How to stiffen loose floorboard.

[ss]

Situation:

This floorboard is at the door entry to the shower room, I have just lifted the old tiles and that one had a crack, now I know why. I will be laying new tiles soon and the problem is that `plank` (t&g) is

4 inches wide and I will be laying 9mm ply on top of it, previously it was something like 5mm ply. I have access to one end of the plank but the other end could be hell knows how many feet away under a carpet with felt on top of wooden tiles, so not keen to lift any of that.

Would the 9mm ply be enough to stiffen it or any ideas?

[tabbypurr]

Using ply to stiffen a floorboard seems odd. What is actually wrong with it? Usually they're just loose & need nailing.

NT

[ss]

I will be putting ply down on top of the floorboards for floor tiling, thats going down regardless, I am just wondering if that would cure the `springiness` in that one floorboard.

I have access to one end of the floorboard but the other end is buried under carpet/underlay and floor tiles and for all I know could be 10 feet away depending on how long the floorboard is.

[Tricky Dicky]

Screw that part of the board down that you can see and that should stop tha t part moving. If you are not aware of any movement in the portion under th e carpet then it is probably OK. If you are aware of movement then its up t o you whether you can live with it, all I would say is that loose boards te nd to chew up underfelt over time.

Richard

[Dave Plowman (News)]

If there is a lot of movement, it usually means it has been cut to allow pipes etc to be installed, and not correctly supported. Or even worse woodworm or rot in a joist.

I'd personally want to investigate why and fix it properly. And now is the time. It's no big deal to remove/replace a fitted carpet, etc, at one end.

[Tim+]

What he said.

Putting screws through floorboards without knowing what's underneath is a form of Russian roulette.

For cutting floor boards I can heartily recommend one of those oscillating blade jobbies. Had my first play with one last week and can't believe that I've managed without for so long. Absolutely brilliant for making super neat cuts.

Look for lines of nailheads so that you can identify joist positions, bearing in mind that the nailheads may be concealed in the grooves between the boards.

Tim

[tabbypurr]

in short yes, in that the ply then forms a 4" or so wide bridge, and 4" of 9mm is plenty stiff. But something in me still says stepping on the other end might disturb it.

If it's ground floor I'd want to know why its springy. Upstairs I wouldn't worry. as said an oscillating saw makes finding out very easy. I don't often use mine but when I do I'm really glad I got it.

NT

[ss]

Thanks all for the input, I have a lot of work still to do so will decide when I am ready for the floor. I have an oscillating saw.

I suspect not properly nailed down (or not at all) at other end, to date in this house I had kitchen units with no floorboards underneath and a hole in the kitchen floor that was covered with a wooden floor tile :-(

Previous owners husband died and I think she got cowboys to tart up the house before selling. The room I am working in had been converted to a shower room so the floor boards have been up at some stage, I have accessed a few areas under the floor along the way and joists etc appear ok.

[Dave Plowman (News)]

Chances are it's been cut not over a joist as that's the easiest way for cowboys.