Builder "forgot" DPM, how bad is this?

[Koolpc]

It is. What should I expect to happen?

Usually, you dont put kitchen units on a floating floor as it needs to be able to expand and contract.....

Was the flooring stuck down or not?

 

[ho66]

Usually, you dont put kitchen units on a floating floor as it needs to be able to expand and contract.....

Was the flooring stuck down or not?

No, it is LVT clicking floor, so the panels are connected with each other but they are not glued to the screed.

 

[Ivor Windybottom]

LVT pretty much IS a DPM, it's a sheet of plastic so will stop moisture and won't swell. So I'd say don't worry about the DPM thing.

But if the level is an issue then you may be able to remove the flooring without removing the kitchen. If done with care and some propping, all depending on the situation. BUT you will then lose the damp-blocking effect of the LVT under the cabinets, although you could possibly paint something on to fix this.

Honestly I'd say either put up with it and move on or decide whether it really is bad enough to care about.

 

[ho66]

Thank you that's good to know. Probably we'll just accept it and move on and hope that it doesn't get much worse over time.

To answer the people who pointed out that I should have stopped them before the kitchen was installed, I understand the point, but I believe it was a lot more level at that point. The floor just became worse over time during the last weeks. Some bits below the LVT (where the self-levelling should be) are now hollow. It wasn't that bad one month ago, or we wouldn't have installed the kitchen on top of it. It just seems to become worse over time, maybe that's due to the drying process?

Building regulations about floor levelness say that 3mm deviation per 1m is acceptable, we're within these limits, of course I would have hoped that the floor is much better than the "minimum" after being charged so much money, but I guess I learned the lesson that I need to include the expectations about the work quality in the contract. And do more background checks before I hire someone.

 

[bsmth48]

I can't see the lack of DPM causing problems unless the pre-existing tarry layer was also removed in those same areas, or if rising damp is already a problem. But the builders excuse of there being 'no room' to lay the DPM doesnt make a lot of sense because even the heaviest gauge plastic sheet is only fractions of a millimetre thick.

 

[ho66]

I can't see the lack of DPM causing problems unless the pre-existing tarry layer was also removed in those same areas, or if rising damp is already a problem. But the builders excuse of there being 'no room' to lay the DPM doesnt make a lot of sense because even the heaviest gauge plastic sheet is only fractions of a millimetre thick.

The plastic sheet is tiny, I think their point was that the self-levelling compound would be too thin to hold it down properly. And yes, they also removed the tarry layer.

 

[bsmth48]

That is believable. It is unfortunate that the tar was removed in that location, not sure what the point of doing that was. If the LVTs are stuck down with an adhesive, then as someone else said, they may provide an equivalent substitute and in any case the LVTs being plastic are water-insensitive. You might want to check with the manufacturer whether the self levelling compound used will hold up against a bit of damp. Some of them have to be protected IIRC.

 

[JohnD]

A thin self-level on plastic sheet is liable to crack. It can't stick to the substrate

 

[Ivor Windybottom]

PermaSEAL Liquid DPM 5L

High quality ready to use liquid applied DPM designed to be applied to floors and walls to provide a quick and reliable waterproof layer.

www.permagard.co.uk

 

[Ivor Windybottom]

The above is one example of the sort of thing that should have been used. Screed shouldn't be affected by a bit of damp though.

It's hard to judge from the other side of a keyboard. But if it's gone hollow then you definitely have an issue.

 

[ho66]

He poured floor levelling compound directly onto a plastic sheet?

I'm a wee bit baffled...

Sorry for the stupid question, but what would have been the correct way to do this? In case it changes things, it wasn't just a few mm of self-levelling compound, it was maybe 3cm or so, so still a quite solid layer.

 

[Ivor Windybottom]

If it's solid and level then it's OK. If it's not then it's not!

 

[johnny2007]

Most if not all houses I worked on, same age as yours, have a bitumen dpm below the screed.
Yours is probably the same.
You could core a sample on a hidden corner to be 100% sure.

 

[ho66]

Most if not all houses I worked on, same age as yours, have a bitumen dpm below the screed.
Yours is probably the same.
You could core a sample on a hidden corner to be 100% sure.

Thanks, interesting point. I thought I only had the bitumen dpm in the kitchen because that's the only place where I had seen it, maybe we didn't dig deep enough in other rooms. It's too late to check the other rooms now. Anyway, I'm really only worried about the kitchen because that's where I know for sure that we had this layer and removed it without installing anything new.

 

[Ivor Windybottom]

...except the thick slab of plastic flooring, which is doing basically the same job.