Flat roof mounts

SD_DRACULA · 20-05-2024 6:26pm #1

Anyone got experience with them, which is good/bad etc?

I don't like any of the ones with rocks/ballast, too heavy as it's a wood frame building and about 5 degrees slope

The finish is resin & fibre glass so I don't see why I can't screw the rails directly into the battens with a bunch of these https://midsummer.ie/buy/fastensolpitched/F-HB-WP ? And they seem adjustable too so I can change the angle a bit too

10-10-20 · 20-05-2024 10:28pm

Hi ya, is that into a residential roof now or an out building? I wouldn't be a fan of perforating the external finish on any flat roof at all. Plus it seems to imply that these are for corrugated roofs rather than flat... ?

Bolts are suitable for fixing mounting rail to metal or corrugated cement roofs with wooden supports.

SD_DRACULA · 20-05-2024 10:52pm

Residential, I know they aren't bespoke made for such a roof but just thinking of what "could" work

SouthWesterly · 21-05-2024 10:20am

Try the valk3box.

The other thread on ground mounts had links to valk systems

SD_DRACULA · 21-05-2024 1:05pm

Found this

https://www.nicholsonsts.com/articles/installing-solar-panels-on-grp-roofs/

which seems to be specially made for these types of roofs but I really doubt I will find stock in Ireland for it

SD_DRACULA · 21-05-2024 2:07pm

https://www.boards.ie/discussion/comment/122164244#Comment_122164244

This is crazy weight added to the roof, 120kg per panel so 720kg of just tiles plus another 120kg the panels. If it wasn't timber frame it would be ok and I'm sure if can take it of course but I wouldn't want the extra stress on the roof.

And these fibre glass roofs are also very smooth, I'd be worried the panels sliding off.

BobMcBob · 03-06-2024 8:00pm

I have a single ply membrane warm roof and emailed the manufacturer for a solution, they sent me the brochure,

Problem is I can't get a solar panel installer to use it ll, either they've not replied , or they want to use a ballast system, which I'm not sure would be great for the insulation. Also since I have 3 phase and want to use a DIY battery I am struggling to get it sorted

FATRA IFP Installation Instructions.pdf

10-10-20 · 03-06-2024 8:42pm

https://www.boards.ie/discussion/comment/122216627#Comment_122216627

Unfortunately if the installers don't have certification or even faith in installing the product then they aren't likely to want to install it as they'll potentially be liable for any future leaks. Try contacting the manufacturer and see if they have approved installers in Ireland.

SD_DRACULA · 03-06-2024 8:55pm

https://www.boards.ie/discussion/comment/122216627#Comment_122216627

I actually quoted that system for myself and if you want a laugh here's the price:

I think 28 pieces is overkill, probably only need 12 realistically, 3 per rail times 4 rails, even then it's mad expensive.

Spoke to the roofer that laid down the roof down for me and he says the roof hanger bolts should be fine as long as they're screwed into the rafters, these ones https://catalogue.k2-systems.com/hanger-bolt-solidrail-m10/2000122

BobMcBob · 04-06-2024 8:21am

That's good to see a quote, not so good on the price!

The hanger bolts look good, but the description states fibre cement roof. So no good to me, it was hard enough to get house insurance with my roof, I suspect that I would not be covered unless I used the proper system.

Looking at your quote I think I will have to start getting information on compressive loads on insulation and the weights of the ballast used

SD_DRACULA · 04-06-2024 9:55am

https://www.boards.ie/discussion/comment/122217663#Comment_122217663

Think I had a look at the ballast/bricks option and it was basically adding 120kg per panel on top of the roof, + panel and mounting system weight, not a fan of that.

conor_mc · 05-06-2024 8:49pm

The ballast calculators are a bit over-engineered imo, certainly at 120kg per panel! wind deflection etc. can play a big part, so putting say east-west panels back to back in a tent shape is more streamlined than all panels facing the same direction with exposed undersides.

SD_DRACULA · 05-06-2024 9:58pm

https://www.boards.ie/discussion/comment/122224450#Comment_122224450

Let's not forget that grp roof is basically an ice ring in terms of slippery

conor_mc · 05-06-2024 11:13pm

Fair point. Wonder if there are other ways of increasing the coefficient of friction besides increasing ballast?

...Ghost... · 06-06-2024 12:39am

I'll be installing 4-6 panels on a flat grp roof. Was also considering hanger bolts, but it I really wanted to avoid putting bolts through the fibreglass, I could look at running a couple of custom made metal rails from parapet to parapet. Do you have an outside the box method to mount panels without disturbing the fibreglass?

DC999 · 06-06-2024 2:35pm

https://www.boards.ie/discussion/comment/122225048#Comment_122225048

Could you somehow brace the ballasts to the side wall off the house? That's assuming there is another storey of the house above the flat roof. Then you won't have holes in the flat roof, but would in the wall as you would for any other fixing like gutters, satellite dish….

SD_DRACULA · 06-06-2024 9:03pm

I was thinking that alright, a 3.6m rail would basically cover the width of the roof and maybe then I could come up to meet it with a vertical rail from where the fascia will be.

Problem I see that there is no support in the middle

(roof not painted yet just resin)

The K2 rail system also has climber rails so could make a box out of them, run the rails in landscape and portrait and then panels on top.

I did a test with one of the hanger bolts, through an osb sheet and it makes a very nice seal I must say, pilot hole of 7mm through the rafter and 14mm through the osb (though it wouldn't hurt to fill it with silicone as well)