Bathroom floorboard removal

danrv

Hi 
Just replacing a few 18mm floorboards in my bathroom and was wondering the best way to lift them.
One small one was quite easy as it broke but the larger one here under the loo outlet is quite solid but water damaged. Also noticed it’s not tongue & groove.

I’m currently working around the cast iron bath and hope to retain most of the floor and get it level. There is one board (bottom pic) that is level under the bath but is bowed up at the corners n the middle f the floor.
It’s all DIY and can get the bath out but don’t want to be too long without one.
Any help appreciated.

FreeBear

If there are no screws or nails holding it down, it should just slide out. But if you want to avoid lifting it, take that small piece out (looks like you've already cut it). Clean out any crud sitting on top of the joist under the edge of the board, and then pull it down with some screws. Drill a hole through the chipboard first and clean out the sawdust underneath, and it should go level.

Also check that the debris under the floor is well below the level of the joists. Ground floor bathroom ? There is a risk that damp could cause the joists to rot if rubble & dirt is in contact with the timbers.

danrv

Thanks for the reply.
It’s an upstairs bathroom.
I’ve marked the boards that need to be replaced (swollen through damp) and the ones that can stay.
The ? one was already cut but it’s in one piece from there to the wall, under the bath. 
Problem is it’s sprung up a little at the cut. I can nail it
down but only over the joist.

danrv

Sorry, have just noticed that some of the boards are tongue & groove. Only the outer sections to the wall have a normal edge which is usual I think.
Regular join is circled.

Jeepers_Creepers

Yes, the edge boards will not have a tongue as they've been cut or trimmed off to fit.

If you want to remove a T&G board without first removing the surrounding ones, you need to cut the tongues. Various ways - there are floorboard saws with funny curved blades, or you can use a jigsaw very carefully held at a shallow angle, but that needs bracing carefully - you hold it so's the blade only penetrates the 22mm-ish depth. Not for the faint-hearted. 

You could even hack at it with a wood chisel and mallet.

Are the other boards crewed down or nailed? If the former, then really best lift them all. 

When you replace them, it might also be worth gluing them using polyurethane adhesive (eg Gorilla glue) which will foam slightly and expand, filling any gaps and really locking these sheets together. 

The '?' board which has been cut along that joist sounds as tho' it needs more bracing if it isn't to keep on flexing. Is it 'tongued' into the boards either side? Best use screws to fix any down - more secure than nails - but make sure there's no pipes running over the joists first! For screwing, drill pilot holes through the boards first, and use ~50mm screws to get a decent purchase.

For that '?' board, drill these pilot holes at an angle sloping towards its cut end so that the screws can go in at a good 20mm away from that cut end (reduce risk of end breakage). Slope it at, ooh, 30o and it'll catch the joist fine. And glue it too...

danrv

Jeepers_Creepers said:

The '?' board which has been cut along that joist sounds as tho' it needs more bracing if it isn't to keep on flexing. Is it 'tongued' into the boards either side? 

It would be ‘tongued’ on the inner most edge and not on the outer. Same as the board I took out. 
This ‘springy’ area is just where you would stand getting out of the bath. Makes sense that, as covered with carpet, it has been exposed to damp for years.
Under the bath, this board is flat. It’s from the pipe/bath edge outwards that it starts to rise slightly.

I’ll see if I can secure it as suggested. Otherwise it would probably need to be cut at the next joist. 
It’s all nailed down and I could renew the lot but I’m hoping to get a good floor base while keeping a bath in place,  
Then break it up and remove just before the plasterer can start work.

Mutton_Geoff

Personally I would lift it all and replace with a single sheet of WBP. Any repair you do will make the floor more unstable as the joints will not tie the joists together. A new sheet of 18mm ply screwed to the joists will add a lot of strength and stability for whatever you are going to lay on top.

Jeepers_Creepers

danrv said:

Jeepers_Creepers said:

The '?' board which has been cut along that joist sounds as tho' it needs more bracing if it isn't to keep on flexing. Is it 'tongued' into the boards either side? 

It would be ‘tongued’ on the inner most edge and not on the outer. Same as the board I took out. 
This ‘springy’ area is just where you would stand getting out of the bath. Makes sense that, as covered with carpet, it has been exposed to damp for years.
Under the bath, this board is flat. It’s from the pipe/bath edge outwards that it starts to rise slightly.

I’ll see if I can secure it as suggested. Otherwise it would probably need to be cut at the next joist. 
It’s all nailed down and I could renew the lot but I’m hoping to get a good floor base while keeping a bath in place,  
Then break it up and remove just before the plasterer can start work.

These boards originally had T&G around all four edges so they locked fully with every adjacent board. The Ts or Gs are only trimmed off where they meet the walls. So I suspect that '?' board is T&G'd in to the two boards boards either side of it, and was also part of the 'X' board at its end - that cut was made at a later date to lay that white waste pipe. 

If that '?' board is still flexing even tho' it's T&G'd into the side boards, then it's clearly water-damaged as you suggest - and needs replacing. 

danrv

Mutton_Geoff said:

Personally I would lift it all and replace with a single sheet of WBP. Any repair you do will make the floor more unstable as the joints will not tie the joists together. A new sheet of 18mm ply screwed to the joists will add a lot of strength and stability for whatever you are going to lay on top.

Thanks for the reply. 
A single sheet of ply I would have thought, would be a problem if a leak occurs in any of the pipe work.
For a quick turnaround and access to a bath, I’d probably get a flooring pro in.

danrv

Jeepers_Creepers said:

 So I suspect that '?' board is T&G'd in to the two boards boards either side of it

It’s T&G’d on the inner most edge but not the other side (circled). Have checked 
and there’s no tongue. Does appear to be a groove though in the adjacent good board.

Replacing the board means bath out which I can do but then would be roughing it a bit.
Trying to keep the costs down but I think it would take a while to put a floor in and then get a plasterer.

Mutton_Geoff

danrv said:

Mutton_Geoff said:

Personally I would lift it all and replace with a single sheet of WBP. Any repair you do will make the floor more unstable as the joints will not tie the joists together. A new sheet of 18mm ply screwed to the joists will add a lot of strength and stability for whatever you are going to lay on top.

Thanks for the reply. 
A single sheet of ply I would have thought, would be a problem if a leak occurs in any of the pipe work.
For a quick turnaround and access to a bath, I’d probably get a flooring pro in.

That is a valid train of thought but in all my house renovation projects I had to make decisions about what is more likely. Pipe leaks are extremely rare (if the plumbing is done properly) but a wobbly floor and cracked tiles will be more of a nuisance every time you go into the bathroom.

It's usually an easier job to repair the leak by cutting open the ceiling downstairs and attacking it from below. Ceilings are an easy repair. Refixing your bathroom flooring will be more hassle whether its fitted to a nice sheet of water resistant ply or some chopped up bits of old mdf. Sometimes you have to weigh up the "what ifs" and do the job to the best standard you can.