Timber frame house; creaking & popping noises

[MrTaylor]

Apologies; I am sure I have read something about this before, but can't find it anywhere...
We moved into a timber framed bungalow three months ago, and when the weather turns, it makes some fairly loud 'shifting' noises.
These seem to come from the loft - and are possibly amplified as it is a huge and empty loft - and occasionally seem to ripple along from one end to another.
From watching the weather, it seems to have more to do with humidity than wind or temperature changes, although it may be all (or none) of them.
Of course if you go and sit in the loft it doesn't happen, and while I have checked visible joints and the floor for 'bits' (none) it is a bit alarming as it is quite loud.

Any pointers really appreciated!

 

[pinenot]

Is this anew house with builders warranty, NHBC insurance or whatever? ...pinenot

 

[dann09]

What do you mean by "timber framed"?

Does the roof have traditional rafters, or roof trusses?

How old is the house?

Have any of your neighbours reported similar sounds.

Have you ever felt any vibration when you hear the sound?

Would you say that the house is located in an exposed position?

Has any kind of renovation building work recently taken place?

 

[MrTaylor]

THANKS DAN (PINENOT) - ANSWERS UNDER:

What do you mean by "timber framed"?
WOODEN FRAME, WITH PLASTERBOARD INSIDE, RENDERED OUTER
Does the roof have traditional rafters, or roof trusses?
RAFTERS - IT WAS ORIGINALLY PLANNED WITH W TRUSSES, BUT CHANGED BEFORE 'BUILDINGS' SIGN OFF
How old is the house?
12 YEARS (SO OUT OF NHBC)
Have any of your neighbours reported similar sounds.
ALL THE HOUSES HERE ARE OF COMPLETELY DIFFERENT SPECS, BUT NO REPORTS
Have you ever felt any vibration when you hear the sound?
DIFFICULT TO SAY; THERE'S NO DUST OR OBVIOUS MISALIGNMENT, BUT IT DOES SOUND LIKE SOMETHING MOVED
Would you say that the house is located in an exposed position?
ON THE SIDE OF A VALLEY, BUT NOT PARTICULARLY EXPOSED
Has any kind of renovation building work recently taken place?NO; IN FACT WE WERE THINKING OF PUTTING A DORMER IN TO MAKE USE OF THE SPACE/quote]
Thanks!

 

[pinenot]

It's obviously movement of some structural part of the roof "when the weather turns" therefore we should be considering how in turn the - change of weather is - being applied.
First off, when you say when the weather turns do you mean when it becomes hot, stormy or what?
Second, what is the roof covering tiles, slates, shingles or what?
Finally, how are the rafters supported, you mentioned they should have been of a "W" configuration, are there now purlins running full length of roof both sides and vertical struts supporting these?? ...pinenot

 

[MrTaylor]

Thanks!
Weather - when I moved in I assumed it was the wind. Once I realised the wind wasn't always there, I figured it was a change of temperature causing timber expansion. But now the timing of the noises makes me suspect it is when the humidity changes from overcast to clear sky, or the other way round (we get weather from either SW (wet) or NE (dry), and it changes rapidly)
The roof is concrete tiles.
There are vertical struts to the rafters - one per rafter - and what I would call 'constructional timber' purlins (that is, planks, 20mm x 95mm) fixed all the way along the top of the struts (and also through the collar ties).

Does that help?

 

[pinenot]

Ah! those structural 20 x 95 will be the wind ties, whilst the original "W" support for the rafters appears to have been replaced with what's sometimes referred to as vaulted or cottage roofs, ready for conversion. I assume the collar ties are at a sufficient height to satisfy BC?
So what we have is a non purlin'ed rafter (stick built roof) with collar and stub ties supporting it and concrete tiles. Is there any sarking under the tiles or just a membrane?? The reason I ask is that that would provide racking, which I suspect your roof appears to lack, this would certainly allow uncontrolled movement i.e. induced stresses suddenly giving way and settling to a new position, not uncommon but said movement would be under better control in reaction, if more supported/stiffened. Anyone with any different views??? or any views how to achieve more control over the inevitable sudden movement of the roof style construction???? ...pinenot

 

[PeakOakFrames]

May sound like an odd question but what is on the roof? A neighbour has composite slates I'm not sure what they are made of. In the direct sun they make a loud pooping noise as the expand and contract. She says they have done this for years since the house was re-roofed.

Just a thought.

 

[MrTaylor]

Hi Pinenot - this makes more sense now (thanks). I'd guess the previous owner/builder changed spec from truss so the roof space could be used if needed, but never did anything with it.

There is sarking board (OSB) on top of the rafters and a membrane on top of that. The collar ties are about 20% down from the apex (±56 of 276cm total height, apex to joist). I inherited a copy of the BC sign-off on completion, so hopefully they checked up there!

I am thinking of doing something useful with the space, so should be an opportunity to beef it up as needed. If you have any suggestions on how, they'd be well taken.

(PeakOak - I found a few spare tiles in the garden and, testing unscientifically, think they are not composite - but I'll leave one in the sun... thanks)

 

[pinenot]

I would suggest inserting a purlin to each pitch to tie in the rafters, if space is at a premium a couple of rows of dwangs (noggins) inserted would do a similar job. This is because the roof is rafter design i.e. not trussed the rafters are independently free moving, so to speak, by tying them together via pirlins or the dwangs this will both stiffen the structure and make movement a bound procedure i.e. adjacent rafter to rafter Have a look at this site, it may help you...pinenot