Fixing Solar Panels: is there a standard method?

[ToughButterCup]

How are solar panels fixed to a roof? 

 

I ask because I'd like to buy and install our PV after we have built the roof. I'd like to build the clips / fixing system into the roof  at the time we build the roof, rather than dig around in all that expensive insulation and waterproofing after it has been fitted. We are putting the rafters in in the next week or so, and that would be the time to install the anchor points for the panels

 

I have searched YT and found the usual nutcases: Watching most of the videos makes me wince - simple 8mm roofing screws screwed right into the roof with no regard whatever for water ingress. And people carrying heavy weights merrily waltzing around on a steeply pitched roof with absolutely no regard for safety

 

@Construction Channel (he isn't a nutcase) hasn't done his yet, so I can't watch what he's done. Hurry up Ed will you, please?

 

Are there any guidelines for attaching solar panels, any regulations I need to know about ?

[Russell griffiths]

I think a lot to do with your roof covering. 

Describe what you are having may help people answer.  

 

I will refrain from saying 4inch nails,oops 

[dpmiller]

why not in-roof?

[Construction Channel]

I'm afraid to disappoint you but I don't intend to be putting panels on the roof so I can't really help,

 

however I have worked on roofs with panels before so ill tell you what I can, 

the fixing system they used was very similar to the ones in the link except they connected to a rail instead of directly to the panel.

 

the lower z sectioned part is screwed to the rafters/ counter battens, then the black cover piece is tiled in like any other flashing, as long as they were in lines and under where the panels would go they just made them work rafters.  sorry I can't help more.  https://www.amazon.com/System-Modules-MageMount-Mounting-Magerack/dp/B06WRQMR6Y

[ToughButterCup]

1 hour ago, Construction Channel said:

I'm afraid to disappoint you but I don't intend to be putting panels on the roof so I can't really help,

[...]

 

Wha? 

'Snot fair. I need the video!

Ian

[ToughButterCup]

1 hour ago, dpmiller said:

why not in-roof?

 

Hmmm. 

In-roof, not sure what you mean. This, perhaps?

[Guest Alphonsox]

7 minutes ago, recoveringacademic said:

 

Hmmm. 

In-roof, not sure what you mean. This, perhaps?

 

Or the system shown on this obscure web site......

http://www.mayfly.eu/

[Jeremy Harris]

46 minutes ago, recoveringacademic said:

 

Hmmm. 

In-roof, not sure what you mean. This, perhaps?

 

 

Ian, I've just posted some photos in answer to a query by @Juj that might help with what the in-roof system looks like:

   You can save a fair bit of money on slates/tiles by doing it this way I found.

[PeterW]

All depends on the roof covering too - this is a decent video from one of the in- and on- roof suppliers. 

 

 

 

Edited April 4, 2018 by PeterW
2nd link wouldn’t show

[Onoff]

Say he goes for the in roof system but doesn't yet buy the panels. What does he cover the in roof trays with meanwhile?

 

 

[Jeremy Harris]

1 hour ago, Onoff said:

Say he goes for the in roof system but doesn't yet buy the panels. What does he cover the in roof trays with meanwhile?

 

 

 

I've been pondering this, and whether or not it would be possible to make up some cheap dummy panels as an interim measure.  They'd probably have to look reasonably good, but something like plywood panels covered with EPDM might do the job. 

 

 

[Construction Channel]

7 minutes ago, JSHarris said:

but something like plywood panels covered with EPDM might do the job. 

 

I like it, i was trying to think of a temp option and got as far as corrugated tin before I got distracted by sketch up. 

 

Epdm is a great idea. 

[SteamyTea]

Hooks that go under the tiles, unless slate, then it is threaded rods that go though the slate, or sometimes a thin plate that slides under the slate.

https://www.cclcomponents.com/schletter-roof-hook-universal?gclid=EAIaIQobChMImp7ui8Oh2gIVTzobCh0JngvQEAYYASABEgKCPfD_BwE

 

 

[Onoff]

And don't forget to integrate / anticipate your future cable runs or ducts for them into your roof construct even if not yet fitting the panels.

[ToughButterCup]

9 hours ago, Onoff said:

Say he goes for the in roof system but doesn't yet buy the panels. What does he cover the in roof trays with meanwhile?

 

21 minutes ago, Onoff said:

And don't forget to integrate / anticipate your future cable runs or ducts for them into your roof construct even if not yet fitting the panels.

 

There's a man who knows me well. 

 

Marry me?

[ToughButterCup]

I got a PM today from a member who pointed me in this direction  (thanks) : looks expensive, but on the other hand it's a high specification bit of kit.

Key thing about it is that (for me) this is the first company that I have found that takes both fixing and thermal bridging seriously

[Onoff]

1 hour ago, recoveringacademic said:

 

 

There's a man who knows me well. 

 

Marry me?

 

Let me think about it and you know how long that'll take!

 

You can't overthink things. 

 

[Gone West]

@recoveringacademic There are lots of videos to watch here. Don't know anything about the product though.

 

http://www.solarlimpets.co.uk/page4.htm

 

 

[ToughButterCup]

Thanks Peter.

