Question regarding a double skin extension with a stud wall

[lee666]

I have a 2 up 2 down with a single storey extension on the back for the kitchen and bathroom. The extension has 2 skins, with the inside having a stud wall all the way around. The plasterboard is starting to crack in the joins, possibly due to age as if it has been up as long as the extension then it's nearly 30 years old.

My question is: would there have been a particular reason why they would have chosen to use a stud wall on the inside when the extension has 2 skins? If it is of any help, both skins are breezeblocks, which I found out when fitting a fan in the bathroom.

At some point in the near future I would like to redo the kitchen and bathroom, and if possible, remove the stud wall not only to gain a little extra room but also for better support when hanging cupboards etc.

Thanks

 

[loply]

Are they full sized 2"x3" studs? Not just little battens (roughly 15mm x 30mm)?

 

[lee666]

Are they full sized 2"x3" studs? Not just little battens (roughly 15mm x 30mm)?

Hi loply, thanks for the reply. Not sure on what size studs/battens have been used. With the sizes you quoted would the 3" or 30mm be the depth of the wood? If so then the gap between stud wall and brick isn't 3" deep going from past experience of drilling into it

 

[noseall]

if possible, remove the stud wall not only to gain a little extra room but also for better support when hanging cupboards etc.

You want to down-grade a building to a single skin structure?

Sounds insane and goes against regulations in any case.

 

[Deluks]

I think he meant he has 3 skin, including the stud wall. which may or may not be attached to the inner skin.

lee, need more info!

 

[lee666]

I think he meant he has 3 skin, including the stud wall. which may or may not be attached to the inner skin.

lee, need more info!

that is correct

When I bought the house they kindly included the drawings for the extension but I don't think it states what to use for the stud wall, can double check though.

I'm just curious as to why they added a stud wall to a 2 skin extension and if it serves a purpose as if it doesn't then I'd like to remove it at some point.

 

[Deluks]

Maybe the blocks weren't particularly well laid, and a flat easy to plaster surface was required? Or for insulation? Maybe to strengthen a flimsy wall.

Do you know if the cavity between the blocks is insulated, have wall ties been used?

 

[lee666]

hi there, apologies for the late reply. I've dug out the plans left and it says the following:

Walls with 2 skins 100 conc block, render & finish to match existing. Dryline all walls with 9.5 t/e P.B on 38x25 SW treated battens with 25 jablite batts between.

Going by the above does it suggest that they were basically dry lining with plasterboard to save time, or is concrete block difficult or not ideal to plaster?

 

[ban-all-sheds]

Going by the above does it suggest that they were basically dry lining with plasterboard to save time, or is concrete block difficult or not ideal to plaster?

I am not a plasterer, but I don't think that anybody who really was would be unable to plaster, or render and plaster, a block wall.

Maybe they DIY'd the extension, and didn't have plastering skills. What's the finish on the outside?

But there's insulation behind the plasterboard, so you may not simply remove it. Not only may you not make the thermal performance of the wall worse if you fiddle with it, you'll probably have to bring it up to present day standards.

If you want to hang cupboards, using rails fixed to the studs will work.

 

[mfarrow]

I wasn't quite born yet 30 years ago, but if I was, I imagine I'd see thermal insulation of cavity walls in its relative infancy. The jablite is a bit of a give away that the construction method was chosen to enable internal insulation of the wall.

 

[lee666]

cheers for the replies chaps. at some point I'm going to need to replace the plasterboard, at least in the kitchen, as it's cracked along some of the vertical joins and along the ceiling. Hence why I wasn't sure the purpose of the stud wall given that it was a 2 skin extension.

Don't know if this is the right section to ask in, but any ideas why the plasterboard in the kitchen has cracks and not in the bathroom? Didn't know if it was due to temperature changes?

Also, would it require cavity wall insulation to bring it up to current regs, should I want to explore the possibility of removing the plasterboard?

 

[ban-all-sheds]

Also, would it require cavity wall insulation to bring it up to current regs, should I want to explore the possibility of removing the plasterboard?

Almost certainly.

Or EWI.

 

[Emeraude119]

if possible, remove the stud wall not only to gain a little extra room but also for better support when hanging cupboards etc.

You want to down-grade a building to a single skin structure?

Sounds insane and goes against regulations in any case.

Surprised me at the time, but Approved Document C of the Building Regulations shows that a 215 mm minimum thickness block (either aircrete or medium density aggregate, but not dense aggregate blocks) can be used to build a direct rendered solid exposed wall in all parts of the UK (up to and including those in areas marked as severe exposure on the BRE`s exposure map)
Where a solid wall is clad rather than direct rendered solid exposed walls can be built in any part of the UK.
To achieve the 0.28 W/m2K U-value now required under Part L1/B of the Building regulations for extensions to existing buildings, a cavity wall with a partial, or full fill insulation system in the cavity can be used. Note: some local authorities do not allow fully filled cavities to be used in their particular areas.
An alternative would be to use an insulated plasterboard e.g British Gypsum Thermaline super of sufficient thickness for 0.28 W/m2K on the internal face. or one of the newer external insulated render systems, which then allows a plaster finish to be used on the internal face.