Waterproofing is a crucial step in constructing buildings, especially when it comes to flat roofs. There are several straightforward methods employed to make sure water doesn’t seep through. In this discussion, we’ll explore three of the most commonly used techniques for waterproofing flat roofs.
In cases of ordinary and budget-conscious construction, it’s recommended to finish the rooftop surface with a cement mortar mix, ideally in a 1:4 proportion (one part cement to four parts sand). To counteract the shrinkage and expansive effects of cement concrete or mortar, lime cream can be added to the finishing layer.
Another effective method involves applying a mastic layer of asphalt onto the roof surface before laying down mud or lime concrete. At times, an additional layer of asphalt may also be laid on a finely finished roof surface, which is subsequently sanded and thoroughly polished.
This method starts with ensuring the top surface of the Reinforced Concrete Cement (R.C.C) slab is intentionally kept rough during the casting process. Following this, a 100 mm thick layer of brick-bat lime concrete in a 1:2:4 proportion or brick-bat cement concrete in a 1:6:12 proportion is laid over the R.C.C slab. This layer of concrete is referred to as bedding concrete.
Subsequently, the surface of the bedding concrete undergoes proper finishing, which may involve the use of tiles or other suitable finishing materials. This meticulous finishing not only ensures a smooth surface but also adds an extra layer of protection against water penetration.
To put these methods into perspective, let’s consider a scenario where a flat roof is being constructed for a small commercial building. The construction team decides to use the ‘Asphalt Layer’ method for waterproofing. They apply a mastic layer of asphalt to the roof surface before placing the lime concrete. This provides an added layer of defense against potential water damage, ensuring a dry and secure interior.
In summary, these three methods provide practical and cost-effective ways to waterproof flat roofs. By understanding and employing these techniques, builders and contractors can safeguard their structures from water-related issues, prolonging the life and integrity of the building. Waterproofing is not just a recommended step, but an essential one in ensuring the longevity of any construction project.