new slate roof goes "snap, crackle pop" in the cold

[RobertL]

Background: In the summer we had the back bedroom roof of our victorian terraced house reroofed. It has the original rafters but eveything else is new. It has slate/impermeablemebrane/air gap/ celotex/thinsulex/plasterboard .

The problem: On clear nights, when the temperature drops fast, the roof starts to "crackle and pop". The sound come from all over the ceiling and is quite loud. It's as if someone is dropping small stones onto the roof from a great height. If you go out in the back garden you can hear it clearly and it seems to be coming from the slates. It does this for about 20 minutes and then it stops; last night it began at about 11 pm (in Cambridge).

Another thing: when I went in the garden to listen, I noticed that I could hear a similar noise from another house that also had recently had the roof redone (by a different contractor).

Is this a well-known problem? How do I cure it? We couldn't sleep in that room. In fact, it's so loud it wakes us up in the front bedroom!

Robert

[dom]

MY whole roof replaced on a chapel conversion (slates, battens, breather) on original joists, 18 months ago - yes, mine did that too for the first 6 months, less so now Nighttime after a very hot sunny day would do it too.

AFAICT it's just settling, and does diminish after a few months. In fact with mine it was like a little wave of tinkling sounds running back and forth across the roof.

If there was visible distortion of the roof, or loud cracks like an imminent failure of a timber, I'd worry.

Otherwise, best not to focus on it - it will only seem louder and more intrusive because you do.

I'm also getting creaks from the 6 velux windows I put in whilst having the roof done, or rather from the paneling around them. This seems to be because of differential thermal movement between the timber inside the insulation, and the joists outside.

These aren't going away, so I think I'm going to have to change the way I've paneled in between the joists/velux on the outside and the studwork inside, so one side has a sliding joint.

[RobertL]

I wonder if it's ice freezing the slates together but then cracking as further cold makes everything contract and move a little. I can't think that just shrinkage would make such pronounced "crack" sounds. Nothing structural seems to be moving. At first I was worried it was frost heave moving the walls about but it doesn't seem to be.

The roof pitch is very shallow (16 degrees) and this might encourage water to get held between the slates I suppose.

I do hope it stops after a while! The room is unusable for sleeping.

Robert

[Kipper at sea]

Are you sure there slates as slates dont go down to 18 degs. The recommended lowest pitch for slates is 22 1/2 degs. 24" x 12" with 4" head lap. On the other hand some single lap interlocking slates and tiles do go down to 17 1/2 degs.

[RobertL]

yes, i am sure they are plain slates. It was an existing roof (victorian back of house) with a very shallow pitch and BC allowed it with a completely impermeable membrane under the slates. there is a

50mm air gap under this membrane but I guess there can be wetness between it and the slates which could freeze.

Robert

[eastmans.cottage]

Hi Robert,

We extended our house over a year ago, installing a new section of slate ro of. We are experiencing the same "snap, crackle, pop" sound you described whenever the temperature drops at night. We now sleep in the old part of t he house whenever it is cold. Did your roof settle down eventually or are we going to have to do something to fix the problem?

Douglas

[MM]

I should have thought it's all part of that olde worlde feel?

[Brian Gaff]

I dunno but after getting new plastic guttering, there is snap crackle pop from that on hot sunny days and as it coold s in the evening.

I've never heard of slate doing it though. Brian

[Tim Watts]

That can be cured with a little silicone grease on the joints (plumbers grease).

[Andrew Gabriel]

You can get plastic guttering with a white inside, which significantly reduces this. I've no idea what the make is, but it's what my brother's roofer used. Also came with protective film on the outside which you peel off after fitting, to preserve the high gloss finish.

[Brian Gaff]

I'm sure it can, but that means getting a bloke or blokess in nowadays. Brian

[RobertL]

roof. We are experiencing the same "snap, crackle, pop" sound you describe d whenever the temperature drops at night. We now sleep in the old part of the house whenever it is cold. Did your roof settle down eventually or ar e we going to have to do something to fix the problem?

Yes it did settle and now makes no noise at all you will be relieved to hea r.

It took one hot summer to dry out the timbers in there. We now sleep in th at room.

I think it got very wet when they built it - they took many weeks to do it and it did rain directly onto the battens several times. I think that what happens is that the timbers freeze to each other and then the further cont raction in the cold breaks the ice going "snap crackle pop". Now the water has all evaporated there is nothing to freeze.

Robert

[Andrew May]

My first thought was that this would lead to differential expansion on the inside and outside and hence warping. I assume this is not the case.

[jfflkjflkjflkdfj]

I expect it's the fresh slates rubbing against each other as they contract in the cold. There must be thousands of little points of contact between them all. These will slowly wear down over time as slate is relatively soft, until it goes quiet.

[meow2222]

It should reduce the temp differential.

NT

[schmidtmajbritt]

roof. We are experiencing the same "snap, crackle, pop" sound you describ ed whenever the temperature drops at night. We now sleep in the old part o f the house whenever it is cold. Did your roof settle down eventually or a re we going to have to do something to fix the problem?

Hi Douglas,

We have a new house with a slate roof and we have observed exactly the same noise from the roof as you describe when temperature drops below 0 deg. C and the humidity is high. The noise last for 20-30 minutes. I know it is lo ng time ago, since you describe your problem, however, I just wondered whet her you ever found an explanation to your problem and if it stille exists ? It has not been possible to finde anyone that could give me an explanation .

Kind Regards, Majbritt, Denmark

[Brian Gaff]

Houses have always made noises from my point of view its merely the expansion and contraction of dis similar materials. Gutters are very prone to it if plastic and when they start to warm up in the sun, likewise recently installed roofs do it as there is no build up of detritus that softens the slight slidings that otherwise occur in jerks. When we had to have a few wooden items renewed due to rot near the eaves they clicked and groaned for about a year then seemed to settle down.

Brian

[tabbypurr]

te roof. We are experiencing the same "snap, crackle, pop" sound you descr ibed whenever the temperature drops at night. We now sleep in the old part of the house whenever it is cold. Did your roof settle down eventually or are we going to have to do something to fix the problem?

me noise from the roof as you describe when temperature drops below 0 deg. C and the humidity is high. The noise last for 20-30 minutes. I know it is long time ago, since you describe your problem, however, I just wondered wh ether you ever found an explanation to your problem and if it stille exists ? It has not been possible to finde anyone that could give me an explanati on.

The thread you're replying to explained it. It's here:

NT

[Andrew]

My neighbours UPVC gutter and barge boards make a racket when the sun comes out suddenly, and they expand. Sort of crackling noise.

One of my joists makes a sudden 'boing' in the winter when the house has cooled down and the heating makes it expand again.

[Dave W]

Could it be something to do with the fact that modern slates are fakes, not slate at all but a grey composite?