Floating wood floor.

[ian]

Last year laid down a floating wood floor, now i have a problem with it cupping in a couple of places.

The wood is soft pine T&G glued together and ronseal diamond hard about 4 coats, looks good apart from the cupping and springy (bounce) of the planks of wood when i stand on it in a couple of places. The subfloor is concrete with a vapour barrior and underlay combined. Their is a gap all way round the edges to allow for expansion.

I could remove the offending plank about 6 planks in from one edge and glue and re-varnish but i know this will show when i varnish it again (overlap). Could re sand the whole floor, but the diamond hard varnish is rock hard and would take many hours, already tried this on a scrap piece of wood. I was toying with the idea of hiring a hilti nail gun and fire nails through the wood and into the concrete, i have spoken to the hire company and this can be done. Quite expensive to hire, nails and cartridges are the biggest expensive. I have seen that you can now buy concrete screws, thought of screwing through the wood and into the concrete subfloor.

Has anyone got any suggestion what i should do.

Thanks.

[Steve Firth]

I secured a floating floor usign concrete screws (Screwfix "Multi-Monti") you need to be careful with the dimensions of the pilot holes, an SDS drill is essential and make sure that you use long enough screws. You need at east 45mm of screw in the concrete and I would recommend more, 50 or even 60mm if the concrete is thick enough.

FWIW it fixed my problem which was securing a floating floor so that it could be tiled with ceramic tiles.

Umm your description of the floating floor makes it sound like yours is just T&G laid over underlay, I thought the accepted way to do it was to floor with WBP then to lay the T&G on this?

[The Natural Philosopher]

Do teh same as mee, wait for winter and central heating to get it back in shape :-0)

Alternatively, put heavy weights on. With luck it will 'conform' eventually.

[ian]

Tried the heavy weight, seems to work for about two days then starts pushing up.

I agree the central heating will shrink the planks, i was amazed how much they did shrink around the edges of the wall under the skirting boards last winter. (did a proper job removed the skirting boards, that wasnt easy but better looking). I am tempted to remove the skirting to see if there is a gap around the edges i know i had left some expansion, maybe not enough.

[Stephen Hull]

[snip]

Is it not customary to paint both sides of such particularly soft timber to reduce bowing?.

If the planks are only painted on one side they will tend to warp or pull up as the coating dries.

Or was the timber already pre-treated?.

Steve.

[Stephen Hull]

I suppose you weren't to know that applying an additional coating to the underside can help stop warping as both surfaces would therefore dry more evenly and would'nt be working against each other as they dry. Warping doesn't happen so much with seasoned softwood or hardwoods.

Applying four coats of varnish on one side only will create warping especially on soft untreated timbers.

Unfortunately I've no idea what to suggest on how to remedy your problem other than what other posters have previously suggested. :)

Steve.