Noise from GRP flat roof

[ajs1954]

About 3 years ago we had a cold deck flat roof built onto a new extension (approx 35m sq). The roof is constructed of OSB T&G board with a grey GRP coating.

From the outset we have had creaking and banging noises from the roof that coincide with rises/falls in temperature, the problem being mainly restricted to the warmer months of the year.

We have checked the plastic fascia and guttering and even had expansion joints retro-fitted but the problem persists. Windy weather is not a problem (unless it's hot).

Our builder and roofing installer are at a loss what to do next.

The GRP looks in good condition (no lifting or bubbling)

Any ideas on how we can resolve this?

Thanks

 

[catlad]

They do sell expansion joints for grp roofs.

 

[dilly]

Osb t&g is very stable so there should be very little expansion in it,on a35sqm
Roof there is no need for expansion joint.It will be to late now to be able to tell but have they put enough fixings in to deck and at the right depth,ask builder/roofer how many fixings and type they would put into a board,any expansion should be on the perimeter of the roof and not butted up to the walls.

 

[UselessMan]

Hi, have you had any luck with your problem. I have exactly the same issue, and noted that there is another report "I had the extension built 2 years ago and opted for fibre glass instead of felt roofing because it has a longer life span.Trouble is i am getting the most unbelievably loud banging noises coming from it.The manufacturers ,Topseal, have been of little help and I cant find much on the net. "
My supplier hasn't been able to fix it. The noise has been awful on many days so far this year.

 

[ajs1954]

I'm afraid not.

We had a professional survey carried out and although some concerns were expressed over the quality of the bracing and the connection of the timber-work to the wall plate he could only come up with the recommendation that the roof be replaced with one of warm deck construction with a felt or epdm finish, the aim being to dissipate more effectively the thermal "shock" on the outer surface.

Having got quotes, we are also looking at converting to a pitched roof as this is only slightly more expensive and has a much better cosmetic finish than a flat roof. Our original construction was a "family project" so the work was not done entirely at arms length. If we had experienced the same problem with a third party we would have probably taken legal advice by now.

Is your roof a cold or warm deck construction?

 

[muks11]

UselessMan, do you also have a cold roof construction?

 

[UselessMan]

I'm afraid not.

We had a professional survey carried out and although some concerns were expressed over the quality of the bracing and the connection of the timber-work to the wall plate he could only come up with the recommendation that the roof be replaced with one of warm deck construction with a felt or epdm finish, the aim being to dissipate more effectively the thermal "shock" on the outer surface.

Having got quotes, we are also looking at converting to a pitched roof as this is only slightly more expensive and has a much better cosmetic finish than a flat roof. Our original construction was a "family project" so the work was not done entirely at arms length. If we had experienced the same problem with a third party we would have probably taken legal advice by now.

Is your roof a cold or warm deck construction?

I believe that it is a cold deck. The supplier has tried fitting 'mushroom' air vents on the roof, but it made no difference. No-one seems to be exactly sure what part of the roof is making the noise. The grp cover on the roof is slate grey, so they are going to paint it wet when the weather is dry to see if that has an effect.

 

[ajs1954]

Our roof is light grey (it looks nearly white on google earth). We discussed the use of solar paint with our GRP installer but he was reluctant to go down this route as he was unable to confirm it's suitability on a GRP surface.

He was also unwilling to continue with the guarantee if the gel coat was painted (and he would be the one who applied the paint!)

Not much help I know and it only serves to complicate further an extremely frustrating situation.

 

[UselessMan]

Our roof is light grey (it looks nearly white on google earth). We discussed the use of solar paint with our GRP installer but he was reluctant to go down this route as he was unable to confirm it's suitability on a GRP surface.

He was also unwilling to continue with the guarantee if the gel coat was painted (and he would be the one who applied the paint!)

Not much help I know and it only serves to complicate further an extremely frustrating situation.

It is! I meant to say 'paint the roof white (not wet)', but I don't expect it to work. I am now aware of 3 of us with this problem, in Leeds, Sussex, and myself in Hertfordshire, and no-one seems to be fixing it, and I can't find a governing body that shoudl be concerned about it. My supplier has tried to fix it, and has promised to keep trying. It would be nice to fully understand the problem. I'll keep searching for help.

 

[Xenon]

GRP does not have the thermal expansion abilities of a proper roof, it should be installed on a slip layer. Give it a few years and it will fracture, because its ****.

 

[UselessMan]

GRP does not have the thermal expansion abilities of a proper roof, it should be installed on a slip layer. Give it a few years and it will fracture, because its s**t.

Thanks. Thermal expansion and slip layer are new terms for me, so I will be looking them up. My supplier has given a lifetime guarantee for the roof, but I would rather not have something that can fracture.

 

[Shedsman]

Interesting thread - which lets me know that I am not alone - you can add Dorset to the list! We have a new extension which has a large (35 - 40 sq m) GRP flat roof with a 3 meter by 1.5 meter lantern in the center. This roof makes a lot of very loud bangs and cracks! It seems to me that this must be caused by the GRP covering itself since the noise occurs almost immediately the sun hits it. My builder is unsure of the reasons for this and is asking those who should be 'in the know' I will post here if I get an answer...

 

[UselessMan]

Interesting thread - which lets me know that I am not alone - you can add Dorset to the list! We have a new extension which has a large (35 - 40 sq m) GRP flat roof with a 3 meter by 1.5 meter lantern in the center. This roof makes a lot of very loud bangs and cracks! It seems to me that this must be caused by the GRP covering itself since the noise occurs almost immediately the sun hits it. My builder is unsure of the reasons for this and is asking those who should be 'in the know' I will post here if I get an answer...

Thanks for your response. My roof was painted with reflective white paint yesterday, and I'll let you know if there is any improvement. Are we allowed to communicate with our own email addresses? I am now aware of 5 people with the problem, but need to get updates on what they try, and if they get any success
Cheers
UselessMan

 

[muks11]

Also watching this thread with interest. My build starts in a couple of weeks and I've specified a warm roof with GRP.

Question for all of you. Do you all have COLD roof or WARM roof construction?

 

[UselessMan]

Our roof is light grey (it looks nearly white on google earth). We discussed the use of solar paint with our GRP installer but he was reluctant to go down this route as he was unable to confirm it's suitability on a GRP surface.

He was also unwilling to continue with the guarantee if the gel coat was painted (and he would be the one who applied the paint!)

Not much help I know and it only serves to complicate further an extremely frustrating situation.

Hi. Our supplier painted our flat roof yesterday with white heat reflective paint. The roof was still making noises in the afternoon/evening, but we will give some time to see if it makes a difference. Today has been too cool and sunless to tell.
Have you had any new attempts to fix your problem?
I think there are now 5 of us talking on diynot with this problem.
Cheers
UselessMan