Garage conversion studwork advice

[wackpac]

I am in the process of converting a new build single garage to a kitchen.
I have already bricked up the garage door and side door and created an opening for a window.

I am now starting the interior stud walls.

Is this plan ok?
Please advise if the vapor and membranes are correctly placed.
Before you ask, the BC officer said to place a course of brick under the sole plate, he also adviced to use 4x2 and have a cavity between 30 - 50mm

any advice greatly appreciated.

 

[motorbiking]

Are you not required to meet the current building regs for insulation? or will there be an external door between the converted room and the house?

 

[wackpac]

why would 120mm in the walls and 70mm in the floor to meet floor levels not meet current regulations

 

[motorbiking]

I missed the 20mm on the back of the PB.

 

[^woody^]

Why are you forming a cavity? If you do, it should be drained and vented.

 

[wackpac]

I was thinking this. but building control said a cavity is required, didn't mention to put weeps or anything however

 

[wackpac]

he did say to put vents in existing soffits but I guess that's for roof ventilation

 

[^woody^]

Shouldn't let an inspector design for you. Timber frame and an unwanted damp cavity = rot.

DPM up the wall, frame against the wall, no cavity, no problem, more room.

 

[wackpac]

Well I'm working to building regs and if the bc inspector specified that I need a cavity - should I just ignore him and hope he doesn't look on his next visit

 

[gonch69]

You really want 100mm pir in wall an 50 over don't scrimp on the insulation you'll regret it

 

[wackpac]

100mm knauf 32 is pretty high spec and an additional 20mm pir sheet over it surely is good enough.

 

[^woody^]

Well I'm working to building regs and if the bc inspector specified that I need a cavity - should I just ignore him and hope he doesn't look on his next visit

The method in my post meets building regs.

Inspectors inspect, they don't design. They have no responsibility when you have to deal with the repairs and problems a few years down the line.

The way it works is you define how you will build, and the inspector inspects it. Otherwise you end up with a second class job, worse than it needed to be, but great it passes building regs.

 

[wackpac]

can I add a dpm up the wall and still have a cavity? how would the dpm be fixed to the wall or do you mean fixed to the timbers studwall?

 

[wackpac]

my original plan didn't have a cavity but on the inspection after doing my brickwork he said a cavity IS required.

 

[wackpac]

or liquid dpm on walls?