Fix the terrace first. Then bolt 25 years of panels onto it.

Solar is a 25-year tenant on your roof.

Most solar quotes talk about panels, inverters and subsidy. Few talk about the roof underneath. That is a mistake, because your panels will sit on it for decades, and getting to a leaking slab later means working around a fixed array. Before you sign, look at what you are actually bolting onto.

Start with the roof type.

Most Bengaluru homes have a flat RCC slab, and that is the simplest case for a rooftop system. A sloped roof with sheets or tiles needs a different mounting approach, and tiles in particular can crack under foot traffic during installation. If your roof is old asbestos or weak sheeting, ask whether it is safe to walk on and carry a load at all. Your installer should look at the roof in person before quoting, not price it from a satellite image alone.

Waterproofing comes before panels, not after.

Mounting structures are fixed to the slab, usually on concrete pedestals or anchor points. Every fixing point is a place water can find a way in if the treatment around it is poor. Bengaluru's monsoon will find any weak spot, and a leak under a panel array is slow and annoying to fix.

If your terrace waterproofing is old, cracked or already seeping, redo it first and then install. Ask the installer how they seal and finish around each pedestal or anchor, and who is responsible if a leak appears at a fixing point. Get that answer in writing, because a leak dispute between a waterproofing contractor and a solar installer usually ends with the homeowner in the middle.

Look at the mounting structure itself.

The structure is the part people skip over, yet it holds the whole system up. Ask for the following before you agree to a quote.

Material and finish. Structures are typically galvanised steel or aluminium. Ask which one, and what coating or thickness is being supplied. Bengaluru is not coastal, but monsoon moisture over many years still punishes thin or poorly finished steel.

Height above the slab. A raised structure leaves room to clean under the array and lets water drain off the terrace. A very low one makes cleaning and waterproofing inspection harder. It also affects the space you keep for other rooftop uses.

Wind and anchoring. Panels act like sails in a strong wind. Ask how the structure is anchored and whether the design accounts for wind load. A vague "it is standard" is not an answer. A competent installer can explain the fixing method in a sentence or two.

Plan the terrace you still need.

Your terrace probably does other jobs too: water tank, clothes drying, a stairwell, maybe a small garden. Sketch where the array goes and where people walk. Leave a clear path to the panels for cleaning and inspection, and keep the array clear of tanks and parapets that cast shade, which we covered in our guide to rooftop shading. Also ask where the cable route and inverter will go, so nothing gets drilled through fresh waterproofing later.

Questions for your installer.

Take these to the site visit. Does the installer inspect the roof in person? What structure material and coating will they use? How are fixing points sealed, and who covers a leak? Is the design considered for wind load? Can you see the layout drawing before installation day? If answers come back vague, treat that as information about how the job will go.

The structure and workmanship terms should also be part of the agreement, alongside the warranty details covered in our inverter warranty guide. Panel and inverter warranties do not cover a leaking terrace.

The short version.

Your panels are only as reliable as the roof and structure under them. Check the roof type, fix old waterproofing before installation, ask for the structure material, height and anchoring method, and agree in writing who is responsible if a fixing point leaks. It costs you one careful site visit and saves you a hard conversation later.