Vapour / Moisture Barrier stud wall

[darrena]

I am fitting a moisture / vapour barrier in to the inside of the stud wall of an internal garage conversation after fitting 50mm celetex to the cavity and foil taping it.
This is the first time I have done this as I am just a keen DIYer and wondered what method people use to attach the membrane and how they handle electrical sockets and wiring. Assuming a staple gun will defeat the objective!
Was going to use Wickes polythene barrier sheet

 

[ban-all-sheds]

I am fitting a moisture / vapour barrier in to the inside of the stud wall of an internal garage conversation after fitting 50mm celetex to the cavity and foil taping it.

That would have been enough had you used foil-backed insulation.

This is the first time I have done this as I am just a keen DIYer and wondered what method people use to attach the membrane and how they handle electrical sockets and wiring.

They are troublesome - if you've no gap between the insulation and the plasterboard then you will inevitably have to penetrate the VCL, and also compromise the insulation. (Talking of which, don't forget to use the right installation reference method for cables in insulation when designing the circuits.)

Just seal any holes in the VCL as best you can, with polythene patches, sealant etc.

What type of back-boxes are you using? Plasterboard, or metal ones fixed to studs/noggins?

[EDIT]Stoopid formatting snafu fixed[/EDIT]

 

[darrena]

Hi,

The insulation is covered in foil both front and back and I have sealed each panel all the way the round with foil tap. So in your opinion will this suffice. This build is not effected by building regs.
I have plenty of space in between the insulation and the plasterboard to fit plastic socket backing etc and if no moisture barrier required then this would pose not issue.
The room is to be used as a reptile room, not sure if this makes any difference as there will be plenty of humidity in the room.

Thanks Darren

 

[ban-all-sheds]

Hi,

The insulation is covered in foil both front and back and I have sealed each panel all the way the round with foil tap. So in your opinion will this suffice.

IMO yes, but I'm not an expert.

This build is not effected by building regs.

New circuits or a new CU will still need notifying.

I have plenty of space in between the insulation and the plasterboard to fit plastic socket backing etc and if no moisture barrier required then this would pose not issue.

You could call that Reference Method A to be on the safe side.

Dunno how much "plenty of space" is, but could you usefully have had thicker insulation?

The room is to be used as a reptile room, not sure if this makes any difference as there will be plenty of humidity in the room.

Dunno. Check on some reptile-fanciers forums?

 

[darrena]

thanks for quick response

The insulation is 50mm and the stud wall is built from 93mm x 39mm timber. I am using 12.5mm plasterboard so there should be a void of about 50mm.

I went for 50mm instulation as I was told there needed to be an air void inbetween the inner plasterboard and the insulation

 

[tony1851]

I was told there needed to be an air void inbetween the inner plasterboard and the insulation

For what purpose?

 

[darrena]

To be honest I'm not sure why I assumed it was in relation to the potential moisture build up? The wall I have built so far is in internal wall within the double garage splitting it in two so felt 50 mm celetex would suffice. I may reconsider for the external walls.

 

[ban-all-sheds]

I was told there needed to be an air void inbetween the inner plasterboard and the insulation

No.

Between the insulation and the external wall, maybe, but not on the warm side.

Still - 'tis done now, and will give you somewhere to run services.

 

[darrena]

Thanks everyone for their help it really is appreciated, I haven't done all the insulation yet so whats left I will line up with the interior to ensure the void is to the exterior wall for good practice.

So the consensus seems to be that there is no real benefit in fitting an internal vapour barrier before I put the interior plasterboard on?

Kind regards
Darren

 

[tony1851]

In that situation, a wall v.b. may not be as critical as one on the ceiling. Also, the foil on the insulation board, and the taping of the joints, should be sufficient.
Keep the place reasonably well-heated and with a little ventilation as well it should be OK.

 

[darrena]

Thanks Tony
Will the process differ much when I build a timber frame on the external brick wills?