Solar PV on flat garage roof?

[Allan]

Following on from the Solar PV panel thread (very useful info, thanks to all contributors), I don't have a south-facing roof. However, I have a flat garage (felted) roof which would be well positioned. Is it possible:

(a) that there are solar panels that come with stands so can sit on a flat roof

(b) that the roof be strong enough to hold solar panels (or would it have to be reinforced which would probably blow the economics out of the water) (the roof is strong enough to walk across carefully for occasional inspection purposes; 1980s build)

TIA Allan

[John Williamson]

Yes.

You'll need to either provide the sizes and spacing and condition of rafters, condition and construction details such as the type of covering (Plywood, planks, thickness and number of layers of felt....) and the span, or (preferably and strongly recommended) get a proper structural survey done, which will require clear access to the underside of the roof, with no ceiling in the way, but will only take a few minutes with clear access.

The answer is a definite maybe, depending on what panels you use, and the roof design and condition. It may be, at 20 - 30 years of age, your roof is due for replacement anyway, depending on the maintenance that has been carried out.

[Chris J Dixon]

Yes, the installers will have suitable kit to do this. It would probably be outside the limits of planning "permitted development"(1), which would mean putting in an application.

It may well be the case that Building Control should be involved. At the very least, you would need them to confirm in writing that they were content for you to proceed (2), otherwise a formal application would be necessary.

(1) The limit is 200 mm above the roof, except for Scotland where they can be up to 1 metre above a flat roof, but not within 1 metre of the edge.

I made it a condition of accepting my installer's quote that they supplied written evidence that Building Control were content, before work started. If it had gone to a full application, they would have dealt with it, simply passing on any statutory charges.

Chris

[Bob Minchin]

Allan, If you want to 'decode' my email address and send me a mail, I can send you a document with info on the effect of efficiency of PV panels when used outside the optimum angle which is 30-40 degrees elevation.

Bob

[Chris J Dixon]

If you have a look at

you can personalise your location and most other criteria, and see how this influences the output.

Chris

[Man at B&Q]

Is theh garage attached to the house? Could the hopuse wall be the anchor point for the higher edge? could the roof be replaced with a stronger sloping one?

Why do you want solar PV?

MBQ