Fixing to slate tile roofs

[beefheart]

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]

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]

@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]

@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]

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]

@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]

Hello fellow installers

 

[Eco Deal]

Sorry No close ups

 

[Easters]

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]

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]

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]

this is how we like to do itcode 4 lead dressed nice and neat, no cantilever effect on the slates,

 

[Worcester]

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]

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

 

[solarsavings]

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.