Slate fixings

[Worcester]

@powervan, thanks.

In materials that works out at £16 a mount, if the roof will take 1200mm between supports, that is a similar price to the mounts I use at 600 mm centres (including the lead).

as they say in the ad "Peace of Mind - Priceless"

 

[The Solar King]

Been away a few days so not able to reply until now.

@Gary M. You are right, an eyelet crimp would have been tidier. However the photo was taken for MCS inspection. I raised this point with my assessor and he was happy with this.

@Biggs Solar. Do you have a better way? We are happy with this because it overcomes the issue of drilling through slates. If you use a J Shaped bracket you still have to make that weather proof or mount it on top of a flashing in the same way. you would end up with a much bigger flashing. The spacing is every 800mm also exceeds wind loading according to Schuco data. (the info is all in German but Google translator does a great job). Remember Scottish roof with no battens.

@ Worcester. Yes I am happy this will last. The rest of the lead on the roof is now 22 years old and is in perfect condition. I should know, I built the house and still own it!

@ jerrials. I would go back and re-read the 3rd edition draft. This is what is actually says:

"Tiles or slates removed for fixing a mounting bracket should be re-attached to include a means of mechanical fixing.

Mounting systems on slate or tile roofs that rely on a fixing bolt through the tiles/slates are not recommended. This is due to the potential for damage to the slates/ tiles and the difficulty for ensuring a lasting weather tight seal.

Bolt through fixings systems that incorporate a rubber sealing washer (originally designed for metal roofs) are sometimes suggested as a way of ensuring a lasting weathertight seal on slate or clay tile roofs. However, due to the potential for cracking slates and subsequent worries over long term durability, this method is not considered appropriate in most cases. Only installations on large stone slate roofs, where the slat es are very large, thick and robust – are considered suitable for this method."

They are talking here about fixing through slates. What We have done is to remove the slate and install the flashing to overcome this very problem. It is re-slated around the fixing which is directly into the roof joist. (in this case also through the close boarding).

 

[SolarCity]

Sorry for criticising your install, SK. I just hate the idea of drilled holes and hanger bolts. I've not worked on a roof with no battens so I can see it is a difficult one.

 

[The Solar King]

None taken

It is actually very important to have the views of others. How else do we learn or improve?

The Install would look tidier without the Leadmate. The bolts are designed to seal using just the neoprine washer. The roofers who are experienced in leadwork suggested the sealant, so we went along with this. We all screw into roof joists as a matter of course. The difference here is the size of fixing. The roof joists are 150mm x 50mm, so are big enough to take the bolts. On an engineered 38mm truss I would be using noggins. The install is a single row of 15 Sanyos. Due to altitude and latitude, this meant 30 fixing points (15 per rail) to meet wind loading. You can be certain there will be no issues over pull out! Using the other system being discussed here may not be as cost effective. Unirac would be £480.00 plus rails and mountings . What we did cost £180.00 plus rails and mountings. This includes a roll of code 4 lead at a shade under £100.00. Both require the removal and refitting of slates, so labour should be equal.

If we get pressure on margins due to reductions in FIT, we all have to have cost effective solutions that still do the best job for the customer. If someone can come up with a cost effective system that also minimises the labour input involved, I'll be first in the queue.

 

[Worcester]

Cost effective: but would never condone it, in fact if I was building control I'd probably condemn this:

[video=youtube;jxdQnsFlGlg]http://www.youtube.com/watch?v=jxdQnsFlGlg[/video]

 

[SolarCity]

Surely there must be some pressure on the slates with this method?

 

[PvNewbie]

BiggSolar...I agree. I also can't see the special backing to waterproof it lasting 25 or more years!!!!!

 

[The Solar King]

Your having a laugh Worcester!
I cannot believe these people are taking themselves seriously. This is exactly what 3rd Edition draft is trying to avoid.
This could not be described in terms of a good outcome for the customer.

 

[Worcester]

@The Solar King,

It's not my install - I wouldn't have anything to do with it.

Just a video I found back in february 2011 when looking to see what others did on slate, and it worried me as I couldn't believe what I saw.

They are really serious and are really proud of what they are doing and that's worrying. - Just how many others have they done like it?

 

[grandfortune]

went to do 230v part of an pv install today, there i the biggest installers i think very professional, i asked how he fixed the panels as it was slate and i have one next week to install, they fix the hangers straight though the slate and lead the whole thing, i asked if that was right and they insured me is was, they have had varoius people look at it and said it was fine including MCS.?

cheers grand