Creaky, squeaky floor on new build - Help please !!

[SproutsDad]

I have a new but badly creaking 18mm Caberfloor P5 T&G chipboard floor in a newly built kitchen diner extension, approx area is 30m2, in my 1930’s house. The boards are PVA glued on the T&G edges, it has noggins supporting every joint end, and is screwed down on 400mm centre joists at approx 300mm screw centres.

But it creaks so badly in many places that, half way through laying it I have asked the builder to stop, so that we can make a decision on how to proceed.

The structure underneath the chipboard brings three old levels and a varying void beneath of 700, 300 and 120mm depths bringing new and old joists together on the same original support brick wall. The joist spans from walls or hangers are supported by brick dwarf walls mid-way so there are no areas of more than 1.6m that are unsupported.

I have spoken with the tech helpline at Norbord who manufacture Caber P5 board. They say that chipboard itself does not creak, the noise is down to the stability and true levels of the new underfloor. My builder maintains that the floor meets current building regs and requirements and that is what you get.

I read here that people just go round putting in more screws, but that doesn’t address it at source, if the levels aren’t right then this will just set up more tension. Norbord say that screwing it down is better than nailing but that using their Joist & Joint, a soft mastic/glue to glue the board to the joist as well as gluing the side T&G joints will hold the chipboard down and remove the creaking.

There are specialist companies who will remove the chipboard (on new houses even), resolve the structural problems, glue and screw 18mm plywood T&G and use an acoustic sealant/adhesive + special fastenings. They aren’t cheap but do promise to eradicate the problem completely.

Your views please, I am not going to put expensive floor covering on a dodgy floor so would appreciate any help and direction on this.

Thanks

 

[Nige F]

Looks like it's got to come up and be re done with Joist+Joint

 

[SproutsDad]

Thanks, I agree that it needs to come up, but don't want to be the one making the decision on which solution from there, it's not my area of expertise.

Q >>> Does anyone have first-hand experience of a similar dilemma?
(and how to cure it)

In hindsight I was somewhat talked into a suspended new wood and chipboard floor. But as the makers say, chipboard doesn't creak on its own, it is the sub-floor that is almost always the cause.

I don't really accept the "they all do that mate" answer from some people.
Thanks

 

[HERTS P&D]

I had the same problem at home and found it was the joist in the wall that was moving. Repacked the joist and the noise was gone.

Andy

 

[SproutsDad]

Thanks. If only this was isolated to one specific area.
The worst is over a sleeper wall below it where old and new joists meet side by side and it actually 'cracks' when walked over it.
There are noggins between them but I suspect not meaty enough, and that there is deflection on the sleeper? I suspect it all needs tying in together with heavy screws into the brick of the sleeper.

There are other areas where it creaks under certain loads then not the next time. But I suspect that left like it is this will just get worse, not better. Especially with as the Building Control guy said, today's excessive loads in the amount we store in kitchen units etc, high load on specific bearing points which can/will make this type of board distort. he recommends doubling up with extra joists in parallel in those areas.
But he hasn't yet come up with a squeaky floor solution though?
>> Q..... any suggestions please ??

 

[John D v2.0]

I think you need to make sure there's no differential movement in the joists. Basically don't have two independent floors meeting together, in ours the old wall was demolished down to ground level and the new floor joists were tied to the old ones with noggins and the wall plates of the new overlap slightly. Also the old floor had a slate dpc that was dropping out in places so I dealt with that.
Once that's d done the floor should at least move together, on our the original square edge floor boards were replaced with good quality 18mm square ply at about 10 pound a metre square, screwed to every joist with 5x60 screws iirc. That has stopped any noise

Basically if the joists are sound and tied together with decent noggins them you should be fine, but plywood is a better product and only costs double which is worth it in the long run.

 

[SproutsDad]

Thanks John D,
You describe almost exactly the situation I have with the two floors, new and old, with joists meeting at their ends, overlapped side by side sitting on the DPC of a shared, reduced original wall. But as you say they need to now become one integral underfloor supporting a single top floor above.

There was no issue with movement of the floor when the old joists were fully encased in the wall above, that has now been removed. So I wonder if rebuilding the brick courses that were there between the joists to up to just below the top of the joist would help? That would fully contain then in brick and mortar again, then again good full size noggins should probably do the same ??

I have lifted a few of the chipboard sheets and there is definitely some unevenness when a straight edge is put on the joists and it rocks up and down by about 3 to 5mm

 

[bobsuerita]

one of the main reasons chip board creaks is down to fitting most people only glue the top of the tongue the glue needs to be put in the groove so it bonds top and bottom of tongue
also most mordern chipboard systems dont use mechanical fixings as this can cause the same issue
use either caberdeck mastik or a good d4 adhesive

 

[SproutsDad]

Thanks bobsuerita
Good point about gluing the whole joint top and bottom. The boards I have lifted so far have largely been glued on the top edge.
Norbord, makers of Cabewrfloor P5 and Caberdeck (more waterproof and with a protective foil) say to use D3 for the T&G joints, and Joist & Joint between the boards and joist, a soft flexible adhesive. They said that D4 is quite rigid/brittle and that D3 is good for the T&G side joints. They also said to fix down to the joists with Joist & Joint.

Your comment about mechanical fixings - you mean screws or nails I presume? Norbord say that if using Joist and Joint adhesive for boards to joist, then just a few nails to locate it is enough. Does this mean they rely on the board to find its own level on the J&J which is a flexible glue and acoustic sealant, instead of being pulled down by screws. From Norbord website ........

CaberFix Joint&Joist is a PU adhesive and sealant.
http://norbord.co.uk/products/floor-fixings/caberfix-joint-and-joist/

> Used to create a strong, silent and flexible bond, Joint & Joist will bond to a wide variety of materials and can also be used to provide a 100% guaranteed waterproof seal in tongue and groove joints between boards
> Provides strength, stability and flexibility when joining CaberDek floors and joists.
> Excellent resistance to temperature extremes.
> Silent bonding layer between floors and joists.​

I would like to be rid of chipboard, end of. T&G plywood is just double the price and chipboard is almost too cheap! The new Caberfloor P5 that my builder has fitted has had some exposure to water, plumber's leaks and the plasterer mixing. It has already shown signs of slight swelling; what a poor base for a £2k floor to go on top.

I know that the larger part of the chipboard problem is down to the fitting, but people also seem to expect chipboard to creak and accept it, because so much of it does. Therefore the builder seeks to pass it off as quite ok and normal.

 

[bobsuerita]

sorry ment to say d3 it will expand to a certain degree to take out slight imperfections and yes mechanical fixings screws nails
if using d3 we only put a few fixings in first row

 

[SproutsDad]

Thanks, yes D3 sounds right for the T&G joints.
You mention only putting a few nails/screws in the first rows!? Is this when using Joist & Joint Caber adhesive? What about the other boards, do you use any fixings in those?

Norbord the Caber P5 manufacturers state that with gluing the boards to the joists, the nails/ screws are just to locate the boards and are potentially removed afterwards.
>> Any ideas please??