Your construction-related queries answered by Green Evolution, a Chennai-based architectural service firm

I bought a 3BHK Flat in Thiruvottiyur. I paid Rs. 1 lakh for a car park that was 15 ft wide and 18 ft long. The builder has sent me a notice stating he will allot me an 8 by 7 ft section of this to me and sell the rest to another resident. What is the standard car park stall size as per CMDA norms?

M. Mineesh, Thiruvottiyur

As per CMDA regulations, the minimum size of a car parking space is 2.5 m (8’2”) wide and 5 m (16’4”) long.

The terrace of my house is 22 years old. A traditional weathering course was employed. Then, seven years ago, two coats of paint were applied but the wear and tear is obvious now. How can I effectively waterproof and apply thermal insulation simultaneously to my terrace? What would this cost per sq. ft?

Felix Moses, Arumbakkam

These days, there is a wide range of options available for water- and weather-proofing. For a simple solution, consider an elastomeric coating with interlocked fibre mesh (e.g. Greenseal 108 or Polyplus HR) on top of the existing weathering course that would act as water-proofing as well as heat-reflective coating. However, the life of this depends on how much access you allow to your terrace (the lesser the better) and how dust-free you maintain the roof surface.

For a more effective and longer lasting solution, try membrane water-proofing on a base primer followed by a 30mm layer of rigid insulation (XPS, EPS, etc.), finished with a heat-reflective coating or tile (longest lasting) as the topmost layer for weather-proofing. This treatment will make the existing weather-proofing layer redundant and will also increase the load on the roof. So, if you opt for the second kind of solution, we would recommend that the existing weather-proofing layer be removed.

Costing could range anywhere from Rs. 60 per sq. ft for the elastomeric coating to about Rs. 200 per sq. ft for membrane waterproofing, rigid insulation and heat reflective tile finish. A heat-reflective coating instead of the tiles will bring down the cost by about Rs. 30 per sq. ft.

Send in your queries to hinduhabitat@gmail.com. All queries must have your name and address.

More In: Q & A | Habitat | Features | Chennai