Waterproofing Concrete Slab

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    Concrete slabs especially the top roof which is directly exposed to climatic conditions are very prone to damage and degradation due to natural agents like heat from the sun, rainfall, or snowfall. What happens is that due to the continuous change in the temperature of the atmosphere, the concrete slabs expand and contract numerous times as the years pass by leading to micro-cracks or cracks that are visible to the eyes in the concrete. If these cracks were left untreated it may lead to the corrosion of the steel inside the concrete by the infiltration of the water through the micro-cracks or cracks using capillary action. In the long run, it reduces the durability of the building. Not only does the top roof that is exposed to the atmosphere have water infiltration, but the intermediate slabs also have water infiltration or water leakages due to defective water pipelines, and improper joints in the sunken area of the slabs. This water infiltration not only creates corrosion of the concrete at the same time it also creates dampness in the concrete which leads to poor appearance of the structure.

Cracks in the concrete slabs

Water Proofing

    Waterproofing is the use of suitable methods and adhesives or chemicals to make the concrete resistant to the infiltration or penetration of water. To prevent the damage to the concrete and steel by the penetration of water into the concrete through the capillary action we need to do the waterproofing to increase the durability of the concrete structure.

Methods of Water Proofing

  1. Cementitious waterproofing
  2. Liquid waterproofing member
  3. Bituminous coat waterproofing
  4. Bituminous membrane waterproofing
  5. Polyurethane Liquid membrane waterproofing
Cementitious waterproofing

    This is the most popular type of waterproofing. In this method, a waterproofing agent which is usually a synthetic emulsion polymer is mixed with the cement mix and applied over the slab before the laying of the tiles to prevent water infiltration or seepage. 

    The greatest advantage of this type of method is that it can be easily prepared and applied. However, the disadvantage of this type of method is it can be only applied to floors that are not directly in contact with heat like the sun, which means they are not suitable for slabs that undergo thermal expansion and contraction due to temperature changes by the climatic conditions. 

    So this type of waterproofing is only suitable for Internal toilet floors and internal slabs. This type of waterproofing is not suitable for open terraces.

    Application: They can be used behind the tiles, masonry patching, and concrete surfaces that are not involved in greater thermal expansion

Liquid Water Proofing Membrane

    In this method, a primer coat made of synthetic polymer is applied using a roller, spray, or trowel. This type of liquid waterproofing has greater thermal expansion and contraction properties them cementitious water proofing and hence they are suitable for surfaces that are exposed to sunlight and external climatic conditions.

    Due to the above advantages, they are very suitable for waterproofing the walls and terrace of a building. If the type of the polymer is very good the elongation properties reach even up to 280 percent.

    Application: Very Suitable for Walls.

Bituminous coat waterproofing

    This method is very suitable for the foundation and in places where direct sunlight is not possible because of their nature of becoming fragile and brittle when exposed to Sunlight, especially UV radiation. But nowadays much research has been done and now they we used even on the roof as bituminous roll paper sheets with suitable treatment by adding many additional polymers with it.

    Application: On Footing and where direct sunlight is not possible

Bituminous Membrane Water Proofing

    As I said before, Bituminous membranes are prepared nowadays by the addition of rubber adhesive polymers and mineral granule aggregates. Bitumen is itself a good adhesive but in the raw form when exposed to sun it loses its elastic property and becomes brittle over time. By Adding rubber polymer the property is retained. The sheets or membrane of Bitumen were suitable for low slopes or flat roofs.

    Application: Suitable for Roofs.

Polyurethane Liquid membrane waterproofing

    Polyurethane Waterproofing is on the little expansive side. so if you want to use it thick twice. But it is highly flexible so it is very suitable for high thermal expansion areas. But the only problem with this is during application the surface of the concrete surface needs to be free of moisture. If any moisture is present between the concrete and polyurethane during application the membrane will peel off. So check the surface before application of this membrane.

    Application: Suitable for Roofs.


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