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Opt for shell concrete roofing
Placing the roof structure on the building
What you need to know:
- With most building material being sold at a high price, using cheap alternatives such as shell concrete roofing, is a solution you can consider.
With the high cost of building residential and commercial houses, innovative minds are always coming up with ways to make construction projects more bearable. A cheaper and emerging way to build a roof is to use thin shell concrete. Thin shell concrete roofs are about a centimeter thick and rely on much less timber than other types of roofs would have required. Ad even brighter prospect is that the roof can be completed in about 10 days.
How its built
Steven Jjuuko Kwagala, a graduate architect and construction professional who has used the technology on a number of building projects, says with this kind of roof, one does not need a ceiling or iron sheets.
“A structural frame made of material, such as, timber or steel is built together in the shape of a roof, hyperbola, or any other shape the contractor desires. The frame is then reinforced at the corners to ensure it is stable. Then, inorganic cloth, (not cotton) such as khaki or fiberglass, is stretched over the timber frame, and chicken wire mesh is stretched over the cloth. The khaki and wire mesh are bound – at the edges – to the timber using thin wire or unbreakable thread, such as nylon.”
Placing it
The framework shells can be built onto the building or can be built away from the site, moved, and assembled before the concrete is poured on it. A mixture of concrete – sand, cement, and water – is added to latex in a drum or whatever container is on hand.
The mixture is then poured out over the wire mesh that is nailed to the framework. The hard quality of the khaki cloth or fiberglass stops the wet mix from seeping through.
Using a synthetic paint brush (with plastic bristles) the mixture is spread out over the framework until the wire mesh disappears from sight.
“For about three days, everyday a layer of concrete and latex mixture is added to the initial layer,” Kwagala advises, continuing, “This should be done until the roof has a thickness of one centimeter of concrete.”
Weather proof paint can be applied on the structure before a layer of transparent sealant is spread over it. After the roof has dried, a crane is used to carry it to the building.
Disadvantages
If the roof is made by an inexperienced person and a small amount of concrete is smeared onto the framework, there is a possibility that the roof will become porous, allowing rain water to seep through and leak into the building. Also, concrete can prevent air from escaping the building. However, this can be addressed by having enough ventilation outlets.
Kwagala also contends that concrete roofs need specialised labour because they are not common. Finding such labour is not easy. Besides, the shapes of the roofs may not be to one’s taste.
PROS
This type of roof keeps the heat out and when it rains, you cannot hear the sound of the rain drops. It is strong and fire-resistant. The nature of the design also gives the house a lot of headroom.
As an alternative way of building, thin shell concrete can save you up to 25 per cent on your roofing costs as compared to if you use iron sheets.
