T&G flooring problem

[craig]

I've a friend who recently put t&g pine planks down over chipboard in her dining room. The existing floor was in bad condition but was at least levelled by a contractor. Someone else laid the t&g, she didn't see the whole process so it's not too clear exactly how it's been laid.

Initially all was fine, but after a couple of weeks there are areas of a few square feet at a time that are definitely springy, as if the planks have swelled and buckled upwards leaving a void underneath. There's expansion gaps around the side, and for the most part there's slight gaps between the boards, so it doesn't look like the whole floor has swelled and expanded and caused this.

As far as I can tell, the boards have all been nailed to the chipboard using panel pins. It's unlikely they reach the joists and the chipboard won't hold them very well so they're not going to do very much. It's unclear whether the boards are glued but I suspect not. The floor has been varnished after laying- varnish went on a week or so ago.

Before hacking at something that's already gone wrong I wanted to do some research, see if anyone has comments on what may have happened and how to fix it so it don't do it again. I've been through the FAQ and not found anything, and googling back the only suggestion I've seen is that the boards have cupped, but I'm not sure how boards cupping could lift fairly large parts of the floor.

Any thoughts?

[Chris Bacon]

That's the first thing to sort out. What was the original construction, and how was it levelled? What dimensions are these "pine planks"?

Why expansion gaps around the side? Odd. If the floor's not fixed properly, the boards may well warp and bend and lift.

They may work out and cause problems.

More info... and how big is the room?

[Nick H]

I assume from the fact that you cant tell how its been laid that th boards are secret nailed ie through the tongue at an angle. If th chipboard was in poor condition then you really wont get a good fixing If you are nailing through the tongue you cant use too big a nail so it important that you fix into something solid ie floor joists. The prope job would have been to remove the old chipboard and fix the ne floorboards to the existing joists. If you can get the pine boarsd u without damaging them that would be the way to go.

Its probably easier in the long run to bite the bullet and redo the jo properly rather than mess around trying to put a bad job right

-- Nick H

[marbz]

yep! this has been covered before