Loud Cracking / Popping in Ceiling and Walls - Roof Truss?

Hello

We purchased a 2 story townhouse a year ago that is now nearly 2.5 years old.

We had a building inspection done before we purchased the property which came back largely clear. However, we have had a few issues with the builder that have lead me to realise he may have cut a lot of corners and used a lot of sub-contractors. I have already taken him to consumer affairs over one issue and obtained a result in our favour.

The problem I want to post about here is incredibly loud and frequent bangs, pops and cracks that come largely from the ceiling and walls. The sounds are loud enough to wake you up at night. We do have ducted heating but this is turned off at night. The problem is worse during the winter months, which is obviously due to variations in temperature. However, this does not mean we do not hear it at all during Spring and Summer.

I have mentioned this to the builder, but he has explained that this occurrence is perfectly normal (this is generally his response to everything!). I would like to know then why it has not happened in any of the other houses I have lived in throughout my life (that range from old to new, and single stories to two stories).

Through my research, I am starting to think that we may have a case of 'truss uplift'. I know it is possible for this to happen even if the appropriate building standards have been followed. However, I am concerned that the trusses in the roof were not nailed down correctly. I have been reading some material that explains that blocks should be installed on bracing walls that do not prevent the vertical settlement of trusses, that trusses should not be supported by internal walls and that trusses should not be nailed to the interior walls without clips allowing for movement.

We have already got an issue with excessively creaking floors upstairs that the builder has done cursory fixes on over the last year, only for the issue to return a few hours after he has left (this is a work in progress)! If the builder has not allowed enough expansion space for the floors to stop making loud sounds, then it would not surprise me if he has done this elsewhere.

Does anyone know who the right sort of person is for me to employ to check the above items. I am concerned that building inspectors are too unqualified and ‘general’ and that a structural engineer is not the right sort of person. Should I specifically be contacting a roofing engineer?

I have a copy of AS 1684.4 but I do not have a copy of AS 440, which I am lead to believe covers roofing trusses in more detail.

What I would like to be able to do is come up with a list of things from standards documents that the builder may have breached and give them to someone who can individually check each item.

I have spoken to the building commission ‘hotline’, who unfortunately were more unskilled customer service representatives rather than people with any genuine technical knowledge. They basically advised that the builder would have complied with all standards in order to receive a final building certificate from the council. However, I am sceptical about this. The issuing of certificates is such a routine ‘ticking the box’ type process that I am convinced it is sometimes done in a cursory way. It is also doubtful that inspectors at this point in the process always unearth every area that has been neglected or every corner that has been cut.

Anyone with any ideas, post away…

Cheers!
 
Thanks for your reply...

I believe it's actually a wood framed house (I'm going to look at all the specifications in more detail on our purchase contract though).

The sound is incredibly pronounced and comes from above – as loud as gun shots or a mini explosion – sometimes three sharp noises in a row. You can hear it from the bedroom and the living room in different places. It even happens when you step onto the bathroom tiles (in the middle of the house) for the first time every day – a loud crack coming from the ceiling that appears to be activated by your feet on the floor. You expect a certain amount of sound in a house but not this much.

The builder also said that loudly creaking floors was normal, until I found the part of the building standards and tolerances that states that if it's within 2 years it is a defect! Then he changed his tune...
 
Thanks, yes, but this is not your average expansion and contraction and we do still hear it in Spring and Summer, although not as much.

I have lived in houses with reasonable sounds of expansion and contraction before and this is not that sound...

These sounds are repeated almighty bangs and cracks! (Not little cracks, creaks or groans)
 
Through my research, I am starting to think that we may have a case of 'truss uplift'. I don't think this is the case - uplift occurs under very strong wind loads. Even in cyclonic areas the roof sheeting, and battens will fail before the truss tie down does.
I know it is possible for this to happen even if the appropriate building standards have been followed. However, I am concerned that the trusses in the roof were not nailed down correctly. Trusses aren't nailed, they're fixed with framing anchors or strapping - I don't think the movement is here. I have been reading some material that explains that blocks should be installed on bracing walls that do not prevent the vertical settlement of trusses, that trusses should not be supported by internal walls and that trusses should not be nailed to the interior walls without clips allowing for movement. You're on the right track, 'Blocking' is used to tie in a non-load bearing bracing wall to the truss bottom chord, while ensuring there is a vertical movement gap. It's possible the builder omitted the movement gap and the non-load bearing walls are supporting the truss. But I'd don't think this is the case.. You'd most likely hear the bottom chord of the truss snapping once, rather than consistent popping which you hear so regularly.

Can you get into the roof cavity and have a look for yourself? A) If there is any splitting in the roof trusses and B) the connection details comply with AS1684?


