mounting systems for welsh slate roof

[Markc]

He said he sell's lots of them and has known them to be used on a multitude of different roof structures. I mentioned the "big debate" on here and he wasn't surprised. It's in powering trust into the rubber washer which he said is the issue. Obviously from their construction they are designed to be water proof and be drilled through the finish roof structure. Can be used on slate, metal roofs, flat roofs and others. He recommended use on a fixed material rather than a movable one like pan tile. He also said other installers use the same method as described in earlier posts, so it seems its a case of having some faith in the product. An idea he put to me to sell it to a concerned client is to fix one though the bottom of a lunch box or Tupperware box as a sample and then fill the box with water. Seems a fairly easy thing to demonstrate..........unless it leaks!!!

I also questioned the issue on build regs on the size of the bolt. He did agree the 10% rule but hasn't come up against issues regarding that point so far. We discussed the possibility of applying additional timber to side brace the rafter and fix into that rather than the rafter itself. I will be seeing a build inspector next week on a different job so may ask the question to him and see what his take is.

My opinion now see it is, it looks like it will do the job. Still not looking forward to our first slate roof job but fortunately not to many of them are around this way.

 

[GPack]

Thanks Mark. Some fair points. I Like the idea of fixing a length of timber to the rafter to avoid issues with building regs. It'll be really interesting to see what the building inspector thinks about it. I think after that meeting you will have gone a long way to exhausting all aspects of this type of fixing and should be in a good position to advise future customers. Would love to know what he thinks.

 

[Martin Dawes]

Thanks for the pictures, Mark. I think it'll definitely be the method I use on our slate tile PV installs.

Regarding the 10% rule, it is possible to use bigger fixings but you must supply engineer calculations to prove that it won't affect the roof structure too much. We had to take this route on an unusual loft conversion where we had no choice but to drill holes for cable runs.

 

[JulianC]

Been looking into slate roof mounting methods again briefly today and found these hooks:
Solar PV roof fixing slate - £9.99 : Solar PV Systems, The Best Online Store
The benefit from my point of view is that we can standardise on the K2 mounting rails that we use for concrete tile roofs as they are part of the same range.

I am still unsure on the hanger bolts. Neat as they undoubtedly are, I can't ignore our roofer's opinion. Also just read that the flex inherent in the bolts (quite normal) can, over time, stress or crack the slates. Not seen any proof of this though. Oh, I dunno!....

 

[GPack]

Hey, I got my first call today to install a system. Went around to have a chat and take a look at its suitablity and came across asbestos slates. Like welsh slates but asbestos!
Any ideas if these are okay to work on? The building is an old cobb cottage. Chap says it may have had a thatch before these tiles were put on. I'm going to talk to a local roofer in a few days and will ask him what he thinks. Any one here had any experience with them. I can't believe having worked out how to deal with welsh slate I get interest from someone with asbestos slate! Unbelievable!

 

[JulianC]

Funnily enough, our first slate roof job was initially suspected to be asbestos tiles (householder thought they were). Our roofers went up and had a look and confirmed they weren't. However, had they been asbestos our guys would have had to have gone up 'suited and booted' and taken extra care of any waste (double bagging and taping etc) and all manner of other asbestos related H&S requirements. The slates themselves don't present any problems unless they're damaged, or get damaged during the course of the work. The upshot was the job would have taken longer and cost a lot more!

 

[GPack]

Hey MarkC. Would you mind telling me who your supplier is? I hope to get a few quotes from MCS accredited suppliers for a PV system. I was thinking about just sending out a quote request to all the suppliers and seeing what comes back. How did you go about finding your supplier? Also apparently the roof that I thought might be asbestos tile is cement siding. I think this is still a product that can be used legally but I'm pretty sure it does contain asbestos.

 

[Markc]

When it comes to the possible presences of Asbestos there is no other way in knowing than getting it tested. NO ONE can visually confirm the lack or presence of Asbestos and that statement came direct form a very good family friend who works with asbestos every day.

The cost of sample testing is so negotiable it isn't worth not testing. Better to know for certain than have a doubt over what some one said. If you are working on an Asbestos material you will have a duty of care over ALL the other occupants and trades working or being around that area so if its is discovered you were negligent in having a material tested you could find yourself in trouble. It is also the duty of the property owner to inform you of the presence of Asbestos if they know its there. As for removal of it, it must be done by a licensed contractor. Not a job I would perform myself. Not worth the risk.

As for my suppliers we use lots. Look about on line and call them, not just email, they all want the business and I found the call got more response than the emails. finding a good supplier is something you will have to put the leg work into as its as much about forming a working relationship as anything else.

