Garage Conversion to Habitable Room - Insulation Question

[themum]

Hi everyone,

We have a garage that we are converting into a habitable room (we have all planning permission in place).

The garage is attached to the house and has a bedroom already built above it. Building control have asked us to insulate the side wall of the garage with 75mm and the ceiling with 200mm insulation.

I can understand asking insulation for the side wall as it is an external wall but the ceiling doesnt make sense. We have a bedroom above it so why would the room need insulation? Does anyone else think this iss sounds strange?

Thanks everyone.

 

[JohnD]

it might be a standard paragraph they use for garage conversions as most are not integral. 200mm is too much. Ask them to clarify the reason, and explain that there is a habitable room above.

Is the side wall a cavity wall?

 

[noseall]

bc do ask for floor and stud voids to be insulated to help with sound deadening, but this is usually 100mm insulation and normally new and not existing.

i'm inclined to agree with JohnD's explanation on this.

 

[themum]

Thank you for your replies.

John D - Not sure if it is a cavity wall. On the otherside is the neighbours garage wall too so not sure how I can tell if its a cavity wall.

Will give BC a call tomorrow!

 

[JohnD]

If you can measure how thick it is (e.g. by measuring external distance door-frame to door-frame, then deduct twice the internal distance from doorframe to surface of wall...

A cavity wall is about 13" and a solid wall about 9"

But if the house is modern enough to have integral garages I would have thought it would have cavity walls

I wouldn't be surpised if yours is made of two leafs of lightweight concrete blocks (not bricks).

 

[themum]

Thanks for your replies everyone.
Just an update - spoke to BC and the insulation for the ceiling is not compulsory and only a recommendation for sound proofing.

Thanks for your advice though.xx