Putting Solar Panels on Your Terrace? Waterproof It First

Rooftop solar is a good fit for a lot of Bangalore homes, and the terrace is where it goes. The catch is that most installers focus on panels, structure and wiring. Few ask the question that matters to your ceiling: is the slab under this array dry and sealed?

If you are planning solar this season, here is the order we recommend, and why it saves you a headache later. We are a waterproofing contractor, not a solar installer, so this is about the terrace only.

Why the order matters

Once the mounting structure is bolted down and panels are on it, the slab underneath is hard to reach. Cleaning the surface, repairing cracks, laying a coating and letting it cure all need open, clear floor. If a leak shows up in your top-floor ceiling a year later, the choice may be to work around the frames or to have the array lifted. Both cost time, and lifting panels usually means calling the installer back.

Solar also changes how the terrace behaves. Frames and rails can slow water flow across the slab, shade patches stay damp longer, and leaves and dust collect around the legs. A terrace that was only marginal before can start leaking under that array.

Before the installer arrives

1. Look at the ceiling below. Stains, peeling paint or damp patches on the top-floor ceiling mean the terrace already has a problem. Fix it first.
2. Inspect the terrace itself. Look for hairline cracks, hollow-sounding patches, lifted or broken screed, and gaps where the floor meets the parapet. Our terrace waterproofing guide covers what repair involves.
3. Check the drains. Outlets and downpipes should be clear and the slope should lead water to them. See terrace drain blockages.
4. Waterproof the full terrace, not just the array footprint. Water finds the weak spot, so a patch under the panels leaves the rest exposed.
5. Let it cure fully before any structure goes on, and agree the install date with that in mind.

The bolt points are the weak spots

Many mounting structures are fixed to the slab with anchor bolts or concrete footings. Every one of those is a point where the waterproofing layer is interrupted. Ask your solar installer how the structure is fixed, then plan the sealing with them:

• Raised footings or pedestals are usually better than drilling into a finished waterproof surface, because the waterproofing can be carried up and around them.
• If bolts must go through the coating, each hole needs proper sealing around it. Silicone alone on a hole drilled into a wet slab is not a plan.
• Do not let anyone drill after waterproofing without telling the waterproofing team. A repair afterwards is cheap; an unknown puncture is not.

Already installed and leaking?

If the panels are already up and a leak has appeared, do not assume the panels are the cause. Check the usual suspects first: cracks, failed parapet joints, blocked outlets. The open areas between frames can often be treated, and a site visit will tell us what is reachable. If the repair needs the array to be moved, we will tell you that straight rather than promise something that will not last.

Where LoklFix fits

We inspect the terrace, repair cracks and joints, waterproof the whole slab, and seal around parapets and outlets. We can also coordinate timing with your solar installer so the coating cures before the structure goes up. See our roof waterproofing services.

Frequently asked questions