Case study: installing solar around a rooftop water tank

Very few Kerala roofs are empty rectangles. They have water tanks, staircase rooms, dish antennas, vent pipes and the occasional jackfruit tree leaning over one corner. This installation for our client Harikumar is a good example of designing around reality instead of pretending it away.

The problem

The best south-facing stretch of the roof was occupied by the house's water tank, and the tank could not move. Placing panels straight onto the remaining area would have pushed part of the array into the tank's afternoon shadow, quietly costing units every single day for 25 years.

The solution

We mapped the tank's shadow across the day during the site survey, then split the array on an elevated structure that lifts the panels above the shadow line and leaves the tank fully accessible for cleaning and maintenance. The elevated structure also improves airflow under the panels, which helps output on hot days.

The result is a layout that produces within a few percent of an unobstructed roof. The full installation film is embedded above.

What this means for your roof

An obstacle on the roof almost never rules out solar. What it rules out is a design done from a phone photo. If a company quotes you a system without standing on your roof and watching where the shadows fall, the obstacle is not the tank; it is the survey.