Levelling upstairs floor

11 Jan 2013
Reaction score
United Kingdom
Another little job at the House of Pain- over its 200 years it has acquired a bit of a lean- the bedroom floors are 70mm lower one side than the other (the drop is across the joists, it is the walls that have sunk not the timber). There is a bit of sag in the middle of the joists (about 10mm) but other than that they're in decent condition.
So I'd quite like a flattish floor- is 18mm OSB on edge good enough to support floorboards (and stiffen the joists a bit) or does it have to be 25mm ply? The existing joists are about 200 x 75 on a span of 4000 ish, looking at plating them all with (minimum) 200 wide bits of OSB/ply/whatever as a quick easy way of getting a flattish floor.

Actual floor covering is tbc at the moment- if I can find the cash it'll be 20mm T & G redwood, if not it'll be 18mm T & G chipboard. Where I need to join boards, I'll just sister a bit of OSB/ply to the main plate to give me room for fixings

Ta all
Sponsored Links

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local