Problem oak laminate floor

[pjaj]

In July I had oak laminate flooring installed throughout most of the ground floor of the 50 year old house we are renovating. The work was carried out by a firm of carpenters who are competent and have made a good job of other woodwork around the house. They have layed a lot of this flooring in new properties on my son-in-law's building site where there have been no problems.

The boards were layed over a mixture of concrete screed and old wood block according to the manufacturer's instructions. Vapour barrier underlay was used and expansion gaps were left at the edges.

The run of the boards is front to back and there is a transverse passage that runs from one end of the house to the lounge at the other end, so there must be about 100 boards side by side in the entire width. There is a large entrance hall in the middle of the house and the floor has developed a substantial hump (about 1 inch!) over 4-5 boards in the middle of it. It's like a trampoline.

I suspect that this is due to the onset of cooler, damper weather in the autumn. We are all at a loss as to exactly what has gone wrong and more importantly how to fix it with the least damage to the floor and the skirting boards. Any ideas from the flooring experts?

 

[WoodYouLike]

First things first:
when you say: oak laminated flooring, do you mean Melamine Laminated flooring (photo-copy of oak wood on 'plastic') or Wood-Engineered flooring with a solid oak toplayer?

I can't exactly make out on what kind of underfloor(s) the flooring is laid: on screed AND woodblocks?

If so, is the DPM also installed on the wood blocks?

In order to give a correct answer/solution I do need to know these little things, please

 

[pjaj]

First things first:
when you say: oak laminated flooring, do you mean Melamine Laminated flooring (photo-copy of oak wood on 'plastic') or Wood-Engineered flooring with a solid oak toplayer?

I can't exactly make out on what kind of underfloor(s) the flooring is laid: on screed AND woodblocks?

If so, is the DPM also installed on the wood blocks?

In order to give a correct answer/solution I do need to know these little things, please

It's Wood-Engineered, 3-4mm oak / chip (particle) board interior / balancer veneer.

Some of the ground floor rooms had an old wood block floor (parquet) other areas have a concrete screed. The house has been extended twice in the past.

Yes, the underlay is rubber foam backed with aluminium foil DPM.

 

[WoodYouLike]

It's normal practise to make sure your underfloor is one type of material: i.e. if you have partly concrete/screed and partly wood/ply/chipboard/floorboards you have to 'create' one type before installing other wooden flooring, otherwise you create two different types of 'climate'.

This is easiest done by laying hardboard sheets.

also, dpm should only be used ontop of concrete/screed, NOT on other underfloor materials (except perhaps vynil tiles to prevent sweating)

When installing did your fitters cut under the doorpost to create an expansion gap there? Most of the times when a floor start to come up, it's because of the boards being stuck underneath/to doorpost.

I know it looks dreadful, a lump of 1 inch high, but it normally means only to have to cut a tiny bit of the edge of the floor to correct it.

I think it's best you call your fitters back and ask them a few questions, like if they indeed cut underneath the doorpost etc.

 

[pjaj]

They definitey cut under the door frames. In many cases they had removed them, in part, as they were hanging new doors as well and replacing the skirting boards.

The instructions that came with the packs say "Old wooden floors ... always use a moisture barrier ... "

 

[WoodYouLike]

Well, something is 'blocking' the floor now it has expanded. If the expansion gap is sufficient enough to be filled with wood during normal expansion and you do have a hump other things could be wrong: we have seen a hump being created because one of the boards was nailed down (board was bowed and wouldn't go into the groove, so fitter pushed it down with a nail ) and also when adhesive had been spilled on the underlayment, sticking to the boards.
Or you have a moist problem indeed.

Who's the manufacturer/supplier of your wood recommending this? It is really bad practise using dpm on top of wooden underfloor, it creates lots of moist problems and on top of old floorboards with a ventilation area underneath it can even start your floorboards rotting.

 

[pjaj]

Well, something is 'blocking' the floor now it has expanded. If the expansion gap is sufficient enough to be filled with wood during normal expansion and you do have a hump other things could be wrong: we have seen a hump being created because one of the boards was nailed down (board was bowed and wouldn't go into the groove, so fitter pushed it down with a nail ) and also when adhesive had been spilled on the underlayment, sticking to the boards.
Or you have a moist problem indeed.

Who's the manufacturer/supplier of your wood recommending this? It is really bad practise using dpm on top of wooden underfloor, it creates lots of moist problems and on top of old floorboards with a ventilation area underneath it can even start your floorboards rotting.

Yes, I agree. With such a long run of boards, the usual expansion gaps may have been insufficient. The passage, which is about half the total run, does have a dog-leg in it, but there are no problems there.

The areas of concrete screed are a long way away from the problem area. However the old woodblock is itself stuck (mostly ) to a screed. It's not suspended.

I don't know the manufacturer, but I believe it to be French in origin. I have one of the multilingual installation leaflets in front of me and strangely there is no maker’s info on it. Also strangely, only one pack in 20 had a leaflet in it. I have one spare pack. Each pack covers just under 1sq metre. They are sealed in polyethylene sheet with plain, unmarked yellow / orange cardboard end caps.

So it looks as if we will have to remove the new skirting boards from either side of the hall and see if the floor is jammed up against the wall.