 

[JulianC]

When it comes to the possible presences of Asbestos there is no other way in knowing than getting it tested. NO ONE can visually confirm the lack or presence of Asbestos and that statement came direct form a very good family friend who works with asbestos every day.

Depends on the circumstances. ie. from ground level impossible to tell, up a ladder - definitely slate. That's the extent of the testing our blokes did and it was enough.

 

[GPack]

Thanks for the help. I'll let you know how I get on.

 

[mitchelj00]

Hi all,

They can be found online from a Goggle search. They supply and install and have a eco education centre with a slate roof with PV on it. Worth a try.

 

[dansk]

Hi,

First post here - i cam accross this thread as im still not comfortuble with slate, ive done a slate roof and my way of doing it was drilling through and coach bolting an aluminium bracket with lead flashing over. I watch another companys website as they post photos each week of there jobs and on the last one it was slate and it looks like they use a pantile bracket bolted to the rafter and flashed over, they must cut the slate to fit.

 

[solar smart]

Welsh slate & yorkshire stone. The best way is inroof strip it and fit it but thats because i like the roofing aspect and that when i walk away from the install i know there will be no leaks in years to come and dont mention sealants on roofs as they dont work. If you need to use sealant you have not installed the gromit properly and it will leak in the future but if the anchor bolt is installed properly square of the slate and tightened down properly it will be ok. Thin brittle slate - you are better using the in roof kit but that could make you less competitive so back to plain tile brackets, lead flashed in and slate cut to suit.can give you pictures to see what you think just drop a line

 

[SolarCity]

Hi Solar Smart, I'd love to see those pictures if you've got them available?

 

[dansk]

me too please.

 

[buzzbuzz]

I drill a pilot hole with a 2mm drill bit and from the outside drill the hanger bolt into the joist!

I think this is a great idea for locating the position of the bolt. But one thing is confusing me....Do you drill squarely through the entire depth of the joist (4 inches, say) and then through the slate, or in through the side of the joist at an angle? It seems that you'd need a very long drill bit to drill squarely up through the joist and 2mm is a bit thin. Anyone got any ideas?

Buzz

 

[Pea Vee]

Mark,
We have just taken on our 1st slate roof install. OK with hanger bolts but where do you get the epdm rubber glands..?
Thanks,
Steve

 

[Worcester]

Check out what Baxi recommend for installing their thermal panels

http://www.baxi.co.uk/docs/Baxi_Sol...t_Plate_Solar_Collector_Mounting_36005977.pdf

If your going to use hanger bolts, this method satetment looks probably like the best you'll get. (Slate starts on page 12)
Now, why don't all the PV mounting system providers, panel makers, etc provide information as comprehensive as this?

The edpm rubber glands should come with the hanger bolts, - check with your supplier.

 

[pembrokeshire]

Lead looks ok

 

[Energetic]

I don't want to restart this debate but when using hangerbolts on a slate roof with no loft access, ie loft conversion, no visible rafters or nails at the facias, how does one find the rafters to fix to? You would need to be pretty accurate surely. Is there a scanning tool to locate them from above?

 

[pembrokeshire]

Not wishing to be piccy but really you need to know the size, spacing and condition of the rafters, to determine the anchor spacing at the time of survey. Can be a leap in the dark otherwise !!
You can strip a section to have a look , better safe than sorry
Mark

 

[SRE]

Are people really using hanger bolts for slate roofs????????? Unfortunately 70% of our roofs are slate and we'd never use hanger bolts, our roofer and customers would be horrified. MEP - there's a knack for walking on tiles, roofers have learnt through bitter experience others haven't. Employ the appropriate trade and you'll have a few cracked slates ( we did a Spanish slate roof yesterday - known to be the most brittle. 4kwp install 10 broken tiles replaced) do it yourself and you'll have loads more even if you're 8 stone wet through

 

[sre2011]

unirac sounds good but if all else fails you cant fall of with lead slates dressed over the brackets, like martin says not pretty but totaly hidden by the array and in my opinion weather proof is better than pretty, theres a training company in york who run a good panel instalation course covering all scenareo's

 

[sparkesroofing]

These bolts are NOT good!. As a roofing contractor for many years with about twenty installs under my wing i would not recommend the use of these bolts. Drilling holes in slates without the correct knowledge of how to make the penetration water tight doesnt make good sense to me. When the EPDM washer and roof bolt fall dead in between two slates, there is no way that the washer can make the penetration in the slates water tight. If you have to use these bolts then i suggest that you get either a roofer or plumber to make a lead slate similar to a siol pipe flashing and use the EPDM washer to seal the top of the pipe upstand, the other way is to use a roof hook and cut the slates around the hook and flash with a piece of lead, then cut slates around the top of the hook to create a neat and tidy finish.

