INSULATING A GARAGE WALL

[SJFK]

Can anyone help? I have an integral garage, and the joining wall with the house is unrendered breeze block. I would like to insulate it and would like to know which is better, spray foam or something like celotex boards.
If Celotex boards then how do I fix them to the wall? Do I need to batten the wall first? I am trying not to lose too much of the width in the garage so spray foam seems good, but does it have the same thermal properties as the Celotex?

Any advice would be welcome.

SJFK

 

[stem]

You don't give details about the actual construction of the exterior walls of your house. For example is it solid or cavity? or why you want to insulate this relatively small piece of wall, which will be insulated from the cold, wind rain snow etc., by the garage to a large extent anyway.

Normally the wall between a house and integral garage is the same basic construction as the rest of the exterior of the house, if so & it's;

A. Insulated cavity, the only difference is that the external skin is "breeze" instead of brick as being inside the garage it's not directly exposed to the weather. If this is the case, insulating the wall inside the garage will make little if any difference, it's already done.

B. Solid, (not likely with breeze though) insulating a small area of wall (as compared to the whole of the outside surfaces) will make little difference to the house as a whole.

 

[SJFK]

Stem,

The outer walls are cavity. I am not convinced that this garage wall is a cavity wall as well. But the issue here is that the garage is cold, not draught proofed which would be difficult to achieve, and the garage door is open quite often. I believe the garage pulls a lot of heat out of the house, and even if it is not as bad as I think, it will still account for some heat loss. So I am trying to find the most effective way of preventing what heat loss there is.

thanks

SJFK

 

[stem]

British Gypsum produce a product called Gyproc Thermaline. It comes in various types and consists of plasterboard bonded to expanded polystyrene. It can be fixed directly to existing walls using blobs of Gyproc Sealant. (I imagine that Knauf & Lafarge also produce similar products)

A friend of mine used it to insulate the inside of his external walls because they were solid not cavity. It made a significant difference, but as it's quite thick expect to loose some internal space.

Caution is needed if the insulation covers cables too. Some cables may have to be replaced with a larger size to prevent overheating.

I might be wrong, but would be very surprised if your garage walls weren't cavity. Assuming you're not in a bungalow, surely if the wall extends upwards to become the cavity wall outside of an upstairs room. It must be the same below in the garage to support it. I would drill a test hole through the wall to see. I'm not a builder, but in my experience (ex-electrical installation) I have not come across a modern (1960's on) house with an attached garage that does have a cavity wall between the house and garage.