Insulating a single brick garage

I have a garage attached to my house. The long exposed wall is single brick, then I have the garage door, then the other long wall is breeze block/ party wall with next door. The breeze block wall is insulated from the other side as they have converted their garage.

So I’m looking to insulate the single brick wall and back of garage door because the place is like a freezer in winter.

Done a lot of research and got confused but basic options are:
Insulated plaster board straight on wall, or fixed to batons ( which reduce overal width of course) . I’m keen to avoid dot and dab because it’s beyond me but there is a product called PinkGrip Dry Fix to stick it.

Or I could baton the wall, fill the gaps with foil backed insulation board and plasterboard over the top. One question I can’t find an answer to, is if I need a gap between back of the insulation and plaster board? The insulation has a built in vapor barrier.

Other thing is, I’d need to hang things off the wall, so either drill into batons, or drill through insulation and into the brick.

The purpose is just to make it warmer for training and bike wrenching, not for habitation.

Over to the experts…

Not an expert but I used to watch Holmes on Homes all the time. Firstly is the single skin wall exposed to wind driven rain? Without a cavity yould be on for some damp problems. Dont think you would need to leave a gap as there will be nowhere for it to ventilate too anyway.

If you want to fix stuff then a stud wall will be best. Think about where you want to hang stuff and install extra noggings and support in that area. Make sure you use a foam gasket between the concrete floor and base plate ot it could leach water and rot the wood.

Stud wall, insulation, plasterboard on top. Should be easily DIY and not that expensive.

Think about the garage door as well, that’s going to be the biggest culprit. You’ll want time draught strips around the edges and then some insulation. Make fixing some basic foil.bubble wrap type stuff will give a bit of protection.

If you are going to be in there sweating away with the heater on you should probably consider some moisture management. An extractor fan with humidistat would be a good option.


Cheers mate, yeah I read about not putting the lower baton on the floor. From what I can gather, the Celotex/ Kingspan type is stuff has the foil that acts as the barrier. I don’t think an further barrier is needed between the inside of the brick and the insulation ( the foil goes on the ‘warm side’).

I’ve read the door can be a major loss. For that it will be cheap and cheerful something Stu k on the back, as next near we will be fitting a Hormann sectional door.

Also plan to put that interlocking tile stuff down on the floor. As for extraction, I have a portable AC unit which has a dehumidifying option and extraction hose.

Also plan to wall mount a 29” smart tv in there, for ummm,vital stuff!

our summerhouse/gym/workout dungeon has no insulation, plus it has a sandstone flag floor so in winter is effing freezing - maybe 6C on coldest days without heating. I can’t insulate it 'cos there is a lot of window glass on 2 sides which is great when the sun is out, but in winter that’s a) not so common, and b) not so much thermal input.

so I invested in a 3Kw fan heater similar to this - if you slap that on about 30mins before a workout it will be comfortably warm by the time you start on the turbo or whatever else you may do in there. it’s a cheap solution but works - maybe worth thinking about? beyond power use it’s also cheaper than looking at insulation.

you can get bigger gas run space heaters - 15Kw or so - but that’s overkill imho


Second layer of bricks on the outside with an air/insulated gap ?

Why insulate on the inside when you have space outside ?

You definitely need to maintain some ventilation, like around the garage door; otherwise you’ll start to get damp/mould issues if you exercise in there.


Hmm, not a bad idea!

I was thinking insulation too, plus our boiler is in there so adding a radiator would probably be easy, but a hot fan might be much less faff and more economical.

I’ve measured -2° in there last winter. Talk about barriers to training.

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Cheers Jorgan. Yeah been thinking about that, just been out there for a solid 20mins simply trying to work out where things like a workbench (which I don’t have yet) fan, turbo etc will actually go with also leaving room for wrenching and getting stuff in and out.

The internal door at the other end leads to an entrance porch and the from door (we have another internal door that ‘seals’ the house off. I could leave that a bit open.

I rarely open our garage door, my road bikes live in the lounge and the mtb lives in the garage but I always put the bikes into the house via the front door. Maybe I’m being paranoid but I don’t plan to open the garage beyond absolutely necessary, so with no windows, ventilation would be key. I might look at getting a few air bricks installed.

I have roughly costed it out and the interlocking floor is approx £500 (plus guillotine hire) and the insulation, boards, batons etc would be somewhere between £600-650. Plus whatever a tradie charges to put my effort ups right.:laughing:

Good shout on the heater. I definitely want to do the floor as it’s nicer on the feet for one thing. I have 4 bikes and a future Moto to maintain, so plan on spending a fair whack of time in there. Just want to get it done before it gets too cold to hold a hammer!

Slight deviation, how about flooring?

I’ve got an old deteriorated concrete floor, I was going to sweep/clean it and put a self-levelling compound over it, but it appears those are for “priming” it and laying tiles or some other surface.

Any of you used something you can just pour over concrete and walk away?

I’m just going with the Ecotiles but will wait until the new garage door is fitted. had a quote for the door, fully insulated Alluguard roller door with remote, £1360.

Is that on smooth concrete?

Yeah pretty smooth as far as I can tell.

Okay, maybe I’ll just add a layer of concrete to the existing then. :+1:

Surely the roof is where the biggest heat loss is occurring? Any plans to insulate that?
You can get that spray foam stuff - either someone comes and does it, or you get DIY kits.

You can’t insulate a ply roof from the inside without putting in a shed load of ventilation and battening out between joists is a royal PITA Most flat roof insulation is done from the outside. If I do the roof, I’ll go that way.