how do I level a sloping wooden floor?

13 Aug 2006
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United Kingdom
Our existing kitchen floor has been replaced before we moved in to the property some years ago, and I can't help but notice that there is quite a slope on it.

The original floor was the usual T&G planks/boards, but for whatever reason, they were pulled out and replaced by the 8x2 floorboards.
I would like to tile the floor and also level it first. The slope is in the order of about 65mm over 2.7mtrs.

What would be the best option or way to go about this?
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hi Sonyman
You need to put down a 18mm plywood base , when the old floorboards are up see why the joists have dropped an remedy this 1st ,
subsidence ?
dont forget to noggin the joists an give the whole lot a good lash over with wood preservative , then use wood shims to level up your plywood screwed down substrate
hope this helps ;)
Thanks for the replies.
I have just checked the slope, and I see that there is a bump in the floor at about 24inches from an inside wall running parallel with bot that wall and the opposite external wall.

With a 2mtr, 4x2 lenght of roughcut timber on the floor, I could then see the bump, and the difference over about 1.5mtr was about 28mm. I couldn't go any further away as I would then need to pull out the washing machine, which is a job in itself especially when putting it back, and I didn't want to do that just yet.

I would seem that I need to lift the 8x2 boards first to see why there is a bump.
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Moz, that I wouldn't know until I lifted one of the 8x2 boards.
Just a thought now: I can get down under that floor, so I maybe could see what was wrong, if anything, from underneath???

The bump runs the full width of the kitchen: 2.2 mtrs
I think ..... if one way , if yes ,..........................susbsidece
That doesn't sound good!
But pardon me for saying so, if it were subsidence, which I am not doubting, wouldn't the floor be flat all the way, ie the fall would start at an internal wall, so the joists would fall from the next internal support.

Having a bump in the floor which starts at about 24inches in from an internal wall doesn't sound logical to me.

you are a man arent you ?
act one ... !!!!!!!!!!!!!!!!!!!!!!!!!!!! ?????????????????????????????

FFS :(

sort the flooring out an then come sort it here again ,
Sounds like Moz has been at the sauce again. You'll have to forgive him sonyman - he get's like that sometimes. He doesn't mean anything by it.....he has problems. The biggest one is his mouth. :rolleyes:
Im sorry to YOU for my mate gcol.....
if you have got A START ,!!!
Check the joists, maybe take some photos of what you find. It could be the joists are rotten or the boards have been relaid badly.
Ok, just been underneath the kitchen floor, and I'm sweating cobbs!

Now I see how it is:
All the joists run parallel to the rear outside wall, so that means that the bump actually starts from the 3rd joist in from the internal wall.

I remember now, because the new floor was spongy/springy, I decided to put some supports underneat to make it more rigid. Ok, I took the easy way and used some 3x2 timber, 1 running at 90 degrees to the joists, running directly underneath about 5 of them, and that was supported by using 3 off 3x2 vertical timbers resting on some old breeze blocks. This then made the main walk area of the floor more rigid, but at that time did not realize the slope nor bump.

I have now removed the vertical support nearest the internal wall to see if the bump would decrease, but it was only very slight.

Being a practical and logical man, I think my only option now is to lift up the joists by hammering in hardwood wedges.

Criticism appreciated.

You really need to get the floor more stable before you think about tiling it. I would recommend taking up the boards, adding new joists beside the "spongy" ones and then laying boards back. A nice new ply sheet ontop screwed down should hold it all rigid.
Static, yes I realize it needs to be more stable, as that was my original intention years ago, by putting the supports underneat.

I forgot to mention in my previous post that there are no noggins at all between any of the joists, if this is part of the problem???

How do I add new joists beside the original ones? I mean do I have to knock out bricks as per the originals, so they are supported by only the same way, at each end, or is there anopther way of doing this?

Thanks and sorry for all the questions

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