Green Building Forum - PV roof fixings through slate?

PV roof fixings through slate?

XT600 — Thu, 03 Oct 2019 20:32:20 +0100

I know this topic was done a few years back, but I wondered if anyone had any updated information or whether any new systems had been developed. I have a fiber-cement slate roof which has for some reason been nailed onto 19mm battens instead of 25mm. If I try to remove a slate with a slate ripper, instead of pulling out the nail it just splits the batten. With 32 hooks to fit it will wreck the roof! Does anyone know of a system that can be bolted, and weatherproofed, without removing the slates?

PV roof fixings through slate?

Mike1 — Thu, 03 Oct 2019 21:05:48 +0100

No - but you could look at installing an integrated tray system as an alternative. For example:
https://en.irfts.com/easy-roof-evolution/
http://www.gseintegration.com/en/InRoof.html

PV roof fixings through slate?

Peter_in_Hungary — Thu, 03 Oct 2019 22:08:32 +0100

Posted By: XT600I have a fiber-cement slate roof which has for some reason been nailed onto 19mm battens instead of 25mm.

Either availability or cost saving !

I Have a hacksaw blade holder whereby the blade is held at one end by a handle, with the blade inserted so that the cutting action is on the backward stroke. Would such a tool allow a blade to be inserted between the slates to cut the nails which would be much less violent that the action of a slate ripper

PV roof fixings through slate?

djh — Thu, 03 Oct 2019 22:39:53 +0100

Is the roof strong enough to stand the extra weight of the PV panels? And wind-loading etc. Has an engineer checked?

PV roof fixings through slate?

jamesingram — Fri, 04 Oct 2019 07:55:20 +0100

Nothing new I'm aware of. Theres the hanger bolts with self sealing washer and the slate hooks with sealing slate , that's about it.
I did a job a while back when there was a rush to installs before funding cut off date. There was a shortage of kit nationally and the client was happy to go with flat hooks screwed on top through to joists with sealing washers and pad plus addition ms sealant. I was dubious but as yet havent had a call back. The panels of course cover most the roof.

You could go with a quality in roof system like GSE, not greatly more expensive than a on roof system. Looks far better in my opinion.

PV roof fixings through slate?

tony — Fri, 04 Oct 2019 21:50:15 +0100

Solar limpets ?

PV roof fixings through slate?

XT600 — Mon, 07 Oct 2019 19:33:08 +0100

Posted By: Peter_in_Hungary
Posted By: XT600I have a fiber-cement slate roof which has for some reason been nailed onto 19mm battens instead of 25mm.

Either availability or cost saving !

I Have a hacksaw blade holder whereby the blade is held at one end by a handle, with the blade inserted so that the cutting action is on the backward stroke. Would such a tool allow a blade to be inserted between the slates to cut the nails which would be much less violent that the action of a slate ripper

Thanks, his maybe worth investigating, although I'm not sure a standard hacksaw blade will be long enough...

PV roof fixings through slate?

XT600 — Mon, 07 Oct 2019 19:38:01 +0100

Posted By: jamesingramNothing new I'm aware of. Theres the hanger bolts with self sealing washer and the slate hooks with sealing slate , that's about it.
I did a job a while back when there was a rush to installs before funding cut off date. There was a shortage of kit nationally and the client was happy to go with flat hooks screwed on top through to joists with sealing washers and pad plus addition ms sealant. I was dubious but as yet havent had a call back. The panels of course cover most the roof.

You could go with a quality in roof system like GSE, not greatly more expensive than a on roof system. Looks far better in my opinion.

I'm not keen on the idea of bolting straight through, unless something has been specifically designed for this purpose. I'm doing this job for a friend of mine, so it will need to be reliable long term! As for the in-roof system,I agree it looks good, but not so practical for retro-fit. I would still need to refit tiles around the perimeter and would end up with the additional hassle of disposing of all the old slates :-)

PV roof fixings through slate?

XT600 — Mon, 07 Oct 2019 20:24:45 +0100

Posted By: tonySolar limpets ?

Thanks Tony, these maybe the answer! :-)

Has anyone else here used them before?

PV roof fixings through slate?

jms452 — Mon, 07 Oct 2019 22:05:51 +0100

Our installation was very similar - installers response to my question was:

'Your slate tiles are usually all screwed individually to the roof battens so we cannot remove tiles without causing more damage so we were advised by our roofer to attach our Schuco aluminium brackets to the top of the tile by drilling the tile at the point where the batten is below and supporting the tile, then screwing through to the roof truss. The penetrations in the tile are then weatherproofed with a lead flashing that is lipped under the slate above to allow water to flow down and over the bracket.'

This approach has no issues 8 years later

PV roof fixings through slate?

jamesingram — Tue, 08 Oct 2019 17:27:41 +0100

Posted By: jms452Our installation was very similar - installers response to my question was:

'Your slate tiles are usually all screwed individually to the roof battens so we cannot remove tiles without causing more damage so we were advised by our roofer to attach our Schuco aluminium brackets to the top of the tile by drilling the tile at the point where the batten is below and supporting the tile, then screwing through to the roof truss. The penetrations in the tile are then weatherproofed with a lead flashing that is lipped under the slate above to allow water to flow down and over the bracket.'

This approach has no issues 8 years later

yep that works, I've done similar .

PV roof fixings through slate?

jamesingram — Tue, 08 Oct 2019 17:31:28 +0100

Posted By: XT600Posted By: jamesingram As for the in-roof system,I agree it looks good, but not so practical for retro-fit. I would still need to refit tiles around the perimeter and would end up with the additional hassle of disposing of all the old slates :-)

you might find the inroof sys actually works out quicker and cheaper,
The flashing will help at the edges but it does depend on where the array sits on the roof.
It is a belt and braces approach , the only other option seems drilling them and flashing each bracket

PV roof fixings through slate?

XT600 — Tue, 08 Oct 2019 18:08:57 +0100

Having looked at the Solar Limpet, I'm quite liking it. It now has MCS and BBA approval so surely has to be the best bolt through option?

PV roof fixings through slate?

tony — Tue, 08 Oct 2019 18:16:09 +0100

Be sure to follow installation instructions and use trained installer

PV roof fixings through slate?

jamesingram — Tue, 08 Oct 2019 18:18:40 +0100

Posted By: XT600Having looked at the Solar Limpet, I'm quite liking it. It now has MCS and BBA approval so surely has to be the best bolt through option?

they look very good, i wasnt aware of them ,
still involves drilling through slates, but I think they would be my choice over flashing with standard brackets .

PV roof fixings through slate?

XT600 — Tue, 08 Oct 2019 19:46:31 +0100

Posted By: tonyBe sure to follow installation instructions and use trained installer

I spoke to them today and they are happy to turn up on site and train me to fit them :-) Looks pretty straight forward for anyone with common sense and an understanding of roofing :-)