Solar panels on roof - 35 degrees - planning and b/regs

[Alphatiger]

Hi, please see attached highlights. For England the optimal solar panel angles are 35 degees. I know no planning is needed if the panels stick out 20cm max , but based on these 1m panels on frames they will stick out 58cm at this angle. They won't be visible from the front street level if you look at how they're planned to be laid (there is a college on the back of the house with tall trees, so not visible for them). Do you think this will pass as I'm trying to be green?

My 2nd question relates to wind-factor for these - is there a paragraph in building regs, or will the inspector not bring this up (apart from weight/beam-strength issues)?

 

[rssteve]

How do you plan to fix them down. Just with ballast or actual fixings through the roof. I'd be worried if just ballast all the way up there. Usually the installer would do wind loadings as part of there design, or are you just installing yourself and not registering for any SEG payments?

Have you looked into the difference if they were only at 20deg?

 

[Alphatiger]

Thanks for your reply. 35 degree is the optimal angle if you see as attached. 20 degrees is 4% less efficient but I'd rather try to be 100% efficient if possible. In case anyone ask's why I don't place them on the front pitched roof, that will already be done without the need for planning.

The ballast (aluminium triangular frame) is planned to be bolted down through the dormer roof's OSB3 board to the roof joists.

The scaffolding will be up when the dormer will be built so I thought it will be a DIY job - trying to avoid solar firms charging 2k inc vat for this, but I guess I won't then be eligible for 25yrs of SEG payments : (

 

[rssteve]

For the sake of 4% I would rather have the panels alot more discreet and no chance of comeback. Is it a warm or cold roof, I guess if it's a warm roof having bolts through to the inside will make a cold bridge through the vapour barrier? If your not going for payment you might find the solar is more financially benefiting if the panels are pointing east and west, unless you are at home in the middle of the day and all your electric consumption is over a 2-3 hour period.

 

[big-all]

you will also greatly reduce wind loading if you half the angle
[i assume you own the building and the freehold assuming its a flat ??] edit this part not applicable as i have read your earlier comment
also if that drawing is accurate at this time off year with the sun low in the sky you will get shadows from the panel in front

 

[Alphatiger]

Ok thanks understood, it's a freehold house's dormer roof. Ok I appreciate there needs to be gaps between the 3 rows of panels to minimise shadowing.

 

[^woody^]

From that drawing it looks like most of the panels will be in the shade of the one in front for much if the year.