How To Make Concrete Water Tight To Make The Construction Durable

The consistency of concrete is very much required for some specific types of projects which range from water storage tanks, reservoirs, basement walls, roofs, swimming pools, sewage units, etc. Usually, if concrete is compacted and does not contain any crack, it is defined as waterproof. In order to make concrete compacted, the following guidelines should be followed :-

1. Utilize a high class Portland cement having supreme quality.
2. Be extremely careful for proper grading and proportioning of the sand, aggregate and cement.
3. Apply pur and non-porous aggregate.
4. Blend the concrete mix carefully maintaining the exact conformity with the use of sufficient amount of water.
5. Take proper care for placing, tamping and curing.
6. Utilize appropriate water-proofing compound.

The cement concrete becomes water-tight to some extent if hydrophobic cement is added to it. Presently, all the flat roofs are usually built with R.C.C. It is required to take some preparation for making such roof water-tight.

How to make concrete water-tight
Given below some recognized methods for waterproofing of R.C.C. flat roofs:
1. Finishing
2. Bedding concrete and flooring
3. Mastic asphalt and jute cloth
4. Use of water-proofing compounds

In ordinary buildings where construction cost is very low, the completion of roof surface is executed while placing cement concrete. The completion work of flat roof is performed in cement mortar following the ratio of 1:4. It means one part of cement to four parts of sand by volume.

Bedding concrete and flooring
Under this system, the surface of R.C.C. slab is retained rough and on this surface, a concrete layer is placed. The concrete contains brickbats lime concrete (1:2:4) or brickbats cement concrete (1:8:14). The thickness of the concrete layer remains about 100mm. The surface of the bedding concrete is created with proper flooring like tiles, terrazzo, Indian patent stone, etc. A convex joint is placed at the meeting point of parapet wall and roof.

Mastic asphalt and jute cloth
Under this system, a layer of hot mastic asphalt is placed on the roof surface. The jute cloth is extended upon this layer. After that another layer of mastic asphalt is placed to get the jute cloth inserted among the two layers of mastic asphalt. The sand is then circularized to the whole surface of roof. To absorb it in a superior manner, the lead sheets are incorporated at the meeting point of parapet wall and roof.

Application of waterproofing compounds
Some of the watertight compounds like Pudlo, Impermo, etc. can be found in the market and if these type of compounds are included to the cement throughout construction, it stops seepage, leakage and damp due to the capillary absorption of the moisture in cement, mortar and concrete. The required quantity of water-proofing compound is also very minor, as for example 2% and so a bag of cement will need only about 10N of such compound.

The water-proof compounds can be obtained in the powder form and these are blended comprehensively with cement manually prior to the cement is blended with the aggregate.


How to make concrete water-tight

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