roofs
Perhaps the biggest drawback of flat roofs is drainage. Since they are not inclined, they don’t drain water easily and so much attention has to be given to its drainage. Flat roofs are also not so appealing when it comes to looks, they look very basic and boring.
These are the various options available for you to consider when seeking to put a roof on your house. Each one of those choices have their own pros and cons so it’s important that you carefully weigh those options and align your choice with your objectives, function of building, construction budget and discerning tastes if any. Some areas also have building regulations that dictate one’s choice of roofing hence it’s imperative to make prior consultations before rushing in to construct a roof.
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