Insulating an unheated garage to prevent heat loss in adjacent rooms?

[bobsmith2]

Hi, I've got a bedroom that sits on top of a garage (attached to the house). The bedroom has two external walls. Adjacent to this garage is also a kitchen. Now both of these rooms are generally much colder than the rest of the house. The garage appears to be a single brick skin with no insulation (the garage was possibly done in either the 20s or 60s not sure). The garage has an electric door that rolls up and inwards.

Would there be any benefit in insulating the garage with something like celotex on the walls/ceiling/floor even though it is never heated? I'm not sure if that's where the heat loss is coming from. Or would it make sense to invest in a thermal camera to understand where the heat loss is? I also presume there is no insulation in the kitchen/bedroom, but adding that in those rooms at this stage is quite hard (cost of renovations).

Thanks

 

[Harry Bloomfield]

Your bedroom heat-loss, will be via the floor, ensure the floor is insulated. The kitchen heat-loss, will be via the wall it shares with the garage - add insulation to the wall, at the garage side. If there is a door, from garage to kitchen, ensure there are no drafts and it is a decent door.

 

[^woody^]

Insulate the floor void, PIR directly under the floor and then quilt below that in the rest of the void if you like. Seal all joists and holes in the walls in the floor void.

 

[JohnD]

If you are able to lift the bedroom floor (for example it is chipboard and you are taking it to the tip) you can block the draughts by packing mineral wool between the joists, and especially round the edges of the room where most draughts come up through the gap under the skirting. Mineral wool as used in lofts is ideal as it can be pushed into irregular gaps with no precision cutting needed.

There is very little heat lost through a floor through radiation, conduction, or convection, so the draughts are your best bet. While you have it up, locate and seal gaps in the ceiling, usually round the edges of the plasterboard and holes where cables and pipes pass through. I find it is easy to seal the edge cracks by vacuuming away the dust, moistening the surfaces with a garden sprayer, and running a can of expanding fire foam along the edge.

If you're taking the floor up, this is a good time to add or expand wiring for sockets, alarm, TV, phone, LAN and speakers.

 

[westridge177]

Some good replies along the right lines, we are all advising without seeing the property, if you say that the garage is at least 65 years old the house isn’t going to have cavity walls.
For the bedroom address the floor, ignore anyone saying that the floor isn’t losing much heat. We are looking for comfort levels here. Without having seen the property the most likely route is to under draw the garage ceiling with 100mm of rigid PIR insulation with the joints taped with foil tape. The advise to address any air leakage tracks is also good. The next job is the wall insulation either internal or external. Big jobs you are not going to want to do that. Because you have two external walls your radiator might be undersized, look at putting in one with better output, maybe a double. Add a TRV. You are not going to spend much extra running it. The heat loss through the wall from a room at 21deg isn’t going to be a lot nor than from an 18deg room, and if the increased comfort means that overall you are running the heating for less time you could save money.
Kitchen, insulate the inside of the garage wall between the rooms and address heat source in the same way.

 

[JohnD]

There is very little heat lost through a floor through radiation, conduction, or convection, so the draughts are your best bet.

 

[westridge177]

There is very little heat lost through a floor through radiation, conduction, or convection, so the draughts are your best bet.

As I said in my reply DO address draughts and DO ignore people telling you that there is little heat loss through the floor, we are looking comfort levels and by insulating under the ceiling you are producing a bedroom floor at closer to ambient temperature rather than at closer to outside temperature. I’ve been designing and creating luxury home renovations for 40 years, it’s the little things that can make a difference.

 

[Harry Bloomfield]

if you say that the garage is at least 65 years old the house isn’t going to have cavity walls.

Then you would be wrong....

Cavity walls have been in use since the late 19th century. 65 years ago, they were quite common. My own home is 70 years old, and certainly does have cavity walls.

 

[westridge177]

Then you would be wrong....

Cavity walls have been in use since the late 19th century. 65 years ago, they were quite common. My own home is 70 years old, and certainly does have cavity walls.

Ok, for clarity to the OP who we are supposed to be helping (rather than getting Pedantic with each other)
“Based on the age of the house it is unlikely to have cavity wall insulation “

 

[Harry Bloomfield]

Ok, for clarity to the OP who we are supposed to be helping (rather than getting Pedantic with each other)
“Based on the age of the house it is unlikely to have cavity wall insulation “

We just haven't been given any clues about the house, at all, other than it having an attached garage, built between the 1920's and 1960's. Quite a wide range, and it wasn't clear whether it applied to the house, or just the garage.

Perhaps the OP, could post a photo of an outside wall of the house, then we would be able to easily determine whether it was a cavity or not?

 

[westridge177]

Or maybe just move on. The presence of a cavity will make no difference in any case.