Fixing to slate tile roofs

SolarCity · Jul 18, 2011

I know this subject has been discussed many times on this forum but I thought I'd bring it up again seeing as I've got four jobs to do next week, all with slate tiles.

I was just wondering how other installers are going about it.

I'll let you know how I'm doing it and feel free to comment or criticise. Currently, I remove the slates where the bracket is to be fitted and lay down some lead. I then screw down a standard plain tile bracket. I then refit the slates apart from the one directly above or below the bracket. Another layer of lead is dressed in over the newly installed bracket. This doesn't actually look that bad. However, it uses a lot of lead and I'm wondering if there are any other methods that anyone has used.

I don't like the idea of drilling a slates although I concede that this may be an entirely watertight and professional way of doing things. The flat slate bracket baffles me. Being flat, I would assume that the bracket is fitted on the slate itself. Surely, if this is the case, the slate would be likely to break in years to come?

I'm interested to hear your thoughts.

BruceB · Jul 18, 2011

I am trying the flat slate anchors later this week for the first time combined with some lead. I'll let you know how it goes or whether a nightmare!

SolarCity · Jul 18, 2011

Are you planning on fixing the brackets on top of the slates or just sucking it and see?

Von Vardo · Jul 18, 2011

We lift the slates and flash around the brackets as you do but then cut the slate to fit around the bracket

BruceB · Jul 18, 2011

I am planning on removing the top slate then screwing the slate anchor all the way through the lower slate(s) into rafter but making sure the load bearing end sits on the slate above a batten in order that there is little or no bending moment imposed on the slate. Then some lead over the top of the anchor and then the top slate replaced with a notch cut out of it. There were some photos of that technique on here a month or so ago I think. Only 18 anchors to do on a small roof so hopefully a good one to learn on!
Regards
Bruce

Worcester · Jul 19, 2011

@BruceB You could also use a lead alternative, we have successfully used "IKO Flash lead free flashing" Product Page - IKO High Performance Roofing Systems on a couple if recent jobs, it took the roofers a couple of anchors to get used to working with the new material, however the job was well done and looked good. From the ground even on a bungalow roof you couldn't tell the difference. (p.s. it's 1/2 the price of lead)

SolarCity · Jul 19, 2011

That's interesting, Bruce. Does this not leave a very small area of the bracket actually screwed tight to anything? Just the part above the batten?

BruceB · Jul 19, 2011

@Worcester, yes, I noticed you mentioned that stuff a couple of weeks ago or so. I have got a roll of 8" wide thick sticky flashing (no name on it anymore) which I believe is similar and I was also going to try.

@Biggs, The screw holes in the slate anchors are at the up-roof end. The weight bearing end is the down-roof end. Hopefully both ends will be above or near battens. It should work if I am lucky with headlap, slate length, anchor length, batten pitch, but I acknowledge there are a few variables! I'll try to remember to take a few photos.

Regards
Bruce

SolarCity · Jul 19, 2011

Thanks Bruce, I'll be interested to see the pictures.

It would appear that there is no 'good' solution to the slate tile problem.

power7171 · Jul 21, 2011

Hi

I am going to be doing my first slate job next week and i am very intrested in how you lot get on with your jobs.

My only concere is when you remove the tiles and have fixed in the brackets how do you refix the last slate around the area you have removed.

Worcester · Jul 21, 2011

Ok, The boys at work, Anyone at the Segen conference in Sept, can by me a beer

http://------/SlateRoofInstall

BruceB · Jul 22, 2011

I said I would try to take some pictures of the slate roof I did yesterday and today. A small installation: 6 vertical rails, 18 anchors and 12 190W landscape panels. In the end it was straightforward enough apart from having to work in the rain much of the time. I have attached a file with some pictures (1MB).
Regards
Bruce

SolarCity · Jul 22, 2011

Thanks for sharing that with us, Bruce, its most appreciated.

I suppose the big issue with slate tiles is that many of us are electricians and haven't had much experience of them. I'm very windy about fixing brackets onto slates because I worry about where stresses will be exerted on the tile.

Pwee · Jul 22, 2011

good pictures and information. cheers for that mate.

