Removing internal cavity wall

24 Jan 2024
Reaction score
United Kingdom
Hi all,

I have a small utility room in a single floor extension at the back of our house. Two sides of it have a half height cavity wall, with one side then having a timber frame wall above to the flat roof, and the other side has a UPV window sitting on the outer cavity wall. The internal cavity wall appears to be doing nothing, and space is really tight.

Can I simply knock out the half height (its about 90cm high) internal cavity wall element. My plan would then be to membrane, insulate, plasterboard which would let me get more insulation in and still make the room a bit larger.

The internal cavity wall has no insulation, and a shelf across the top made from scaffolding board - it's genuinely just stood there next to the other being useless!

Any help appreciated!
Sponsored Links
If it is a dwarf wall with nothing relying on it then it is safe to say it can be removed. Just take it steady with the hammer and crowbar as it may contain pipes or cables.
Thanks Dazb - will attach a pic, but I can see in and there is nothing in there at all!

Do I need to be aware of anything damp wise - can I take it right down to the concrete floor (I'm going to put in a suspended floor anyway with insulation under it...


  • IMG_6433.jpg
    310.3 KB · Views: 29
That makes a bit of a difference as i thought it was a dwarf wall in the centre of the room and that image shows the inner leaf of the cavity wall and so has a structural element to it and will be tied to the external skin. It is still possible to remove it but as there is a door frame right next to it it may be an issue with rigidity without a solid inner leaf.
Sponsored Links
Thanks again...

No, it runs along two sides - so can I assume that through ties, no matter how low it is there will be some stability provided to the outer wall?

I am actually removing the door you can see there and intending to block it up with a timber frame. Or that is the option I am researching at the moment!

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