sloping wooden floor in upstairds bedroom - best way to correct?

18 Feb 2021
Reaction score
United Kingdom
Hi all,

We were hoping to get some advice about a sloping floor. We're planning to re-do the floor in our bedroom on the first floor of our terraced house. We will remove the carpet and we want to lay a wooden floor, on top of the existing wooden planks which are screwed into the joist below and which we don't want to replace as they are in good shape.

The problem is this: the floor is sloping. From one end of the bedroom to the other there's 6 cm difference in height, over ca. 4 meters in length. This is also apparent on the landing and in the other bedroom.

The underlying cause is not that the existing wooden floor or the joist below are bad or rotting. They all seem in good shape. It's more likely caused by the whole house being slightly 'sloping'. We measured the windows and walls on the first floor, and they are at a slight angle, though less so than the floor. In the past there's probably been some subsidence, but our surveyor said this was of no concern for the future.

Our house is standard construction, with wooden joist supporting the floor, and it's from the 1920s or 30s.

Our idea to fix this issue is to leave the joist and existing wooden planks in place, and to use shims and sheets of plywood to raise the low spots and create a new level surface. We would screw and glue these shims and plywood to the joist below (through the existing wooden planks), and then lay our new floor on top of this.
This is more or less what we plan to do:

Question: is this a stupid idea?

One disadvantage is that once the floor is level, the walls and windows will still be at a slight angle. I wonder if this will look weird, especially when we sell the house in the future.

We would really like to avoid having to remove all existing wooden planks and increase the height of the underlying joist, and then putting the planks back. Any thoughts?

Sponsored Links
Suggest you look at "firring pieces" [very long thin triangular especially cut, bits of joist ] laid on top of the existing flooring then new flooring.

Or?? lift the existing flooring [and skirting] --- needed in both cases--- fix the firring, re-lay the existing floor board, a lot will depend on their condition?

Possibly ?? a cheaper option ?

Yes, you will notice the walls and windows to start with but will get used to it.

Laying chipboard on firring pieces seems at least as much work as lifting the existing boards, taking account of skirting removal and boards continuing into the adjoining landing. You will also have a step up if the room is higher at the entrance. If you do board it, get any cabling or pipe laying done first as it is a lot simpler and neater for the trades to lift a floor board than cut through chipboard, firring piece (possibly), and then through floor board.

My own take is that 1/2" a metre rise (or just over) is absolutely fine to live with. It's part of the character of the property, and indeed of many more properties (new and old) than you might imagine.

At least if the missus breaks a beaded necklace you'll be able to find all the beads.
Sponsored Links
If you want a yardstick in terms of level, I sugestbthat you look up "The Crooked House" at Himley near Dudley. That will give you an idea about how far "movement" can take you

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