Squeaky/creaky floor in new extension

melb

The floor in our single storey extension is creaking in various places towards the centre (not round the perimeter it seems).

We are going to be laying under-floor heating, underlay and then engineered wood on top.

The builder says he has glued the tongue and groove chipboard/floorboard, whatever it is, and then put screws in and this is as much as he can do.

He is trying to reassure us that once all the other layers go on top, we will not be aware of the creaking.

Should we put our trust in him? Would be grateful for any replies. We have now stupidly allowed the underfloor heating to be laid but it is the foil type, has not been connected up yet and so presumably could be rolled back if necessary.

This extension has no joists connecting up with existing ones in the house as it has been built onto the back of the house, if this makes any difference.

Ruski

Found after a quick google - re the last sentence:

The relevant NHBC standards regarding chipboard flooring are:
"6.4 - S14
Flooring shall only be fixed when the dwelling is substantially weathertight
6.4 - S15
The length of nails should be 2½ times the thickness of the decking.
The ends of adjacent boards should be square. Joints should be staggered and supported on noggings or joists.
Temporary wedges and packings at the perimeter should be removed after the floor decking is complete.
6.4 - S18
Chipboard flooring shall be of the type and thickness specified
Only moisture-resistant, Type P5 chipboard to BS EN 312 should be used for flooring. Joist centres should not be greater than 450mm for board thickness of 18/20mm and 600mm for boards 22mm thick.
6.4 - S19
Chipboard flooring shall be securely fixed
Chipboard should be supported and fixed in accordance with manufacturers' instructions, using either
flat-headed ring shank nails minimum 3mm diameter and of length 2½ times the thickness of the chipboard, or screws.
Edges at room perimeters should be supported on joists or noggings.
Fixing centres to joists should be:
200mm - 300mm centres around the board perimeter
400mm - 500mm centres on intermediate supports.
Expansion gaps should be not less than 10mm wide where boards abut a rigid upstand. For larger areas of boarded floor a wider gap may be needed at upstands and intermediate expansion gaps equal to 2mm per linear metre of floor provided.

Tongued and grooved chipboard:
Boards should be laid with long edges at right angles to joists
Short edges should be supported on joists or noggings.
Projecting ends of boards should be cut back to form a butt joint on a joist.
To reduce squeaking, tongued and grooved joints between boards should be glued and the boards should be glued to the joists. A suitable polyvinyl acetate (PVAC) adhesive should be used."

Worked for me on a recent renovation.

HTH

Russ

Furts

If the floor squeaks and creaks now then it will still do so when the floor covering is on. Now for a "but". The proposed ufh is likely to make matters worse because heat will be affecting the floor. Here think of the joists getting dried further, a reduced moisture level, and uneven distortion. But also the chipboard will tend to dry and try to pop the fixing nails upwards.

Ruski is right about the glueing but this raises delicate questions. It has been a requirement to use glue for at least 30 years. You do not say where the glue has been used. Basically it is a three pronged attack - tongues, grooves and to the joists. Many builders seem to ignore this. The delicate issue is how informed, how careful and how competent was your builder?

But there is a certainty here. If your chipboard was not glued to the joists I would (almost) guarantee you will get additional problems once the ufh is working.

The other issue is the joists. As the areas of squeaking are in the middle of the floor this suggests excessive joist deflection This in turn means undersized, defective or poor quality floor joists may have been used. Floors are an absolutely vital piece of building so ask some searching questions here. What did you witness? What did the Building Inspector check up on?

melb

thanks for replies. We do have photos of the joists (don't ask me to put them on here as I have no idea how to do it) and they look fairly meaty as far as we can tell as laymen.

Would the building of the joists be one of the stages at which the Building Controls person would want to come and check? Don't really know how they work - they just seemed to appear at random stages.

We will be having underfloor heating as this will work best for us - I am sure we won't be the first to use it in a new extension underneath engineered wood flooring so it must work ok surely?

Furts

Floor joists would be a typical inspection but there are a couple of buts here. It depends what has been agreed in advance, or what the Stage Inspections have been set. It can also depend on risk analysis which unfortunately can be a cover for staff shortages.


People do install ufh on bedrooms. Whether this is wise, whether this is effective, does it follow the principles of ufh and such like would all open up new debate. An anecdotal answer would be this. If you go into the show homes of typical family homes being built the big builders they are unlikely to have ufh.


If your ufh has been designed in from the outset and you have the manufacturer details and come back then fine. If it is an add on, done when everything has been completed then do some thinking here.

melb

I would think unless you're talking premium spec newbuilds then ufh wouldn't be used as it's more expensive than radiators to install maybe?

We didn't have a designer as such, but the builder knew from the outset that ufh was to be used. Anyway he feels confident enough to guarantee it will not creak when all the various levels of underlay etc and wood have been laid so once we get that in writing we will take his word for it

AndyMc.....

melb wrote: »

I would think unless you're talking premium spec newbuilds then ufh wouldn't be used as it's more expensive than radiators to install maybe?

We didn't have a designer as such, but the builder knew from the outset that ufh was to be used. Anyway he feels confident enough to guarantee it will not creak when all the various levels of underlay etc and wood have been laid so once we get that in writing we will take his word for it

Good luck with that.

melb

yes my thoughts exactly!

Furts

You are engaging in a risky scenario. You are saying that a problem exists but you are burying your head in the sand over it. This might work - nobody knows but the chances are not favourable.

If you were treating your extension with the mindest of somebody in the construction industry then problems get picked up as work progresses and they get dealt with then. Why? Because it is cheaper, quicker, and allows everybody to move on as quick as possible to the end goal - a satisfactory (hopefully) building completion.

Rectifying your problem may be possible by removing the ceilings below the joists. However it might mean re - fixing the chipboard. When your ufh and laminate is down this is far less likely to occur. You have to be realistic here - the builder is running a business, defects cost profits, and the longer you leave matters the less likely they are to get resolved.

melb

thank you. He has said it must be the Noggins as it is only along the centre of the floor. If the creaking is still audible after the wood flooring has been fitted he can tighten these from underneath as we have a storeroom and cellar underneath for access.

The extensions looks great and he has not skimped on any materials so I am happy to go ahead with this option - well not happy but prepared to go along with it.

Furts

melb wrote: »

thank you. He has said it must be the Noggins as it is only along the centre of the floor. If the creaking is still audible after the wood flooring has been fitted he can tighten these from underneath as we have a storeroom and cellar underneath for access.

The extensions looks great and he has not skimped on any materials so I am happy to go ahead with this option - well not happy but prepared to go along with it.

Do you have to board out the underside of the joists for fire protection? If it were a garage area then yes, but what is being stored in there - petrol engined lawn mower for example?