Installing solar panels on tiled roofs

Fitting solar panels to a pitched tiled roof worries people more than almost any other part of a domestic installation, and the questions are usually about load rather than electrics.

Can the roof take it?

A solar panel weighs roughly 20 to 22kg and covers about 1.8 square metres, so the load is spread rather than concentrated. Most roofs carry it without difficulty. Where there is any doubt, the answer is not a rule of thumb but a structural engineer: ask one to assess the roof and confirm the additional load is acceptable before work starts.

What the mounting system consists of

The Easy Plan system uses stainless steel hooks with adjustable height, which keeps the assembly watertight and makes it straightforward to fit. The parts are:

• Stainless hooks with a mounting plate for the rails
• Aluminium rails, 1200mm long
• Rail connectors for joining rails together
• Rail clamps
• End clamps and middle clamps

For flat concrete tiles, stainless hooks with a 180 degree bend suit the profile better.

A worked example: 24 panels on a new build

On a five bedroom Lavenham, a newly built property, we fitted 24 panels to the south facing side. The mounting used 180 degree bend hooks with extendable aluminium rails and 140mm rail connectors. The first two rows alone came to 6,560 watts of peak power, and the roof showed no load problems.