Mounting boxes in insulated wall

[bsr]

Hello

I have some sockets to mount on walls I have insulated with 50mm Celotex and plasterboard. I was going to reinstate the sockets by using plasterboard boxes and undercutting the insulation where the box "wings" will expand.

Is this the usual/best way forward?

Do you commonly try to chase out just to 35mm depth for the box and how do you do that? Or is it easier to cut through the board and then try to foam or glue some insulation back behind the box? I would rather not make too many holes through my new and expensive insulated wall!

PS no need to discuss derating of cables as they go through the insulation and run in an unheated loft.

Thanks

bsr

 

[sparkwright]

In the real world, one would do as you originally suggested - dry-line box and carefully cut out the insulation.

 

[EFLImpudence]

PS no need to discuss derating of cables as they go through the insulation and run in an unheated loft.

 

[ban-all-sheds]

Also, whatever you do make sure you maintain the integrity of the VCL, or it'll be mould central on the walls behind the Celotex.

 

[bsr]

b-a-s what would you do? A bead of silicone on the rim of the box as I push it in? The VCL is the foil surface of the insulation boards so I will have to go through it.