MikeXl426 · Jul 22, 2011

Thanks for that Bruce

How did the brackets feel? Were they wobbly? I was wondering that if the wind lifted the bracket, the lower screw would act as a fulcrum and break the slate near the top. Did it feel secure enough to handle lift? I may be wrong but wonder if the slate would break under a lift load.

beefheart · Jul 22, 2011

personally there is no way i would be happy with that if i was a customer, as an installer even more, brackets on top of a slate slate is a no no full stop.how much much wind load and how much movement within the array do you think you will get, cantilever effect maybe?? maybe not 5 years but maybe??

BruceB · Jul 22, 2011

They felt very solid, the anchor screws are each side of a batten and with double lapped slate the top of the slate is resting on a batten so it is not going anywhere. Suggest a better option if you have one...............?
Regards
Bruce

MikeXl426 · Jul 22, 2011

@Bruce

Personally, I couldn't!

I've never done an install on slate but know it will come up sometime so am looking for ideas. Your contribution is excellent and I've wondered how these type of mounts are supposed to work. I've scratched my head many times looking at a sample bracket the same as you have in your pictures thinking 'how the hell is that supposed to work'. I now know as someone's had a go and been generous enough to share it. I can't see any other way the manufacturers intended it to work so thumbs up for making it clear.

Mike

Worcester · Jul 23, 2011

@BruceB Many thanks for that, I'm still not sure about screwing through, though with the method chosen you've done a good job, if I was to do it that way the only difference I'd do would be to use S/S coach bolts instead of screws.

I generally would have 2 concerns, the first is that whatever you do you are stressing the slate, vertical dead loads and a rotational wind load will stress the slates, the second is about using only 18 roof anchors to support 12 panels, the point loads applied to the roof expecially since you're applying the weight of two panels per rafter (6 verticals, 12 panels) is quite a high loading, and the wind uplift in the bottom corners will also be extreme.

If the calcs came out OK, then fine.

I would dearly like a mounting maunfacturer to stand up and demonstrate how it should be done and back it with the regs. (p.s. Paul, I'm still waiting for that info!)

BruceB · Jul 24, 2011

The holes in the aluminium slate anchors were only 6mm without drilling them out so those were the biggest screws I could use. They were well into the rafters. I take your other points. I normally spread the load over many more rafters using horizontal rails and a cruciform, but decided not to in this case. I could have gone to 4 anchors per rail which would have totalled 24, but 3 per rail meant 2 were quite near the ends of the rafters and the middle one was right over the purlin so additional rafter loads were actually quite small. It was a sheltered location rather than an exposed hillside so not particularly worried about wind loadings. I do wonder like you what it will do to slates after 5/10/15 years.
Regards
Bruce

Worcester · Jul 24, 2011

@BruceB,

Thanks for reply, and for taking it in the light that they are meant - to help others through this quagmire! My comments are there to try and establish a best practice for these types of install, I am still astonished that no mounting supplier has a definitive answer.

jockmac · Aug 2, 2011

Hello fellow installers

Eco Deal · Aug 2, 2011

Sorry No close ups

Easters · Aug 4, 2011

After 8 years Installing solar on roofs and hundreds of slate jobs I think this is the best method on slate.
The roofing installing the new Spanish slate said he was very impressed and was happy with the roof and it would not leak.

SolarCity · Aug 5, 2011

Easters, this appears to be the same kind of method that we use. We tend to keep the brackets a little higher above the slate to ensure that movement in the array doesn't stress the slate in years to come but this may be overcautious.

Bright_Light · Sep 19, 2011

So have you drilled and fixed through the slate and then flashed over the top? Or is the slate notched and fixings are direct to the rafter?

beefheart · Sep 19, 2011

this is how we like to do it

code 4 lead dressed nice and neat, no cantilever effect on the slates,

Worcester · Sep 19, 2011

beefheart said:
this is how we like to do itView attachment 7845code 4 lead dressed nice and neat, no cantilever effect on the slates,

Excellent example, and clearly no stress on the underlying slates - out of interest which brackets are those?

BruceB · Sep 19, 2011

And is there anything like a tingle holding the slate in place, or is it not necessary?

solarsavings · Sep 20, 2011

beefheart said:
this is how we like to do itView attachment 7845code 4 lead dressed nice and neat, no cantilever effect on the slates,

Do you have any photo's of the hook fixings.

beefheart · Sep 20, 2011

no tingle the slate is nailed back in, no slippage

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Von Vardo

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power7171

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Pwee

MikeXl426

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MikeXl426

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jockmac

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Easters

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Bright_Light

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beefheart

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