AN Islamabad-based company charged me Rs185,000 for roof waterproofing of two houses and repair of one overhead watertank with some black bituminous emulsion with a warranty for three years. Waterproofing failed within six months and drinking water was contaminated with fine bitumen particles.

The black rooftop turned houses into oven during the summer. The company offered a better waterproofing system at about the same additional cost which I declined.

An experienced architect recommended the old well-tried British colonial system of two layers of bitumen covered with mudplaster and large bricks (chaukas) with cement grouting and fine coating of bricks. A suitable-grade plastic sheet on bitumen layers adds to waterproofing. This procedure requires scrapping existing fancy waterproofing.

Interesting, it cost me Rs120 per square foot as compared to Rs30 to Rs45 charged by most waterproofing companies with three -to- four-year warranty, which may or may not work. Countless companies are operating with dubious performance.

I know some colonial period houses with the above-stated waterproofing, also providing some heat proofing, I would request relevant experts to comment.

M. Akram Niazi

Rawalpindi Cantt

Published in Dawn, June 6th, 2017