We have already got an issue with excessively creaking floors upstairs that the builder has done cursory fixes on over the last year, only for the issue to return a few hours after he has left (this is a work in progress)! If the builder has not allowed enough expansion space for the floors to stop making loud sounds, then it would not surprise me if he has done this elsewhere. That's pretty poor form of the builder, creaks should not be "normal" in a new house. He should fix asap.

Does anyone know who the right sort of person is for me to employ to check the above items. I am concerned that building inspectors are too unqualified and ‘general’ and that a structural engineer is not the right sort of person. Should I specifically be contacting a roofing engineer? A structural engineer which would give a detailed report at a price. Or an experienced builder for a lot cheaper..

I have a copy of AS 1684.4 but I do not have a copy of AS 440, which I am lead to believe covers roofing trusses in more detail.

What I would like to be able to do is come up with a list of things from standards documents that the builder may have breached and give them to someone who can individually check each item.

I have spoken to the building commission ‘hotline’, who unfortunately were more unskilled customer service representatives rather than people with any genuine technical knowledge. They basically advised that the builder would have complied with all standards in order to receive a final building certificate from the council. However, I am sceptical about this. The issuing of certificates is such a routine ‘ticking the box’ type process that I am convinced it is sometimes done in a cursory way. It is also doubtful that inspectors at this point in the process always unearth every area that has been neglected or every corner that has been cut.

Anyone with any ideas, post away…

Cheers!
In my opinion it still seems like seasonal movement. What could have exacerbated it is the timber framing not being adequately seasoned prior to installing. The timber could be drying out more than normal, followed by the normal shrinking in low humidity conditions and swelling again in high humidity conditions. Not installing seasoned timber is ultimately the builders fault. It could be worth chasing up the documentation from the builder of the timber specs stating the timber is adequately seasoned?

I'm not too sure of the process in claiming recourse through a builder other than contacting the building commission and saying the townhouse is still faulty.
 
Thank you vbplease!

Your reply was helpful in thinking that I am not barking up the wrong tree with all my ideas.

Ordinarily, I wouldn't initially be so suspicious of building work, but having met the guy, I am now! I won't go into the whole thing but he has been a little painful to deal with.

He has agreed to fix our floor, but he keep comes coming around and does half a job, only for the problem to return. The floor is actually worse since the last time he was here! If he just came once and did the whole thing properly, we wouldn't keep calling him back and he would be rid of us!

In relation to the trusses, I have read a number of reputable publications, mainly form America that state that truss uplift is becoming a huge problem with new builds, particularly in cold weather which is also exacerbated by the fact that the prefabricated materials used now can often be of inferior quality. The timber is also often grown rapidly and artificially, making it more susceptible to expansion etc. There are many people, both the general public, builders and engineers who have said that the problem is a genuine one. The uplift occurs because the lower part of the frame is under thick insulation and therefore is dryer and contracts, while the upper part is more exposed to moisture and cold and swells, causing the lower part to bow up. If my builder had nailed my internal walls down rather than using the brackets or clips he is supposed to in order to allow movement, then a bowing effect could cause the nails to pull up, and hence the sound. I am really treating this as a distinct possibility.

You may also have something in saying that the wood may not have been seasoned properly. I will look into all the codes further and see what I can find out. Might try and bribe a friend who has more knowledge about these things than I do to get up in the roof and have a look!
 
i swear there was a thread with this exact problem a year or so ago, maybe try a detailed search of this forum to find it.

cheers
 
Chippie47

Hi we live in a 4y.o home in geelong with same problems. Not too much noise bit heaps of square edge plaster cracks. Pit straightedge against ceiling and its lifting. Hav suggested truss uplift but all experts insist its external walls lifting and trusses lifting with it. Funny though, its weatherboard and no external signs of wall lift.
Bottom chords are crowning as cracks are only in centre of property where centre of truss is.
Good way to determine if its the walls lifting ti to laser the floor from centre to end walls. Our floors are level, indicating no walls lifting and no gaps between floor and wall.
Hv u had any ideas on how to establish roof or timber moisture over a 12 mth period? This may establish if its uplift or not.
Also our place built in the drought where timber is at its dryest so i think my instance is uplift.

Just sharing a similar story any ideas please let me know
 
Just a thought was the construction halted for a long period of rain while the frame was up un covered?

I think I would call in a structural engineer and try to replicate the sounds. It certainly shouldn't be normal to have loud cracks in any house. Creaks and groans are movement and expansion but anything more is something moving. You can sometimes have metal roofs crack when they expand if they are not fixed correctly. As I say call in a structural guy.
 
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