Ian

[Russell griffiths]

Would this be a crazy idea

work out the area the panels would go in, then cover this section of roof with GRP, making an upstand and bonding in aluminium box section for the panels to fix to 

? or ?. ?

[Onoff]

Or a combination of ideas. A piece of ply battened to the thickness of a "standard" solar PV panel. Have some studs or brackets sticking out. F'glass the lot. Like a full dummy panel! Maybe it could be passed onto the next person.

 

But are panels a standard fitting?

[ToughButterCup]

27 minutes ago, Russell griffiths said:

[...]

work out the area the panels would go in, then cover this section of roof with GRP, making an upstand and bonding in aluminium box section for the panels to fix to 

[...]

 

Well, @Russell griffiths, it's the start of a thought process, almost exactly like the one I was brewing.  The spec for the under-panel area differs from the rest of the roof .

Under the panels = 

Fleece backed self-adhesive single ply roofing system(Alwitra Evalon VSK) or equivalent. To 15mm Promat Supalux sheathing

 

Elsewhere = 

Shingles treated with Non-Com fire retardant. Fix with stainless steel annular ring shank nails. Fixed to 25x50mm treated SW slating battens & counter battens on breathable felt, Klober Permo Forte or similar, to 15mm Promat Supalux sheathing.

 

Well how does that work then?  Have a look at this screen grab

 

The proposal is that in the area under the PV panels, fleece-backed Klober Permo Forte is stuck to the sheathing...... Seems to me to be in need of a bit more thought.

I mean how on earth is rainwater going to be dealt with once it has run down the panels? So the Permo Forte will need to be continued down to the guttering. Ok. But how far to the left and right of the panels? And how do we deal with the panels where they butt up to the roof light?

 

Making a proper tray for the panels to sit in and on seems to me to be a sensible way forward. And a waterproofing medium which is the same for the whole roof, under the panels or not.

 

How that tray (container) can be attached to the roof in a manner which keeps the thermal characteristics of the roof intact (or suffer interstitial condensation) is one thing.

How to keep it there so it doesn't get blown away in the wind is another.

And then, how do I keep the roof dry?

 

So far, this fixing system seems to be close to what's needed in terms of keeping the roof insulated from the fixings. Lets see what the company has to say and a quick peek at how much it might cost. Got a feeling it isn't going to be cheap.

 

[Jeremy Harris]

Two things are needed behind in-roof panels, and are essential.  The first is that there needs to be a membrane that's breathable yet allows any moisture that may get on to it (from driven snow and ice melt, for example to flo down to the gutter and not get through to the underlying structure.  The second is equally critical, there MUST be a ventilation path up behind the panels to the ventilated ridge.  The panels will get very hot and this ventilation is needed to reduce the temperature and get reasonable performance in hot weather.  The ventilation also allows the membrane to both dry off and allow vapour to permeate out through it, as designed,

 

For this reason we counter battened over the sarking, in line with every rafter (on 400mm centres, then draped the breathable membrane over the counter battens, so there was a ventilation space under it, then battened the whole roof at the specified slate nail pitch (with the lower row spaced closer), and then the in-roof plastic mounts were just screwed to the battens.  With either the Easy Roof or GSE system there are no fixings other than screw to the existing battens plus some wider boards fitted where required that are the same thickness as the battens.  There's no difference between the membrane under the panels and that under the rest of the roof:

 

 

I think the idea of covering the area where the panels are to go with sheet and then GRP or EPDM would work as a temporary measure, but might cost a fair bit.  Is there a way to buy just the panels now, and fit them, then get the inverter and house wiring done later, when funds allow? 

 

Probably worth asking around if anyone consider a two-stage process like this, and perhaps be OK with you fitting the mounting frames to the roof, as there is very little skill involved in doing this, the hardest part is making sure that all the mounting frames are fitted dead square and inline.

[ToughButterCup]

5 minutes ago, JSHarris said:

[...]

For this reason we counter battened over the sarking, in line with every rafter (on 400mm centres, then draped the breathable membrane over the counter battens, so there was a ventilation space under it, then battened the whole roof at the specified slate nail pitch (with the lower row spaced closer), and then the in-roof plastic mounts were just screwed to the battens. 

[...]

 

The architect was thinking about the difference 25mm would make to the way the house looks (not having counter-battens under the panels)

Stuff that. (For all the reasons you outline above)

 

8 minutes ago, JSHarris said:

[...]

 Is there a way to buy just the panels now, and fit them, then get the inverter and house wiring done later, when funds allow? 

[...]

 

The common-sense way forward. Thanks very much indeed J.

Right: got it clear in what's left of my frazzled brain.

 

Nearly Friday night. 

'S a bit of a marathon innit? Seem to be hitting 'The Wall' these days. If I cant take a joke, shouldn'a started should I?

[Jeremy Harris]

FWIW, I think there was around a 10 week gap between our panel frames being fitted and the inverter wiring etc being done.  Didn't cause a problem for the installer, they accepted that we were stuck waiting for the roofers to finish and for the cladding on the outside of the house to go on (as the inverter is mounted outside,on the wall  under the eaves at the North side, where it stays cool and is out of sight).