levelling an old (very) wood floor

[mulls]

Hi,
I am about to lay some laminate flooring (suitable for a bathroom - upstairs) on top of some very old floorboards. Trouble is, these floorboards are worn and uneven - I mean REALLY work and VERY uneven. My question is how should I level up the floor in preparation for receiving the laminate.

I know the best solution would be to replace the existing floorboards but I dont really want to do this as it would mean lots of work downstairs as the beams are exposed and the floorboards form part of the ceiling and general character of the house - its about 350 years old!

If I were to lay sheets of hardboard, there would be gaps beneath it in places across the floor where the existing boards are worn/damaged (some perhaps a foot in diameter) and I was concerned that this would result in too much flex in the end result. I was wondering whether I could "pack" the dips in the floor with something - perhaps carpet underlay stapled down just to present a flat enough base for the hardboard.

It's an interesting one! Can anyone advise?

Many thanks.

PS I'd rather use wood than laminate but have concerns with this in a bathroom setting - I cant find a suitable product. Is there any way I can lay proper wood in a bathroom?

 

[WoodYouLike]

If I were to lay sheets of hardboard, there would be gaps beneath it in places across the floor where the existing boards are worn/damaged (some perhaps a foot in diameter) and I was concerned that this would result in too much flex in the end result. I was wondering whether I could "pack" the dips in the floor with something - perhaps carpet underlay stapled down just to present a flat enough base for the hardboard.

You could use plywood, much stabler, and strips of thin hardboard to fill any remaining gaps between floorboards and plywood.

PS I'd rather use wood than laminate but have concerns with this in a bathroom setting - I cant find a suitable product. Is there any way I can lay proper wood in a bathroom?

Yes you can: Wood-Engineered boards with minimum of 3mm solid top layer, most are suitable for moist areas. See here or here

 

[mulls]

Thanks for the advice woodyoulike. I'll look into plywood instead but can you recommend a minimum thickness I'd need - I'd like it as thin as possible.
Cheers.

 

[WoodYouLike]

That really depends on who cupped, buckled etc your existing floorbaords are. Don't think you need 18mm, but don't use less than 10mm.

 

[mulls]

Thnx.

 

[Pewit]

Here's a tip for filling dips when laying a subfloor on an uneven surface using expanding foam - which is much easier than trying to use offcuts or foam underlay to create a level surface.

1. Cut plywood (suggest 4mm min depth) to fill the area, including some of the correct level surface around the dip - which should match the rest of your subfloor.

2. Drill 4mm holes in the plywood over the dip around 20 cm apart for suitable length wood screws to enable you to screw into the old floor and keep the plywood surface level (do not drill into the surface underneath - although you can insert rawplugs if laying over concrete or use wood hardener if the wood is poor quality).

3. Use a plant spray to moisten the are to be filled (helps the foam to expand)

4. Use the nozzle supplied with the foam canister to squirt foam in the dip (don't over do it otherwise the floor may "bulge")

5. Lay the plywood over the foam and immediately tighten the screws in the holes you have made to hold the plywood level (check with a spirit level). Check again after 1hr and tighten/add screws where necessary.

When the foam has set you can then lay the laminate over the new level floor and the foam will (a) provide support for the subfloor and (b) absorb the hollow sound.

Hope this helps

 

[WoodYouLike]

Seen this method few years ago by tiler on uneven chipboard/plywood subfloor.
After a day the whole lot looked like a mushroom farm

 

[mulls]

This is a great idea. Thanks for responding with it. I'll give it a go!

 

[mulls]

I know its been ages but I thought I'd just reply to let others know what a fantastic idea using expanding foam is. I went for 9mm ply - thats what they had in wickes and the thinner version seemed a bit flimsy to me - and followed the procedure noted. Well, almost! Anyway, the end result is great as I'm left with a flat and strong floor. Cheers for your help.