Life in colour
Roof waterproofing before the monsoon, step by step
4 min read
Six simple steps to waterproof a flat roof before the rains, so the ceiling stays dry this year.
Step 1: Inspect and clean
Go up to the roof on a dry day. Look for cracks, places where water stood last year, loose plaster, and the joints where the parapet wall meets the floor. Then clean the whole roof. Sweep away dust and leaves, scrub off moss and black patches with a wire brush, and wash it down. Let it dry fully.
Step 2: Fill the cracks
Open every crack a little with a scraper so the filler can grip. Brush out the dust. Fill the cracks with a crack filler or a cement-based waterproof putty, pressing it in well. Pay extra attention to the corners, around pipes, and the base of the water tank. Let the filler cure as the pack says before you move on.
Step 3: Primer or sealer
A waterproofing coat holds on better when the roof has a primer or sealer under it. Mix the primer as the tin says and roll or brush it over the full roof, including the parapet walls up to about knee height. This coat soaks into the surface and gives the main coating something to stick to. Let it dry.
Step 4: First coat
Now apply the first coat of waterproofing coating. Start from the far corner and work towards the stairs so you do not walk over fresh paint. Use a roller for the flat area and a brush for the corners, pipe bases and the parapet joint. Keep the coat even. Do not try to make it thick in one go.
Step 5: Second coat
Wait for the first coat to dry as the tin says, usually until it no longer feels tacky. Then apply the second coat in the opposite direction, so if the first went north to south, this one goes east to west. This crosses over any thin spots. Two proper coats are what make the roof hold out the rain.
Step 6: Keep the invoice and register the warranty
Keep the shop invoice and the tin label in a safe place. Many waterproofing coatings come with a warranty, and it usually has to be registered soon after the work, through the company's helpline or website. Ask us at the counter whether the product you bought has one, and we will help you register it before you leave the shop.
Ask us at the shop
Not sure how bad your roof is, or how much coating to buy? Take a few photos of the roof, especially the cracks and the corners, and bring them to our shop in Amravati or send them on WhatsApp. We will tell you which Birla Opus waterproofing coating fits your roof and roughly how much you need. The advice is free.
