Sloping wood floor?

[kajat]

I have a 190? mid terrace and want to replace the dated upstairs bathroom which is at the back of the house on the 1st floor. Trouble is I have a slope off towards the rear wall of about 4 inches over the length of the room (around 2.5m). I assume this has been caused by subsidence many years ago, as the survey did note this, but said there was no signs of recent movement.
I lifted the boards and the joists seem sound.

Can anyone suggest the best way to level the floor, ready for fitting my new bathroom and tiling.

 

[freddiemercurystwin]

Assuming you're laying tiles on the floor you'll need to put a layer of ply or similar down so you could just stick tapered furrings (battens) to the top of the existing floor (fixed through the existing boards into the joists) If that buggers up your floor level at the door it sounds like you'll have to discard the existing boards and then stick the battens directly onto the existing joists ready for the ply on top.

 

[kajat]

Freddy thanks for ultra quick reply,

I should have said in original post....The slope is away from the door towards the back wall and the joists run across the room (each joist getting progressively lower), so tapered 'furrings?' straight onto the joists are a no go.

I assume it would have to be different thickness battens on 4 of the 5 joists, but wouldnt the batten at the one nearest the level be too thin to be stable?

I did find an online article about screwing 'new joists' to the side of the old ones to bring the level up. That seems rather drastic, but do you think maybe that's the solution?

 

[freddiemercurystwin]

Ok, what about if you just fix progressively thicker battens on top of your existing ones (inline with them)? If all they're doing is acting as packers you could safely go down to only a few mm.

 

[kajat]

On top of the existing joist you mean? I think maybe I will give that a try. It sounds like the easiest option don't you think?

Although laying the ply on top of the boards ready for tiling will raise the level too much at the door (as you suggested), so I will discard the boards and go with ply only - any idea on minimum thickness?

 

[freddiemercurystwin]

Yea on top in line with each joist. Probably best to go as thick as possible, say 25mm min. (its only going to be a minor cost compared to the cost of you're whole bathroom), glue and tongue & groove the edges if you're using more than 1 sheet to ensure you don't get any tiles lifting or cracking. And lots of fixings. If theres any bounce in the floor you could consider a flexible adhesive/grout just to be safe.

 

[kajat]

Many thanks freddy