Please permit me to share with worthy readers my unpleasant experience with commercial waterproofing and the remedy adopted for long lasting waterproofing.

An Islamabad based company charged Rs185,000 for roof waterproofing of two houses and repair of one overhead water tank with some black bituminous emulsion with a 3-year warranty. Waterproofing failed within six months and the drinking water was contaminated with fine bitumen particles. The black rooftop made houses ovens during the summer. The company offered a better waterproofing system at about the same additional cost which I declined.

An old experienced architect recommended the old well tried British colonial system of two layers of bitumen covered with mud plaster and large bricks (Chaukas) with cement grouting and fine coating of bricks. Addition of suitable grade plastic sheet on bitumen layers is now an added waterproofing. This procedure requires scrapping of existing fancy waterproofing. Interestingly, it cost me Rs120 per square foot as compared to Rs30 to Rs45 charged by most waterproofing companies with three or four-year warranty which may or may not work. Countless companies are operating with dubious performance.

I know some houses of British colonial period with above stated waterproofing, also providing some heat proofing, procedure without leakage problem.

M. AKRAM NIAZI,

Rawalpindi, May 31.