Stud Wall, Kitchen

[loopy66]

I have an external wall on the side of a kitchen, only approx. 2m² in size, it's single brick and the internal side of it is absolutely terrible, boarded with crappy thin chip board, electric wires visible on the outside and just general grubby. I need to take it back to the brick and make it good.

I am thinking make a stud wall, insulate, plasterboard and skim it.

My questions are, do the layers go like this...

... brick -> stud timber (with insulation in the space) -> vapour membrane -> plasterboard

... or can it go like this...

... brick -> stud timber (with insulation in the space) -> moisture repellant plasterboard

... ie, the 2nd option is giving the vapour control layer and the plasterboard.

With the above in mind, does there need to be any air gaps behind or in front of the insulation and also, there are some pipes an electrics on the wall, can I run them in front of the insulation but behind the vapour control an then just pop them through the plasterboard where they need to come out for the sockets?

 

[^woody^]

Search the garage conversion threads, there are several options

 

[John D v2.0]

Don't confuse moisture resistant and foil backed plasterboard. Moisture resistant is basically to support tiles in a bathroom, foil backed is to reduce the vapour openness.

 

[loopy66]

Will the garage methods 100% apply, I was wondering if there is any different considerations as this is a kitchen?

Regards the plasterboard, might be worth fitting them just in case tiles are wante at some point but, option 1 looking like the actual layers needed still then.

Any advice on the this would be much appreciated... especially about any air gaps that might be needed and how to deal with the service pipes an wires.

 

[^woody^]

The principles are exactly the same.

 

[loopy66]

I have been searching through an building up a picture. In the meantime, I am also thinking that there will be a cooker in front of this wall so, should I use the fire retardent plasterboard?

 

[^woody^]

No. All plasterboard is fire retardant.

 

[John D v2.0]

The tiles thing, any plasterboard will support tiles, just normal plasterboard will collapse if it gets wet as the paper is the structural element, so you wouldn't use it where water sprays it.

 

[loopy66]

I am detecting the producers are making money of the not so well informed here A bit like the Gilette razors when they produced the vibrating razor and the non vibrating razor... the spare razors for the vibrating razor were twice the price of the non vibrating spares but a marketing lady from Gilette told me they are exactly the same but a different colour. A similar thing happened with some pain killers... £3 or whatever for a normal pack but the pink pack which said "fast acting for period pains" was £6... exactly the same tablets inside.

 

[John D v2.0]

to be honest building is actually quite technical, yes you can use standard details but once you go off that you need a lot of qualifications and/or experience to design something fancy. Once it get's too expensive to over engineer it, you hire a designer and pay them less than the money you saved employing them.
In your case you're lucky it's pretty standard, ideal option external insulation and rendered over.
failing that if the wall is dry I'd do A with no air gap.

I did exactly that (75mm celotex between 70mm studs, foil taped and a poly sheet stapled over, then plywood then shower panels). But as you can guess it's in a shower cubicle so the VCL is all the more important.
If you do start with an air gap on the cold side of the insulation, you're supposed to start draining and ventilating it, which would be difficult.

 

[loopy66]

I believe the wall is dry and to be honest, this just needs to be a really quick job to get "something" decent before a complete structural refit in a few years; honestly, the current wall was put up by a blind guy I think, it's absolutely horrendous.

Option A in my first post seems to be the most common from all the searches i've done, my only issue I need to confirm now is, electrical wires and pipes seem to need to go between the insulation and the vapour control layer but then, i'd need to cut holes in the layer to bring the wiring through and then I am thinking, that puts a hole in the vapour layer and then what's the point of this layer?

 

[John D v2.0]

the holes make the layer less effective but not useless. You are just trying to reduce the vapour permability on the warm side to be less than the permeability in the colder layers.
You can go to great lengths doing condensation risk analysis but it will be cheaper to just put all the wiring on the warm side, in my case I just spent the time sealing everything with tape