Uneven Subfloor and Screw Pops in New House

almostover · 24-12-2021 12:02pm #1

Hi,

This may be some paranoia on my behalf but I have some worried about the construction in our newly purchased house.

Firstly the context. The house was built in 2009 in a ghost estate. It is one of 14. Block wall with 100mm cavity. Has been lined with insulated plasterboard to get up to A3 BER. We've moved in with a month now and it's very warm. No issues that way. House was complete externally with windows but unfinished internally when we viewed late last year. We had a fully engineering survey done before buying and no structural issues were identified. Some minor snags were highlited at that time and passed to the builder for remedy.

What's troubling me since moving in is the ceiling joists / subfloor. There is an uneven gap under the doors of 2 adjacent rooms upstairs. Only noticed them after I laid down the laminate flooring. I had some squeaks in the subfloor snagged before handover that that was addressed. I've attached an image of the worst of the 2 gaps. In general the 2nd fix carpentry was of poor quality, which we also snagged and had most of it addressed. I'm worried however about twisted / sagging ceiling joists. We have a warranty from the builders for 6 months on minor defects and 18 months on major defects and want to avail of it if necessary.

There was a bit of a rush putting down the laminate flooring and now that its down I'm not fully happy. The uneven gaps under the d

oor is one thing and also the subfloor is a little creaky in one or two places. We used very high quality underlay so I know that is not the issue. We're also getting a lot of screws popping in the ceiling downstairs under the area where I suspect the floor joists to not be level. Some images of this are attached too. I brought the screw pops to the builders attention and they fobbed it off because at the time I was drying clothes in front of a rad in the room with the screw pops. More pops are appearing though and I know some are normal but it seems excessive.

Can someone more knowledgeable than I take a look please and offer some advice? Even just to help with my paranoia. My partner thinks I'm being a bit pedantic but I'm anxious that if an issue exists that we get it addressed while we have warranty cover. I'm thinking of getting out engineer out after xmas but want to make sure I'm not wasting my time and that it's a carpenter I should be getting to relay the laminate flooring!

10-10-20 · 24-12-2021 2:53pm

Without knowing the proximity of the nail pops to the crack and the proposed 'sagging', it would be hard to define a defect such as this from here. :)

How long were the joists installed and were they finished with T&G or ply flooring back in 2009 or what timelines were involved in terms of completeness? Was there any indication of water intrusion over the period?

C. Eastwood · 24-12-2021 3:17pm

https://www.boards.ie/discussion/2058224202/uneven-subfloor-and-screw-pops-in-new-house

almostover. I cannot figure out Photo 113613. What is it meant to be showing.

Why are you getting the laminate flooring relayed?

I will explain the cause and remedy of the plaster popping off over the slab nails first.

You stated -“ I brought the screw pops to the builders attention and they fobbed it off because at the time I was drying clothes in front of a rad in the room with the screw pops.”

You naughty boy. Ha ha. This is so funny ha ha ha. Many Builders have no qualifications whatsoever and spew out this fairytale rubbish again and again. The builder blames you for the popping of the plaster over slab nails heads because you were drying clothes in front of a rad. And I thought I had heard every fairytale told by builders. Feck - Fr Jack springs to mind.

If you lit a camp fire in the middle of the floor for a few hours - it would not cause the popping of the plaster over the nail heads.

Most Builders and Craftspersons do not know and will never know the cause of this phenomenon.

Painters & Decorators carry our repairs by filling over the nail heads and repainting over the filling, and when the popping occurs again they come up with brilliant Fairytales, and they could be doing this for 40 years or more.

The cause of the plaster popping off over the heads of slab nails occurs because the timber bearer behind the slab, which the slab is fixed on to is not straight, and therefore the back of the plasterboard slab is not fixed up tight against the timber bearer. This just happens because it would not be feasible for slabbers to check this at every nail. So it happens, it is easy to prevent it from reoccurring. Any movement in the floor or ceiling above, or a person leaning against a slabbed partition will cause the popping.

Remove the plopped plaster over the nail head.
To confirm to yourself what the problem is - put your thumb on the plaster surface at one side of the nail head and approx 20 mm away and put your finger at the other side.
Push the slab in towards the timber stud/ joist behind the slab.
Observe that the slab moves in - but the nail head does not.
What you need to do is fix the slab in tight against the timber bearer.
Thy method I use to resolve this- is to push the slab tight against the timber bearer with one hand, and with a cordless screwdriver- drive in 2 screws in through the slab in to the timber bearer. One at each side of the slab nail and approx 25 mm away from the nail. Fix the slab permanently tight against the timber bearer.
If you do not push the slab tight against the timber, the screw heads will not push it in either.
Take care to not allow the screws to go in through the paper of the plasterboard slab.
You have now permanently secured the slab tight against the timber support.
The head of the slab nail will be projecting out a little from the new position of the surface of the slab.
Using a screwdriver (or punch), and hammer, place the tip of the screwdriver on the head of the slab nail and using the hammer - tap in the nail flush with the paper of the slab.
Do not tap in the nail with the hammer because you may damage /crack the solid gypsum core of the slab.
Fill the popped area of plaster with interior Polyfilla, and paint over. The plaster will never pop again at this area.
Warning:- Never try and explain this to a Builder. 😂😂😷😷

When clothes are dried near or on a Radiator- the moisture in the clothes-vanish in to this air - and may appear again on a cold surface in the form of Surface Condensation or in the form of Condensation Mould Growth. This problem might not occur in your A3 BER rated house, because you have Insulation and Ventilation.

Steam - (Insulation + Ventilation) = Condensation.

