Loud banging noises coming from new flat roof extension

[donmaico]

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.
Apparently its to do with different expansion and contraction between the wooden structure and the fibre glass as it heats and cools down.Now i dont know whether my roof is at risk but what i do know is that if i ever choose to sell this house i may have problem doing so because of the noise.I just wonder if anyone has any experience of this kind of roofing and any suggestions

 

[pinenot]

Sounds like the fiberglass cast is loose from the roof deck.
Yes this is due to differential expansion/contraction rates between the two dissimilar materials, but the roof should have been tied to the roof deck as a prevention of this.
I presume this has been noticed in the recent high winds? it is a problem in the way you fear and also a problem in stress build up.
Like breaking a nail, the first bends are difficult, but the difficulty decreases to the point of break. This analogy applies to your roof as well!

I suggest you get some filled sand bags placed around the perimeter of the roof and one or two in the center, this will apply ballast and the banging should stop, one proven you can figure a remedy...pinenot

 

[catlad]

how big is your roof. It may need cutting and an expansion joint installing.

 

[donmaico]

how big is your roof. It may need cutting and an expansion joint installing.

pretty large I guess .The extension is 4x8 mtrs and the adjoining garage about 3x6 mtrs.Sounds quite a major job .Would that not ruin the fibre glass ?

 

[donmaico]

Sounds like the fiberglass cast is loose from the roof deck.
Yes this is due to differential expansion/contraction rates between the two dissimilar materials, but the roof should have been tied to the roof deck as a prevention of this.
I presume this has been noticed in the recent high winds? it is a problem in the way you fear and also a problem in stress build up.
Like breaking a nail, the first bends are difficult, but the difficulty decreases to the point of break. This analogy applies to your roof as well!

I suggest you get some filled sand bags placed around the perimeter of the roof and one or two in the center, this will apply ballast and the banging should stop, one proven you can figure a remedy...pinenot

can this stuff be replaced with normal felt?

I am not sure I fully understand you .As far as i am aware the cast looks fairly well attached to the decking beneath it although i will check. The noises are most apparent in the evenings as the air cools and in the morning as it warms up, mostly at this time of the year as well.I dont think wind is so much of an issue I just heard a crack and the is no wind to speak of.Are you suggesting the timber will break with time?

 

[pinenot]

No not at all, I'm suggesting if my theory is right, that the separation between timber deck and fiberglass cast will get worse through time.
As I have already expressed, the weight applied test will either prove or disprove this...seemples...pinenot

 

[donmaico]

No not at all, I'm suggesting if my theory is right, that the separation between timber deck and fiberglass cast will get worse through time.
As I have already expressed, the weight applied test will either prove or disprove this...seemples...pinenot

someone did something similar by using concrete blocks round the perimeter.I would need a heck of a lot of them on my roof and then how would the rain water drain off?

 

[donmaico]

spoke to a technician from Topseal who supply the roofing material ,and he reckoned changing the current one we have which is grey in colour to a white one would help as white tends to reflect heat wheras grey is more likely to absorb it .That would of course entail considerable extra cost with no guarantee of success .He reckoned though , that the wooden platform may not have been built in a way to successfully take it whereas it would have taken a traditional felt one.

 

[pinenot]

Is the wooden platform you speak of the roof structure or am I missing something ??

 

[donmaico]

Is the wooden platform you speak of the roof structure or am I missing something ??

the roof structure ie sterling boards and joists .Whem you said platform I thought that was what you were referring to
I just had a quick look on top of the roof and cannot see any signs of the glass fibre coming adrift of the structure

 

[pinenot]

The word platform is confusing which I have not referred to, also some other things you introduce to the discussion, can be construed as confusing.

Re: looking at the glass-fiber covering the roofdeck (timber built flat roof) if you could see any signs of "coming adrift" I would be very surprised indeed, the differential movement between the two material constructs, would be micro i.e. not easily observed. However wind is a tenacious force, seeking out every weakness...and it can vibrate or whip roof tops producing very strange anomalous noises.

 

[dilly]

Hi
What were the weather conditions on the day of the lay,we're there any breaks between each layer being put down eg was the top coat applied on the same day or later.Also important on a fibreglass roof is the construction was expansion gaps built into perimeter.Also if the lay has been over catalized then the fibreglass will set with a scouring effect making it much more brittle than it should be.

 

[donmaico]

Hi
What were the weather conditions on the day of the lay,we're there any breaks between each layer being put down eg was the top coat applied on the same day or later.Also important on a fibreglass roof is the construction was expansion gaps built into perimeter.Also if the lay has been over catalized then the fibreglass will set with a scouring effect making it much more brittle than it should be.

the weather conditions were excellent in fcat it was very hot i seem to remember.On memoery i think the top layers of which thee seemd to be sevral wee all apl;ied onm the same day but I cannot be sure as itds been almost two years now.I know the whole job took well over weekend with saturday being the longest day for them.Sunday i think they just finished off.Expansion gaps I cannot see and I really dont know about your last point .The first question would be how do i find out and the second, what is the remedy?All I can see is a flat grey area with an edging all round.I have walked on it several times and nothing suggests to me there is a problem other than the noises

 

[dilly]

I know of no remedy,all you can do is try what has been suggested eg with the extra weight.topseal I presume only warranty cover is for water ingress.

 

[donmaico]

I know of no remedy,all you can do is try what has been suggested eg with the extra weight.topseal I presume only warranty cover is for water ingress.

avoiding water ingress is the main factor of course, but to someone who has little or no knowledge of building industry each loud bang sounds like the roof is giving way albeit gradually