In your dad’s house
Amit Gupta, chairman and managing director, Cico Technologies offers a simple reason on why your dad never told you how to deal with leaking roofs. He probably never faced the situation. Before the 70s, says Gupta, brick house were built with very good quality materials. “The most effective waterproofing solution is proper water ratio in the mortar that goes into: binding the bricks, on the terrace, and on the external walls. The ratio is 30 per cent of cement. Any more or less and water will literally plague the building for the rest of its life,” he adds and he should know what he is saying because he is member of the National Council of the Construction Federation of India.
Excess water will leave voids in the cement when it evaporates. The problem arises because masons today tend to add up to 50 per cent water because it makes the mortar easy to work with.
To ease the situation these days super plasticisers are available, 1 per cent of which when added to mortar will make it easy flowing and easier to work with while maintaining high density. Gupta says that the best of waterproofing solutions, which include plasticisers and many other solutions, would add only 3 per cent to the cost of constructing a new house.

Despite best efforts
There are no quick fix solutions to water seepage because water—like life—always finds a way. To be fair however, seepage will occur after some time in most houses says, Pankaj Pokharna, head (technical services for water proofing division), Pidilite Industries. Construction quality and masonry skills notwithstanding, environmental factors such as thermal expansion due to difference between summer and winter temperatures (47ºC to 2ºC respectively) in a place like Delhi, and increase of pollutants in the air can deteriorate otherwise good constructions.
By incorporating waterproofing treatment in your construction plans, you can delay these problems by up to 30 years, says Pokharna.

In your house
You may not have got yourself the strong, durable house (like your dad’s) in a metro city. So, here is some information you can use and pass on to your kids.
First, unlike in the West, waterproofing is not a DIY (do it yourself) thing in India. Our houses are different and we live in them differently. We use our terraces more often and our house walls are made of bricks, not pre-fabricated planks. So, you can’t lay the floor of your terrace on your own and neither would your walls leak only from a joint in the plank.
If water is seeping into your house, call a good mason. Many companies offer certificates to masons for successfully completing the training in the use of new techniques and materials. These masons can be contacted at your local hardware distributor.
It is important to state that dampness does not always come via the rains. Leaking overhead tanks and rusty water pipes need to be dealt with as much as a broken roof or a cracked wall.
Also, not all water seepage problems may need a waterproofing expert. Gupta says that if the construction quality of a house is good, a majority of the leaking roofs can be fixed easily by giving the correct slope to the terrace floor. But in the most serious situations the only long-term solution is relaying of the roof. If you are looking to avoid that inconvenience , there are other solutions.
On a roof you could use acrylic, polymer, or latex compounds mixed with cement. Unlike the traditional solutions, these are now available in liquid forms. These are not mixed in the cement but in the water that is used for mixing the cement. This avoids the compound lumping up and ensures better dispersion on the floor.
More expensive but more effective solutions, according to Pokharna, are impervious membranes. A modified bituminous membrane has to be applied with a hot torch, and EPDM (ethylene-propylene-diene-monomer) based rubber sheets can be cold applied with special adhesives. Both these need to be covered up with another layer of tiles or flooring.
For the exterior walls, you can use water repellents like acrylic- or silicon-based paints and sprays, or coatings such as those of pure PU or better still an epoxy-PU combination. Gupta however, has reservations regarding silicon-based water repellents. He says that rather than spraying, silicon compounds are most effective only if the bricks are saturated in them. But very few constructions would be done in such a laborious manner.
The epoxy-PU combination coats would give your walls the benefits of an elastic coating that could protect against thermal expansion and keep at bay small cracks from appearing. If repellent and coatings are used in combination, says Pokharna, the solution can last longer.
While exterior paints are effective, says Pokharna, they offer a thickness of 60 microns only while coatings are of 125 microns. The option of relaying the damages exterior wall plaster, using cement-based acrylic compounds also exists.
Basements can also be problem areas. If despite good construction, seepage does creep in, the solution lies in injecting crystalline or polymer grouts into joints of the construction or wherever seepage is taking place. Gupta says that the crystalline grout is good for areas where basement is not near water. The crystals react with water and and form salts that close the capillaries in the cement, preventing any cracks from widening. The polymer reacts with water to form a gel, which could hold against running water as well. In fact, that is how most coatings work, but grouts epitomise that process.
Finally, remember that waterproofing is done best during the dry season. So, if there is no emergency, don’t run to get a mason right away. Wait for the rains to get over before you call in the experts.