Q and A's on how to lay a wooden floor 4 - finishing touches
Aged & Distressed in a modern construction

Q and A's on how to lay a wooden floor 5 - problem solving

Our most popular article: "How to lay a wooden floor, keep it simple" has a total of 3 pages of further Q and A's, in our opinion becoming too laborious for everyone to have to go through. We all know every home, every situation, every interior design style and/or wishes are different so no article on its own will ever answer all questions, but we can but try.

In this (and other) article we have grouped Q and A's from the original article per, we think, related subjects.

Problem Solving
We had 90 sq m 18mm Oak T&G floating floor laid on screed this April. The wood planks are of various lengths, same width. The flooring was stored in its original packing in a heated room from December 2006 until April 2007. The carpenter stated it was fine to lay it straight out of the boxes as they had been in a heated room long enough. The carpenter used extra strong glue at the joints. We went for a floating floor because we wanted to lay underlay.

Unfortunately, gaps have appeared at the joints in some areas. In some cases these are up to 8mm wide, basically the joints have come apart. They seem worse, near the radiators. Same gaps appeared soon after the floor was laid. However, some large ones have appeared in the last few weeks since the heating has been on more constantly.

What can we do to remedy this?
Any advice will be greatly appreciated. Gugs

A: Dear Cugs
For a whole discussion and proper advice form various professional please see your own question from 31 October at the DIY-not Forum (with a popular flooring forum)
A rather good forum in our opinion.

Q: I am about to fit a solid oak floor in a room approx 4.25m x 4.25m. I had the concrete floor levelled a couple of weeks ago and I have already taken delivery of 18mm thick solid oak boards each 150mm wide. I was planning on gluing the floor straight down onto the levelled floor assuming that there was no moisture problem as the concrete had been in place for nearly 30 years with a natural floor covering which always appeared dry.

However, the levelling compound has now dried with a crazy-paving like cracking pattern all over it and I am now concerned about the suitability of the floor for direct gluing. I can't really raise the level any further with anything as thick as ply or battens so I was considering using a self-adhesive underlay. Is this kind of underlay suitable for a solid rather than engineered floor or can you recommend another solution?
Thanks, Chris.

A: Hi Chris T.
Can I ask a question first: before applying the leveling compound did you prime the concrete floor? I think the concrete floor absorbed too much moisture from the compound which resulted in the crazy-paving cracked effect.

The self-adhesive underlay is one option, but since your underfloor is now level and your floorboards are wide enough you could also opt for floating installation on 3mm Combi-underlayment.
Hope this helps

Q: Thanks for the reply.
The old floor covering was glued down with some kind of flexible adhesive and they removed as much of it as possible before covering the floor in PVA. After this was dry (a week or so), the compound went down.
Perhaps the PVA and the compound didn't get on with each other?

Anyway, the compound appears to be stuck to the floor OK, just cracked. I was considering a liquid DPM and then glue but having seen this self-adhesive underlay it seems like a much easier option and with no risk of the sub-floor breaking up when the wood moves.

Using underlay, whether self-adhesive or not I was just trying to picture what happens as the wood moves as there doesn't seem to be anything to stop the boards from cupping or bowing other than their connection to the neighbouring board. At least with glue, I imagine it offers a little encouragement to stay flat.

I must say, if I do go down the underlay route, the self-adhesive stuff sounds easier to use as long as it's as good. At least it removes the danger of getting glue on the surface and you don't need to clamp the floor as you go. It's just hard to find a first-hand review of the stuff as most advice on the web seems to stop at secret nail or glue.

Thanks again for your advice. Chris.

A: Hi Chris
The weight of the wood itself will normally 'keep it in place' without creating extra movement. All wood works, no matter how installed. If you humidity reaches a too high level even glued down boards will buckle and if the humidity gets too low the boards will shrink, that's nature for you.

Self-adhesive underlayment (the right brand - watch out for inferior 'copy-cats') is a good product, but rather expensive and the first time round tricky to use.

Glueing the board fully to a crumbling concrete/screed floor is definitely asking for trouble.
Hope this helps

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