Banging/knocking from flat roof

maurice28

About 18 months ago we had a flat roof extension built on the back of our house and all has been good. I've noticed recently though that there is intermittent banging/cracking/knocking noises from the roof. It isn't constant, I just notice it now and again when I'm sat in there, mostly during the day.

I've done some reading and know it can happen due to the materials contracting and expanding - I must say I've only started noticing it since the weather has got (slightly!) warmer. There's no obvious bulges, cracks, rips or anything else either on the roof itself or the ceiling of the extension.

I just wondered if anyone else had experience of their flat roof making these kind of noises, and whether at this point it's worth getting someone in to check, and what they would even check for?

DRP

Is it a fibreglass roof?
is it a warm roof construction (Insulation on top of the joists)?

You might have seen this thread on a different forum:

https://www.diynot.com/diy/threads/noise-from-grp-flat-roof.374200/

I have a similar thing but it’s worse than occasional and sounds like Rudolph and Santa have landed on the roof.

I’ve had suggestions from builders that not enough fixings were used through the roof into the joists allowing thermal expansion and contraction to cause differential movements between the ply deck and the joists and/or the grp fibreglass. Basically a badly constructed roof. 

I don’t see anyone offering an easy solution . Possibly strip the roof and replace with rubber Epdm or felt which is more tolerant of movement.


I would also appreciate any comments from folk who might have fixed this!

DRP

By the way, where in the country are you? We might have the same builder? 🙃

Slinky

Are you sure it's the roof and not the guttering? Black guttering clicks and clunks a bit with thermal expansion and contraction.

maurice28

Thanks both - it's a warm roof construction with EPDM. 

It certainly sounds like it's the roof itself, the sounds seem to be coming from directly above or sections of the roof without guttering, so that's how it seems anyway.

Anyway, it isn't a massive issue, I just wondered if many people had similar and if noises are per se anything to worry about.

Slinky

We too have a flat roof with EDPM and no, we don't get any noises from it.

twopenny

I've moved into a bungalow that makes scarey noises from the roof.
I've got used to the cracking of the plastic guttering but every now and again there's a crack from the roof that makes you think something is wrong.
It's still making me jump after 5yrs.

It's a small estate and the rafters are small but apparently all my neighbours have the same thing.

So far in twenty years we've all got sound roofs on and no one has had any repairs.

Tben there's the squirrels and pigeons, even seagulls landing that sounds like someone is on the roof.
It's pitched, not flat.

Chloe_G

We've got a total flat roof and sometimes the magpies, crows, pigeons and squirrels hold a party up there!

jonnydeppiwish!

Welcome to flat roofs - it’ll be the soffits and facials when the sun comes out and warms them up. Totally normal.

youth_leader

I thought it was just me - I've been out the garden squinting up at my roof many times trying to work out where the 'thumping' noise was coming from on my resin flat roof.  I'll just live with it, thanks for bringing it up.

Swasterix

Same here. Flat roof with GRP which makes the odd bang and crack. I just put it down to thermal expansion now it’s getting a bit warmer. It’s no more noticeable than the rest of the house which creaks and groans in the night.

 Chloe_G said:

We've got a total flat roof and sometimes the magpies, crows, pigeons and squirrels hold a party up there!

I can level with this too. This chap paid me a visit the other day and was eying up my spaghetti bolognaise through the roof window…