Damaged laminate flooring over underfloor heating

[alan_m]

If the laminate board can be lifted slightly more the hole can be drilled diagonally starting at the edge and may hidden when fitted flush again.

Consider injecting the glue using a syringe without a needle (medical or printer ink replacement from ebay). Some syringes have fairly long plastic outlet nozzles over which the needle is attached and would allow a hole of a few mm to be pumped full of glue. Alternative, if the glue consistency allows, some of the ink refill syringe needles may be of a wider bore to allow pumping glue down a 1 or 2 mm hole.

[alan_m]

An observation The gap between the floor and the kitchen unit base seems to go to zero at the point of the dodgy board. Could the kitchen unit kick board be too tight at the point where the floor rises slightly and is levering down the laminate plank on one side of an underlying joist - and causing it to rise the other side of the joist? Perhaps remove the kick board to see if the floor naturally recovers and if it does just shave a bit from the kick board at the appropriate point.

[alan_m]

Don't consider that you have a depression but alternatively one plank is being forced up and the adjacent planks are coming up with it. The plank that is causing the problem cannot move but the adjacent planks tongue and groove has partially failed so you can depress it.

[ss]

I mentioned that in post above but rethinking it maybe that the board is slightly too long and is wedged in somewhere beyond the kickboard causing it to bow upwards.

[Tim Lamb]

Sorry. I hadn't looked at your photo. Do you know what type of boards were used for the underfloor piping? I'm using the EPS version and wouldn't risk laying laminate directly on top.

The original ground floor set up here was 25mm Jablite over concrete with 18mm glued joint chipboard flooring. There was one heavily trafficked place where the floor squeaked. I haven't stripped this out yet but I suspect the flooring joint happens to coincide with the joint in the insulation.

[Bert Coules]

Thanks for that. I've now removed the kick board in the photo, and another nearby one at 90 degrees to it (the kitchen units being in an L shape) but it's made no difference. I'm beginning to suspect that there might be a problem with the underlying floorboard(s) which if so will be a real pain. none of the laminate in this area seems to be lying properly flat and there are signs that another board is going the same way as the damaged one.

I hope it doesn't come to removing the kitchen units.

[Andy Burns]

Is there an expansion gap round the edges?

[Bert Coules]

Yes, thanks for that: sorry I failed to acknowledge it earlier. With the kickboards removed I tried to see how much (if any) gap had been left between the laminate and the walls but it's very difficult to gauge.

Could it be that the weight of the units themselves is sufficient to prevent the laminate's proper degree of expansion and contraction?

If so, maybe the answer is to remove the laminate from beneath the units.

[Bert Coules]

Thanks for that. The idea of sawing through the laminate, even with the saw set to its thickness, is rather daunting - just as the professional fitter I consulted was daunted by drilling into it - but I can see that it might be the best approach.

However, as I just wrote in a separate post, I'm beginning to have doubts about the whole kitchen area.

[Bert Coules]

It's difficult to tell since the edges in this area are covered by the kitchen units. But elsewhere the original fitters left the usual gaps and I imagine that they did the same here.

I wonder though (as I just posted separately) if the weight of the kitchen units could be sufficient to prevent the flooring expanding and contracting properly.

[Roger Hayter]

snip

You mean by friction stopping it sliding a mm or two against the kickboards? I don't think this is even remotely possible, the forces from friction are going to be much too small to cause the laminate to buckle because of the compressibility of the underlay. I could be completely wrong of course,

[Bert Coules]

Thanks for that.

[John Rumm]

If you have a similar plank, then its fairly "safe", since you can use that to set the depth of cut on the saw. That way you can make sure you go no deeper than the plank.

[John Rumm]

It could well be that the existing floor was not flat enough in the first place, and hence some boards are spanning dips in the floor substrate. Over time, the T&G edges will start to break, and that will allow a board to depress into a dip.

[Bert Coules]

I'd have preferred it if you hadn't chucked in that "fairly"! Yes, this does seem the way to do it, except that my only circular saw is a massive and unwieldy beast of a thing and not exactly a precision instrument any more, so I'm thinking of acquiring a small plunge saw purely for this job. There seem to be several reasonable-looking budget models around, such as the 18V cordless Bakita:

(Short version:

)

I realise of course that you get what you pay for, but for an immediate one-off task (and only the very occasional job (if that) in the future) it seems OK to me to go for something like that. As long as the depth gauge is reliable...

[Bert Coules]

Whoops. That's "Batavia", not Bakita.

[John Rumm]

You don't really need precision for the hacking out part of the exercise ;-)

That kind of thing looks ideal, although note that particular one can only cut 12mm, and some posher laminates a slightly more than that (although most are less to be fair).

[Bert Coules]

Well spotted, thanks.

Mine is 10mm. I'm wondering now if a thicker product might not have given rise to the problem, though it's a bit late to think about that.

[John Rumm]

When you have a void under a join in the board, you end up with the full weight of the person standing on it being supported on a third of the thickness of the board (i.e. the bottom part of the groove, or the tongue), so its quite easy to break something - especially as most are MDF backed and that is quite weak in tension across its layers)

[Bert Coules]

Which means presumably that a new board in the same position would sooner or later go the same way.

I've been wondering about installing a new floor surface on top of the laminate in the kitchen area (it's only a small corner section of an open plan bungalow) - perhaps laminate again but with the planks running at ninety degrees to the ones there now.

There are multiple snags though: the existing floor doesn't lay dead flat, there would be two exposed edges ripe for tripping over and it would be necessary to somehow fix down the new flooring so that it doesn't move. But it should certainly solve the present problem.

And another thought that's just struck me: remove the existing laminate in the kitchen and replace it with new flooring planks of the same thickness, at ninety degrees. If I could arrange suitable junction strips of some sort that might work, though I suspect that the different expansion tendencies could well be a problem.