 

[TheMightyGusset]

Check out what Baxi recommend for installing their thermal panels

http://www.baxi.co.uk/docs/Baxi_Sol...t_Plate_Solar_Collector_Mounting_36005977.pdf

If you're going to use hanger bolts, this method satetment looks probably like the best you'll get. (Slate starts on page 12)

Hi guys, I was reading this thread with interest, and my contribution was going to be to post that Baxi article, as it does seem to be the most comprehensive set of instructions out there.
Nice to see I've been beaten to it !

 

[Ramjam]

There is no need for lead on a slate roof if you do it properly, position the right brackets correctly and you'll be able to cut them perfectly to make a weathertight seal that is almost invisible. When I get a chance I'll photograph the process. It's a bit like one of those ornamental puzzles but when you get it then it's easy!

Hanger bolts excerpt pressure down on the slate to make the seal. slates are very weak in that plane and will crack, if not immediately then at some point down the line. Hanger bolts are for tin roofs! I wouldn't want to be one of those installers who's put loads of systems up with hanger bolts, time to close the company and re-open with a different MCS or you'll catch the warranty claims further down the line.

 

[TheMightyGusset]

There is no need for lead on a slate roof if you do it properly, position the right brackets correctly and you'll be able to cut them perfectly to make a weathertight seal that is almost invisible. When I get a chance I'll photograph the process. It's a bit like one of those ornamental puzzles but when you get it then it's easy!

I'm definitely interested in seeing what method (and brackets) you use.
Slate is tricky stuff to work with, so anyone who has any neat tricks please pass them on.
I like the Baxi method, purely because it's a neat and simple solution, and as Baxi are hardly a tinpot fly-by-night concern, then their I'd think that their method is certain to meet with approval from any certification body.

 

[Andrew Picton]

Not possible in our experience...love to see the photographs.

 

[dansk]

me too

 

[TheMightyGusset]

Another alternative might be the Unirac two-piece standoff and flashing solution :

It doesn't look the easiest, or cheapest, method, but might turn out to be the most robust.

 

[simon1982]

I use a thick aluminium roof anchor, fix the anchor flat to the top of the slate over a rafter carefully drilling through the slate with a masonry bit with the hammer drill-action turned off (like you would a ceramic tile). Sandwich a flash-band pad between the slate and the anchor and use lots of roofing sealant (from the roofing supplier) Use your favourite coach bolts and don’t over tighten. It helps to make your cable entry first then you can measure off from the inside and find the rafters from the outside. You’ll defiantly need a slate ripper, to replace Brocken tiles and you’ll need at least two good roofing ladders which you may have to modify with extra padding to protect the sates.

 

[TheMightyGusset]

Let's see if this works.
I've uploaded a Unirac pdf onto Google Docs that shows their 2-piece standoff and flashing solution :
https://docs.google.com/viewer?a=v&...2UtNTgyNWEyZTFkZDZl&hl=en_GB&authkey=CO-egt8G

 

[SRE]

Sorry, still not convinced - 70% of our jobs are slate - we'd never drill them. Just building problems a few years down the line.

 

[simon1982]

I have pictures if you're really interested, I live on the Dartmoor national park all the local installs are on slate roofs. It's a really unpleasant task but it works a lot better than you would imagine. We’ve never had trouble with leaks on slate installations because they’re so much easier to seal up.... You can still give me a tiled bungalow any day !!

 

[simon1982]

How do you go about it SRE ?

 

[SRE]

We're in a national park too, on slate roofs - agree with you about the tiled bungalows, urban installers don't know they're born ;-). Our roofer just takes the slate out fixes the hook and flashes it all back in with lead. None of it a problem just more time consuming and a bit of extra cost for lead and replacement slates. The only problem we've had was with cambrian slate which gave us problems with the hooks and flashing it back in. I wouldn't expect you to be having problems with leaking after such a short period, it's after a few years of the slate moving with the wind that the leaks wil appear and need to be resolved. None of our customers would let us near their homes if we were drilling through the slate.

 

[simon1982]

You don't find many properties in urban locations where the builder has used pine trees as rafters which seems to be very common here specially in houses built just after the war As a family we've been installing solar products on our houses we have built since the 90s, no problems yet. Thankfully.

 

[Worcester]

Time to share the photo's guys!

 

[TheMightyGusset]

Time to share the photo's guys!

I've been trying to !
Well, I've been trying to post some images, and a link to a Unirac solution, but my posts are awaiting approval from a Moderator.
I assume it's because I'm a Newbie.

 

[Worcester]

@TheMightyGusset

Why not load them up to http://picasaweb.google.com/home or Image hosting, free photo sharing & video sharing at Photobucket or Welcome to Flickr - Photo Sharing and then share the album tada! (just give us the link )