converting the garage. advice please

[gooberer]

Hi everyone new on here.

Im wanting to convert our double garage into a living space its 5mx5m. It is rendered on the inside and outside. There is a double window fitted and has a sink and running water. So I guess its half converted.

I need to insulate the ceiling. The rafters are 170mm so should I use 170 loft insulation? Also when it comes to boarding it should I use 9mm or 12.5mm plaster boards? Was going to use 12.5,?

The floor is concrete. Is it best to roll out dpm to be safe? And to use dpc under yhe stud work im putting up?
I was going to use 3x2 for the frames. Now is it best to plasterboard all the ceiling first then add studwork or doesn't it matter?

There are about 4 double sockets in there but would I need to get an electrician in to put them in different locations?

Thanks in advance. I guess iv got a rough idea but wanted to see what ppl thought or if I missed something?

 

[ban-all-sheds]

You might not have missed these but you haven't mentioned them so...

You might need Planning Permission.

You might need Building Regulations approval.

You might need to dig up and replace the floor.

You don't legally need an electrician, but if you doubt your ability to comply with the Wiring Regulations you should probably use one. Also if you do end up needing Building Regulations approval you might find that the practicalities of DIYing the electrics too much of a hassle.


Is it a detached garage, or part of the house? Does "living space" mean "sleeping accommodation"?

 

[gooberer]

Yes as sleeping accommodation. And yes to previous questions. It is also a detached garage with entrance from the side door as well as garage door.

 

[ban-all-sheds]

You will need planning permission.

You will need Building Regulations approval, which will mean proper insulation which will mean you can't use the floor slab as is, and 170mm in the roof will probably be insufficient.

Have you worked out what u-values you'll get from the various thermal elements, and whether they will be good enough?

There will be ventilation requirements, air-tightness requirements.

Detached accommodation like that would be pretty useless without a shower & WC, so how will you supply hot water to the former? You may need permission from your sewerage undertaker to connect a new WC.


It might be cheaper to demolish the garage and start from scratch than to try to bring it up to today's standards for dwellings.


When do you need to have it finished?

 

[gooberer]

There is no time scale. There is already hot and cold water in there so waste runs into a man hole at the side of the garage.