BuildwiseSolar-ready roofs are becoming standard on new builds
Designing roofs to take panels later costs little now and saves a lot afterwards. Here is what to include in the design.
By Buildwise Editorial2 min read
Adding panels to a roof that was never designed for them is expensive. Retrofitting structural strengthening, running new cable routes through finished ceilings and working around vents and flues placed without a thought for future panels can turn a straightforward solar installation into a disruptive, costly job. Designing for solar from the start costs very little in comparison.
What solar-ready actually means
A roof pitch and orientation that suit panels is the obvious starting point, but the more valuable decisions are the ones that are invisible once the building is finished: structural capacity for the extra load, clear routes for cables between roof and consumer unit, and a layout that keeps the best-performing areas of roof free of obstructions.
Structural capacity is worth specifying explicitly rather than assuming it comes for free. Solar panels are not heavy compared with roof tiles, but the point loads at fixing brackets and the wind uplift on an unbroken array both need to be checked against the actual structure, not against a generic assumption made at the concept stage.
Practical tips
Keep vents, chimneys, roof lights and satellite mounts away from the best-performing roof areas, since every one of them creates a shadow or a gap that panels have to work around. Reserve wall space near the roof for an inverter, ideally somewhere ventilated and out of direct sun, and route a conduit from roof to consumer unit while the walls are still open, even if the panels themselves are not part of the initial build.
Agree access for maintenance at the design stage too. A roof that can only be reached with a scaffold adds a cost to every future panel clean, inspection or repair that a walkway or a well-placed access hatch would have avoided.
Sizing for tomorrow, not just today
Panel technology and household electricity demand both keep changing, and a roof designed for exactly today’s typical array can end up undersized within a few years, particularly as heat pumps and electric vehicle charging add to household electricity use. Specifying a consumer unit with spare capacity and a cable route sized generously rather than to the minimum keeps the roof useful for longer without a second round of building work.
The extra design time is small compared with the savings later
None of this adds significant cost to a new build when it is planned in from the start. The same work done after occupation, through finished ceilings and around an inhabited roof, routinely costs several times more and causes disruption a design decision could have avoided entirely.
