Stud work wall - how low to go

[Leoplod]

Hi all,

I need to install stud work on the inside of the exterior wall of a couple of my bedrooms. The house has a bit of an odd construction (1930s) in that the downstairs external walls are all cavity but upstairs are all solid brick.

As a result of having downstairs fully modernised and well insulated we are now getting damp problems upstairs. Basically the house isn’t as drafty as it was before.

Plan is to take both walls back to brick and build studwork off them creating an air gap with suitable insulation etc.

The question I have is - how far down should the new studwork wall go? Should it go below the floorboards? I am not 100% certain where the wall transitions from cavity to solid due to rendering on the outside. One room has carpet and insulation other is bare original floorboards with gaps between.

I was hoping that if the floors of upstairs were decently insulated the stud work could Simply finish at floor level. Any advice or opinions are appreciated.

 

[noseall]

If it was me, I would not bother with an air gap at all.
Rather, I'd fit say a 50mm sheet of Celotex directly against the wall (foil tape/foam joints) and trap it in with the stud frame. This insulation could project beneath floor level (and above ceiling) if necessary.

I'd then solid fill the stud wall and foil tape/foam fill joints then fix duplex boards to the frame.

 

[Leoplod]

Hi and thanks for the reply,

Seems to be a few methods recommended. One is dot and dab insulated plasterboard like Celotex PL4000 directly to the brick. Others say batten out, fill gaps with insulation then vapour barrier and plasterboard on top. Still others recommend, as you have, insulation directly on brick, timber frame on top then plasterboard.

Brick is 200mm thick so I don’t know if this would make a difference between which method to choose.

I like the method you recommend but am I right in thinking I would lose 50mm + batten + plasterboard and plaster in depth? Don’t get me wrong I don’t mind losing the depth - just trying to make sure I understand.

 

[Leofric]

What size studs/battens ,50mm Celotex website gives recommended technical details for insulating solid brick external walls if you want confirmation.

 

[noseall]

I like the method you recommend but am I right in thinking I would lose 50mm + batten + plasterboard and plaster in depth? Don’t get me wrong I don’t mind losing the depth

I just thought it was your intention to construct a frame regardless....

Plan is to take both walls back to brick and build studwork off them

There are plenty of methods available in which you can imrove the wall's peformance. Dabbing insulated boards directly to wall is probably the simplest, cheapest and least intrusive. It might not be the best or the one most suited though.