Any reason why I cant use a ~400mm wide strip of ply at the bottom instead of the three battens? The bottom of the trays basically abut our flat roof and I'm getting the roofer to extend his flashing up 300mm, the trays will then overlap, and there will be about 100mm from bottom of the tray to the valley.

 

Rough mock up below, nb piece of ply is only 250mm or so. The trays extend beyond the entire length of the flat roof valley.

 

Edited July 1, 20215 yr by Conor

we used 6x1 treated rather than multiple battens

I may come round for a nosey @dpmiller but I think your scaffolding is all down?

13 hours ago, Conor said:

Any reason why I cant use a ~400mm wide strip of ply at the bottom instead of the three battens?

I'd say go for it. 

GSE could simplify their instructions a lot by saying just make sure there are battens placed for fixing the trays, battens for fixing the panels and couple extra at the bottom for the flashing.

 

Does this help @Conor?

 

Cheers. Glad to see I'm not the only with a weird and complex PV panel installation!

Oh yes. And you don't quite realise just how much real estate is taken up by panels, trays, and flashing.