Insulating a garage

bloodline76 · 2 May 2024 at 15:05

I have some home gym in the garage and the cold has been difficult to motivate me over the winter so I am interested in putting in some insulation to help retain some of the heat. From the few videos I have seen online it looks like I can probably manage it.

The garage is connected to next doors garage. The end has brick, then a gap, then breeze blocks. I assume the same is for the sides.

1. Create a partition wooden frame, double the thickness of the insultation (Not picked yet).
2. Attach a vapor barrier to the back of the frame and underneath all areas touching the floor/walls.
3. put the insulation in the frame
4. Cover the insulation with either plasterboard or wood/board

This is the first job, then repeat for the roof/ceiling

Sound correct? Happy to be educated

Thanks in advance

SPG · 3 May 2024 at 12:36

If you have a double skin wall, it might be worth getting a quote for cavity wall, and then just some thermal plasterboard.

SoliD · 3 May 2024 at 13:45

unlikely the garage would be built with a cavity all the way round unless it's attached to the house.

What you've suggested is possible, i'd go down the celotex/pir route and just tape the edges, no need for vapour barrier then.

Whats your garage door like as this will be the next piece of the puzzle and will be leaking heat once you do the walls and ceiling. Also whats your plan to heat the space as if you're just hoping to retain the heat from your body during workouts dont expect it to ever be warm.

bloodline76 · 3 May 2024 at 16:06

SoliD said:
unlikely the garage would be built with a cavity all the way round unless it's attached to the house.

What you've suggested is possible, i'd go down the celotex/pir route and just tape the edges, no need for vapour barrier then.

Whats your garage door like as this will be the next piece of the puzzle and will be leaking heat once you do the walls and ceiling. Also whats your plan to heat the space as if you're just hoping to retain the heat from your body during workouts dont expect it to ever be warm.

I have done the garage door from top to bottom in the insulation foil. Put a draft excluder at the bottom, it shuts out the light, so much better than before.

It is attached to the house and then someone elses garage on the other side. So I am guessing there is a cavity on three sides. No insulation in there from what I can see.

Can you elaborate on the celltex/pir route? I am googling and youtubing all this

Bit question I have is about ventilation. If I did the roof/ceiling should there be no gaps, or does some air need to get in?

bloodline76 · 3 May 2024 at 17:57

Celltex pir googled. So basically create a wooden frame with no gap and put the celltex in the gaps?

Sounds a lot easier. Will this cause any issues with condensation?

dlockers · 3 May 2024 at 18:03

bloodline76 said:
Celltex pir googled. So basically create a wooden frame with no gap and put the celltex in the gaps?

Sounds a lot easier. Will this cause any issues with condensation?

Glue the PIR to the wall using spray-on foam glue, and then put your wood battens in front. This means that you are totally enclosed in insulation then. PIR is covered in a layer of silver tape so it is already a vapour barrier and will keep moisture on the other side.

https://i.imgur.com/O2PI8Rc.jpg

^ I couldn't find a better in progress pic but you can see left hand side the PIR on the wall and then the batten on top.

bloodline76 · 3 May 2024 at 18:07

dlockers said:
Glue the PIR to the wall using spray-on foam glue, and then put your wood battens in front. This means that you are totally enclosed in insulation then. PIR is covered in a layer of silver tape so it is already a vapour barrier and will keep moisture on the other side.

https://i.imgur.com/O2PI8Rc.jpg
^ I couldn't find a better in progress pic but you can see left hand side the PIR on the wall and then the batten on top.

Thank you. Then put board in front of it?

Mason- · 3 May 2024 at 18:26

Look at kingspan K118. It is insulated plasterboard with 2 vapour barriers built into it. Could save you a few processes.

dlockers · 3 May 2024 at 18:45

bloodline76 said:
Thank you. Then put board in front of it?

Yeah or no board at all depending on what look you are after.

As Mason said, another option is to use insulated plasterboard and then you don't need to board at all. It it what I am using in my front bedroom project and clad the cold sides of my bathroom in that weren't covered:

https://i.imgur.com/qpauNZR.jpg

bloodline76 · 3 May 2024 at 18:45

Mason- said:
Look at kingspan K118. It is insulated plasterboard with 2 vapour barriers built into it. Could save you a few processes.

Thank you, appreciated.

bloodline76 · 3 May 2024 at 18:46

dlockers said:
Yeah or no board at all depending on what look you are after.

As Mason said, another option is to use insulated plasterboard and then you don't need to board at all. It it what I am using in my front bedroom project and clad the cold sides of my bathroom in that weren't covered:

https://i.imgur.com/qpauNZR.jpg

Thanks for the advice guys. Appreciated.

bloodline76 · 3 May 2024 at 18:48

So if I did the ceiling too, I would seal it all? No gaps for ventilation?

dlockers · 3 May 2024 at 18:55

No random gaps for ventiliation. If you really need it, fit a heat recovery fan (Gosforth did a video on these) or some other kind of PIV system. Won't you want some kind of AC?

Remember insulation maintains temp like a thermos so it'll keep whatever is inside hot or cold. Any heat generated in it, will stay in it.

bloodline76 · 3 May 2024 at 19:07

dlockers said:
No random gaps for ventiliation. If you really need it, fit a heat recovery fan (Gosforth did a video on these) or some other kind of PIV system. Won't you want some kind of AC?

Remember insulation maintains temp like a thermos so it'll keep whatever is inside hot or cold. Any heat generated in it, will stay in it.

Thanks, will have a look for that. Its main use will be a home gym. Too hot open door. Too cold I have a small fan heater.

But will have a search Gosforth video. Thanks again.

dlockers · 3 May 2024 at 20:11

What's the floor like? If it doesn't have a DPM it'll wick moisture up.

bloodline76 · 3 May 2024 at 20:40

Mason- said:
Look at kingspan K118. It is insulated plasterboard with 2 vapour barriers built into it. Could save you a few processes.

If I went with this do I put a frame up and put it on the outside like you would plasterboard?

dlockers · 3 May 2024 at 20:41

bloodline76 said:
If I went with this do I put a frame up and put it on the outside like you would plasterboard?

The same as what I posted, just glue it to the wall. https://i.imgur.com/qpauNZR.jpg

bloodline76 · 3 May 2024 at 20:50

dlockers said:
The same as what I posted, just glue it to the wall. https://i.imgur.com/qpauNZR.jpg

Thanks for confirming.

Reuben klang · 3 May 2024 at 21:47

I’ve just done mine in the last few weeks.

Frame ceiling out first, if it hasn’t already, you’ll get away with using glasswool/rockwool etc use the smaller sheets for the ceiling don’t use the 2400x1200 they’re a nightmare to lift above your head.

Once ceiling is done, get DPC and staple it to the back of your rough sawn timber battens, you don’t need anything fancy. Don’t get CLS etc

Get a box or two of concrete screws and frame those walls out. Get Insulated plasterboard and screw it to the timber.

Job done.

If you don’t have a collated screwgun, get one. You’ll need 50mm screws for it to go through the 37.5mm PIR plasterboard. It’ll also be a life saver if you need to do the ceiling.

Freakbro · 4 May 2024 at 08:03

I've converted half our double garage into a music/cinema room and used celotex on the walls and under the floating floor, nothing on the ceiling (fibreglass in roof space) 1 radiator in there and it's now the warmest room in the house