Solar PV Mounting

bill_on_line

Hi

Found lots advice on the forum and internet on Panels and inverters, however not much to be found on the mounting.

Made a few inquires and the installers all appear to use different mounting systems for a similar panel install including Hilti, Wurth, Tric and Schletter.

All appear to be made of alluminuim and stainless steel fixings which i believe is good for corrosion. I have concrete tiles and have seen a diagram were they have to be "cut out" to take the mounting for Wurth, which i am not sure about.

Also the cables need to be fed back into the roof, how is this done when the tiles interlock and to make it waterprooth?

Any opions and advice?

Thanks
Bill

rogerblack

bill_on_line wrote: »

Hi

Found lots advice on the forum and internet on Panels and inverters, however not much to be found on the mounting.

This is more a 'builder' question.
There are many ways to make it properly waterproof - from constructing an identical tile out of lead or aluminium or ... to - in some cases - using appropriate glues or sealants onto the existing roofing.

Exact details of how it's going to fix onto a roof will depend on the construction, with attention paid to the primary sealing - the tiles or whatever, to ensure that 99.9% of water goes down the tiles, and then the secondary sealing - tarpaper or whatever barrier is behind the tiles.
Then you need to consider thermal insulation and vapour barriers and ...

There isn't really a canned answer, as it varies so much.

Gizmosmum_2

Make sure you use a solar firm who employ roofers not people who can put solar panels on roofs. There are lots of scare stories of drilling through slate to install and using sealant to make it watertight. They all grind the back out of tiles, otherwise your rail would stick up where the hook was installed, as long as it's flashed back in with lead you'll still have a watertight roof.

bill_on_line

Hi Gizmosmum
Thanks for the advice. Like to known more about how flashing back with lead is done, maybe a google will deliver the goods?

Iain

bris

I am currently fitting the brackets to my roof, I have large concrete tiles and thought I would have to grind out the back of the tile. After I took off the first tile for the bracket I discovered at the top of the tile there is a hollow that the bracket fits neatly into. I need to take a small check out of the front of the tile but it's not big enought to need flashed. There is a ridge that runs down the back of the tile that needs about 10mm ground off so it sits back flush. I did my first three today and will start again tomorrow, weather permitting. I will take some photos at the different stages for you.
I too however will need to think about how to weather proof the cables, there is three strings in my system, so six holes to worry about. I think there are special solar cable entry products that you can buy, I saw one but it only took one cable and was 20 quid, Im certainly not going to pay £120 for six of these before I do a bit more research.

albyota

Cut a square in the centre of a tile large enough to take six cable glands,




lead (code 4) flash over the whole tile, drill six 20mm holes, and fit cable glands, tighten gland around cable....job done

Gizmosmum_2

Lead flexi slate is what most roofers that our clients use buy - available at any decent building suppliers, about £35/£40 + vat.

bris

Got a few more done today, start by getting the tiles off http://i7.photobucket.com/albums/y279/br1sha/2011-09-04110527.jpg
There may be a nail that need to be pulled out the just push up and lift off. http://i7.photobucket.com/albums/y279/br1sha/2011-09-04111021.jpg I need to take two tiles off because the bracket is in the way after it's checked out, the second removed tile gives the space needed.

Next fit the bracket to the joist, make sure you get the joist for a solid fixing, also note how the brackets I use have a bigger fixing plate that allows a bit of movement either side if it's not centre on the joist. http://i7.photobucket.com/albums/y279/br1sha/2011-09-04112655.jpg
Next up is to mark out where the check will be http://i7.photobucket.com/albums/y279/br1sha/2011-09-04112813.jpg
Cut out the check and grind the raised edge off the back of the tile so it sits back flush http://i7.photobucket.com/albums/y279/br1sha/2011-09-04113250.jpg
Slide the tiles back into place, make sure it's bang on the string line, this run has 7 brackets so a string line was crucial.

That was the easy run as it was low on the roof and could be done working from the ladder. I also got the smaller roof started, this was a bit more time consuming and not for the fainthearted, http://i7.photobucket.com/albums/y279/br1sha/2011-09-04184106.jpg

Weather permitting I will finish the rest or the mounting kit this week, It's very time consuming and could really do with a second person to help, I will have help all next week.

This is my first time working on a roof, it's not rocket science but but I am a very capable DIYer and have the confidence to climb onto a roof, please don't try it you have even the slightest doubt. Tie some webbing to the ladder with a belt hook to catch you if you slip.
Can I also point out that not many MCS accredited installers will come anywhere near you to sign it off if you do any work on the install, please bear this in mind before you start. I am lucky that an old friend is an MCS accredited electrician who will install all the panels and inverter for me and sign it all off.

Ps I don't know how to upload the photos dirsct to the site.

albyota

Bris, even though I took some risks when installing my panels, but at least I had a platform and hand rails /edge protection, without sounding like a busybody health and safety inspector, even though that appears to be a single storey roof, you are just as dead falling from that height as a two storey roof, no fall arrest, no platform or barrier and the ladder aint even tied off, hope your back on here to keep us up to date and not in hospital....or worse...:eek:

hope those screws are of adequate size to stop the array ripping the roof off in an 80mph wind!

god I sound just like me Dad.....:)

bris

Thanks for the concern, your right though, the ladder is not tied off, it's secured at the bottom though. I use a harnes with a safety webbing which hook onto a rung of the ladder, if I slip I should only travel 3 feet.
The screws are 5x90mm screwed directly to the joists, this is what was recommended to me, so I hope they are adequit, if not then I will need to start again. Don't fancy that.

bris

albyota wrote: »

hope those screws are of adequate size to stop the array ripping the roof off in an 80mph wind!

After a rethink, due to your remark about the screws, I decided to change them while I am still at the early stage and it's not to late. I have swapped them all over for longer coach bolts, hand tighened and they do feel much more secure. It only took 45 minutes as all I needed to do was push the tile up slightly to gain access to them.