insulating an internal garage

[nick9one1]

I have a roughly 20 y/o house with an internal garage.

The garage door is single skin metal, and doesn't seal around the edges or bottom very well.
Inside the garage the walls are airbrick, and ceiling is plastered. But there are cracks where the plaster meets the airbricks.

I feel like we're loosing quite a bit of heat due to the gaps and lack of insulation. I recently took a floorboard up in the room above the garage. I could see the underside of the garage's plasterboard ceiling, and light coming through the cracks.

I need to first seal up the cracks, then insulate or replace the garage door.

Can I have some suggestions on the best products to use?

I was thinking of using expanding foam for the larger gaps, then probably a cheap flexible caulk?
The insulated roller garage doors look like they may provide the best seal/insulation.

from outside with garage light on

cracks around edge of ceiling

 

[Notch7]

You need to take up more floorboards and fully Insulate the floor of the room above…compliant to current building regs.

it’s a bit pointless trying to stop draughts into the garage, it won’t make much difference to the ambient temperature.

 

[DAZB]

The garage ceiling should have been double boarded with staggered boards and intumescent sealant around the perimeter as it has a habitable room above it and so designed to stop fumes from a vehicle passing into the room above. It looks a relatively newly built house so was it built within the last 10 years ? If so it should still be under the NHBC Warranty period.

 

[foxhole]

The garage ceiling should have been double boarded with staggered boards and intumescent sealant around the perimeter as it has a habitable room above it and so designed to stop fumes from a vehicle passing into the room above. It looks a relatively newly built house so was it built within the last 10 years ? If so it should still be under the NHBC Warranty period.

OP said 20 years old.

 

[DAZB]

So he did, i read a lot of words after that bit....

 

[nick9one1]

Thanks for all the replies. I've done some additional poking and prodding.

The ceiling in the garage appears to have quite thick plywood backing above the plasterboard, there is rockwool type insulation above that.

something like this;

The below images are where the airbricks have been knocked loose behind an old alarm panel.
Peering through that hole I can see the floorboard of the adjoining bedroom. As this room isn't directly over the garage I presume it doesnt need to be insulated?

the orange arrow in the picture above shows the angle of the images below.

 

[Mike13]

Well you can get a draught from garage to the bedroom to the side, so that should be insulated a bit at least, not all the way across, but all the way along that joist next to garage.