10-10-20 · 24-12-2021 3:22pm

And if you're going to do the method provide above, use plasterboard/drywall screws and not general or wood screws otherwise you'll have a rust-stain in the years to come.

https://www.mcmahons.ie/rawlplug-drywall-screw-3-5x38mm-coarse-1000

almostover · 24-12-2021 3:54pm

https://www.boards.ie/discussion/comment/118370092#Comment_118370092

The joists were in place since 2009, subfloor was put in earlier this year. Our engineer's report recommended that the builders re-treat the ends of the joists with preservative but that was the only comment made about them in the structural survey. Whether that re-treating was done or not is anyone's guess because the next time we saw the place the subfloor and ceiling were on! OSB 3 subfloor was put onto the joists. That was all detailed in the building specification provided in our contracts and the engineer reviewed the specification and didn't have any issues with it.

The joists could have been somewhat damp and the use of heating now may have dried them out causing some shrinkage? Would that be the issue? There was no indication of water intrusion noted by the engineer when he did the survey but I'd imagine that timber would take on some moisture over 10 years in an unheated property.

almostover · 24-12-2021 4:03pm

https://www.boards.ie/discussion/comment/118370182#Comment_118370182

Really good advice there, thank you. That photo is showing the level in the doorway where the uneven gap is under the door. All my photos rotated 90degrees for some reason. I'm not getting any laminate flooring relayed, not yet anyway. My issue is that the subfloor is not level in places upstairs and that has lead to uneven gaps under some of the doors.

I'll have to get good at the popping repairs, plenty of them appearing now! The slabbers used screws so guessing instead of punching the nails in I should tighten the existing screws in by hand and add the extra screw to secure it?

Ya the clothes drying thing was silly, the room I was doing it in has MEV so any moisture in the air is being pumped out. Shouldn't be drying clothes indoors anyway but that isn't the cause of the issue.

C. Eastwood · 24-12-2021 4:27pm

https://www.boards.ie/discussion/comment/118370315#Comment_118370315

Thanks for the nice comments

C. Eastwood · 24-12-2021 6:54pm

https://www.boards.ie/discussion/2058224202/uneven-subfloor-and-screw-pops-in-new-house

Almostover. Looking at photo 114059 The crack is in the short span of the ceiling and it is in-line with the face of the partition where there is a clock hanging.

I do not know what is above this. Is it a floor or an attic.

There are a number of reasons for these cracks occurring. It is always difficult to determine the cause of these defects without carrying out a full Survey of the construction around the defect. Therefore I will have to guess.

The slabs on the ceiling may have been kept in-line with the clock partition. So the crack is possibly between the joint of 2 slab edges.
It is also possible that the plasterer may have omitted the Scrim over the joint before plastering the ceiling.
The joists may be running perpendicular to the crack.
If the joists are in-line with the crack, there may not be enough bridging to prevent the joists above the crack from twisting or some movement.
Sometimes cracking occurs because of twisting in timber joists because of shrinkage in timber. However, you stated the house was constructed in 2009 and it was weathered since then, and you moved in about 1 month ago.
When the house was weathered for 10 years, hopefully with some ventilation it would have kiln dried the internal timbers to approx 18 % Moisture Content (MC)
When there is artificial heat applied in the house, all the timber in the house will eventually reach the Equilibrium Moisture Content which is dictated by the Relative Humidity in the house. Therefore Attic timbers will attain approx 16 % MC, and the timbers within the heated / ventilated house will attain an MC of approx 12%.
The reduction in the MC of the structural timbers will cause shrinkage but will also cause twisting in the timbers and may result in cracking of the rigid plaster.
Rake out the crack with a screwdriver, fill with a flexible interior filler in accordance with the manufactures instructions and repaint.
If the crack keeps on occurring- it may be a structural issue.
Let me know if there is further information.

C. Eastwood · 24-12-2021 7:20pm

https://www.boards.ie/discussion/comment/118370282#Comment_118370282

almostover. If the screws in the slabs, which I recommend, had any possibility of corroding, I would have specified Stainless Steel screws to you. Your house is an A3 BER rated house and for corrosion to occur on metal there must be air and moisture. There is no possibility of moisture occurring on the inner surface of the internal plaster of your home.

almostover · 24-12-2021 8:00pm

https://www.boards.ie/discussion/comment/118370720#Comment_118370720

This is great information, thank you. That crack is in the ceiling of the kitchen which is downstairs. There is chance that it is on the seam between 2 slabs of plasterboard. The joists would be running perpendicular to the crack. I'm guessing that much of the issues I'm describing here are being caused by the ceiling joists drying out now that the heating is being used. There is air to water heating installed and we have it set to approx 20C both up and downstairs via the thermostats.

We have some other smaller hairline cracks elsewhere in the downstairs ceiling in particular. I'm satisfied that the structure of the house is OK as the engineering survey was done when the inside of the house was bare block and there was zero evidence of issues. It seems the drying out of the timber work after 12 years is causing some cosmetic issues.

Appreciate all your advice. I have been obsessing about this the last week or so. But if these things are easily repairable that would calm me down. I'm thinking of getting the engineer back in January for a quick survey because if anything is amiss now the builder's are contractually obliged to repair.

almostover · 24-12-2021 8:01pm

https://www.boards.ie/discussion/comment/118370784#Comment_118370784

Perfect, the screws that have been used are plasterboard screws and there is no evidence of any rust so all is good in that regard.

C. Eastwood · 24-12-2021 8:17pm

https://www.boards.ie/discussion/comment/118370892#Comment_118370892

Great. Have your engineer check out that the floor joists have the correct structural stamp and that they are correctly sizes in relation to the span of the joists.

I will reply re your doors and floors soon.

Uneven Subfloor and Screw Pops in New House

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