Noisy clicky corrugated metal roof- please help!

[jakeR]

Hello,

I have been doing a refurbishment of a 1980s timber framed house and have replaced two roofs with black 13/3 corrugated steel. I'm very pleased with how it went and how it looks, however... it is noisy! I was warned that it would be louder in the rain but it is not that significant and I quite like that sound. It is, however noisy when the sun hits it and there are pops and clicks all over the roof, I think caused by thermal expansion. I would expect this to happen a bit but it really is very noticeable and when there is intermittent sunshine it happens a lot. One of the roofs is a (celotex) warm roof and so the noise of this travels inside quite effectively. I'm supposed to be cladding some of the walls in the same corrugated steel but am loathed to do this until I've figured out how to mitigate this. A bit of googling suggested that it may be do with the fixings being overtighted but I just had a roofer look at it and he thought they looked fine. Anyone had any experience of this or have any suggestions about how I might be able to fix it? Painting it all white would help I guess but I really don't want to be doing that!

 

For context the layup of the warm roof is:

Corrugated steel fixed with 65mm BAZ screw from Cladco

45x70mm timber batten

breather membrane

45x70mm timber counter batten

200mm PIR insulation

Alutrix 600 vapour barrier

18mm Plywood

original 38 x 100mm timber trusses

 

The cold roof is the same but minus the PIR vapour barrier and plywood deck.

 

Any help would be very much appreciated. Thank you.

 

 

 

 

 

 

 

 

Edited 23 hours ago by jakeR

[Spinny]

Maybe you can try to identify exactly where the noise is coming from, does it eminate from the fixing points, or the overlaps, or movement against the battens etc ? Not sure how you do that, but maybe you could rig up a test piece at ground level replicating the roof structure, then apply heat ? Maybe you could photograph/measure the sheets/fixings etc  when cold and hot in different places ?

 

I can only say plumbing felt helps a lot with noise from copper plumbing/heating pipes expanding and contracting as they get hot and cold. They eliminate the friction between the pipes and the joists they pass through. So if you could identify the exact source, you might be able to insert some felt or other material which allows movement without noise

[Tom]

Stick a load of PV panels on it? 

[Bramco]

We don't get clicks but we do get bangs as the metalwork heats up. But they aren't often and aren't that loud, more a boom than a bang. So it does't really worry us.

 

The bangs and your case clicks can't surely be from expansion across the corrugations, so must be from expansion along the sheets. Our roof is screwed onto horizontal battens. So maybe there's play in the battens which takes up enough expansion to only occasionally have to jump and cause the bangs.

Part of our build also has the walls clad in crinkly tin. Again the sheets are mounted vertically across horizontal battens.

 

It would be a shame to have to demount what's already installed but the idea from @Spinny might be worth trying. If you do, do a test, then to really check things out, you'd have to do it with a sheet the same length as your roof and with a similar build up of at least the external part of the roof, otherwise you wouldn't be sure.

 

Another thing to check might be the screws and washers - we used EJOT low profile screws. See the attachments.

 

Hope you get things worked out.

 

JT3_FR2_4_9_timber range.pdf JT3-FR3 range.pdf

Edited 21 hours ago by Bramco

[Mr Punter]

If you have a 50mm layer of rockwool compressed under the sheets it helps a lot, but you would need to take the sheets off and refit.

[jakeR]

Thank you for the suggestions so far. It's hard to tell exactly where the noises come from but my best guess is that it is from where the sheets overlap each other, as standing on the overlaps can produce a similar sound. There are some sheets that overlap quite a bit so that i didn't need to cut down the length of the sheet, which may also be an issue. Maybe a test setup is required...

I'm also wondering if it could be to with wind as there is currently a lot of airflow as I haven't done the soffits or fascias yet- (there's a bit of pressure to move out of my mother-in-law's house and into ours so was hoping to leave this till later!)

 

 

16 hours ago, Mr Punter said:

If you have a 50mm layer of rockwool compressed under the sheets it helps a lot, but you would need to take the sheets off and refit.

I did wonder about this @Mr Punter but could this cause condensation problems for the timber or the roofing sheets? Would the rockwool be laid on to top of the horizontal battens and the tin on top? I wouldn't mind refitting them if it would help.

 

Thanks

[Tom]

48 minutes ago, jakeR said:

Thank you for the suggestions so far. It's hard to tell exactly where the noises come from but my best guess is that it is from where the sheets overlap each other, as standing on the overlaps can produce a similar sound. There are some sheets that overlap quite a bit so that i didn't need to cut down the length of the sheet, which may also be an issue. Maybe a test setup is required...

 

 

If you think it's where the sheets overlap you could run a strip of roofing membrane in between the sheets at these points (cut just shy of the edges so you don't see it. This might allow some slight movement between the sheets without the noise.

Actually, thinking about it, when we put our sheets on the roof (same as yours, 13/3 black corrugated) we used a mastic strip where they overlap to effectively stick them together but allow some movement. Did you do this? Our roof isn't that noisy at all, though we do have a ton of PV covering most of it.

[Bramco]

1 hour ago, Tom said:

we used a mastic strip where they overlap to effectively stick them together but allow some movement

 

I think our architect specified this as well - can't find the specs on this that he sent through to the roofer - I'll ask him if he can resend it to me.

Also worth checking suppliers sites like Cladco, to see if they have any useful pointers.

[Bramco]

Quick answer from our architects (he's our son, so needs to watch out on the inheritance front...)

The go to organisation is -> The Metal Cladding and Roofing Manufacturers Association (MCRMA)     Surprise, surprise.

And the answer is mastic or butyl tape.  See the attachments.    (Anyone reading this in the future should probably check to see if the guidance has been updated.)

 

GD19-MCRMA-sealants-guidance-document-1.pdf GD26-Aluminium-fabrications-executive-summary-1.pdf GD37-Sealing-of-end-laps-in-wall-cladding.pdf MCRMA-TP6-v1.pdf MCRMA-TP16-v1.pdf