Leveling up existing timber floor

[joydivision]

Not really my bag this, give me a trowel any day!
Anyway, job I have kind of got involved in. A dividing wall between kitchen/diner has been removed, and existing downstairs timber joist/ board floor is out of level, up and down everywhere. Highest point to lowest is 25/30mm.
Leveling the joists up will help but probably wont get it spot on as I think the joists are probably warped anyway, explaining all the humps and dips.
Is there an alternative to ripping up the floor and joists?
I have noticed a floor leveling compound for timber floors, anyone have any experience of this?

Cheers

JD

[GB_Groundworks]

Hardboard or 6mm ply then relay floor

What's going to be the floor covering?

[joydivision]

Either real wood t&g flooring or amtico or something similar. Wouldnt 6mm ply once fixed will only follow the current contours of the floor? And I would still be out of level by a good bit as at the moment its 25mm ish out.

Cheers

JD

[GB_Groundworks]

No you fill the follows and dips then board over it with hardboard then lay your new floor on a foam insulated Matt.

It's that or get underneath and prop the low ones with slate etc

If its getting a new floor doesn't matter cutting into it

[rab1]

run some new timber against the side of the floor joist and level the new timber and fix into the original joist and repeat at each original floor joist. you will need at least 75mm to allow joining of new timber to side of existing floor joist for structural strength. do it once and do it right.

[London Stone Paving]

Thats good advice rab. i need to do something similar with my kitchen ceiling and the same principals apply i assume

[joydivision]

yeah agreed, great shout. Was trying to avoid taking up the floor as I thought I would end up re-doing the joists, but thats a pretty easy and good fix.


Cheers

JD

[rab1]

only way to do it but fix the new and old timbers every 12".

[rab1]

you can use less of an overlap on a ceiling Steve as the weights involved will be a lot less.

[gonchy]

if the cielings coming down pack up low joists if not and and you take up floor to plant on the sides of original run some pva on the joint and screw the timbers as the last thing you want is sqeeks which you will get with no adhesive and nails also to consider once floor is up will the old boards still be usable becouse you could replace with chipboard and use a caber deck adhesve or http://www.ecobuildingsystems.co.uk/item/egger-d4-adhesive

as these do take up slight veryations in levels and only a couple of fixings in each board needed

[rimexboy]

when my ceiling in my kitchen was all over the place on levels the guys on here said fir sister joists onto the old ones getting them level as you go..

good advice on a ceiling but for a floor alot more work is involved as you need to lift all the floorboards fist..

simon