Garage gym options

Evening all, after seeing a variety of threads showcasing home gym set ups over the years, I’m finally thinking about spending some money making my home gym into more than just a detached garage with a squat rack in it but the more I read, the more I realise how little I know about buildings!

The garage is detached, cavity wall construction (bricks outside, blocks inside with a void of ~150mm between), pitched roof with open eaves, concrete floor, pedestrian door and window at one end, up and over door at the other. It has electricity, but no heat source (for now)

I’m currently torn between simply painting the blockwork, adding some gym floor tiles and keeping it basic vs looking into insulating and boarding the walls and either insulating the roof, or adding a ceiling with insulation above.

Is it even worth thinking about insulation with a whacking great up an over door at one end? If so, aside from the increased cost of insulation over a basic coat of paint, what should I look out for?

If I went for the insulated option, my first thought would be to use insulated plasterboard on the inner block walls, but:

1. would doing this be a waste of the fact that the garage was built with a cavity?

2. Would I need to worry about a vapour boundary?

3. Would the top of the cavity need closing off?

4. Or would I essentially just need to create an insulated plasterboard box within the interior blockwork and below the roof, leaving the cavity and pitched portion of roof to breathe?

So many questions and I haven’t even started!!

Does it get really cold where you’re located, and when exercising, do you run hot?

Ie I can exercise in my uninsulated, open-eaved shed throughout the milder winters we’ve had down south recently.

I’m in the south west so nope, not really cold.

I’ve been lifting in there for a couple of years with the only concession being a hoody at the start of the session on occasion.

However… part of the reason for wanting to make it nicer is to convince my partner it’s a viable alternative to a gym membership for her too and she’s far less inclined to head out there on a cold day!

With mine it’s only single skin as far as I’m aware – but attached to the house with quarter of it under a bedroom. I built a stud wall down the middle of the double garage and insulated that side (the other side is the other half of the garage which isn’t insulated). I put in a plasterboard ceiling and  insulated above it with rock wall. I insulated the back of the uk and over door with solid foam insulation and put a rubber strip on the bottom of the door to stop drafts coming under it. That was ok, but then I went the hole hog and built a stud wall behind it floor to ceiling and used insulated plasterboard inside the stud wall. Stays a decent amount warmer than the insulated part of the garage in winter and stays cooler in summer. I don’t have any heating in there but it doesn’t need it as I’m always working out if in there – either weight training or turbo training.

I left the block pillar in the middle and in one corner bare block – but painted it white with masonry paint. All the plasterboard walls in plastered myself and painted white. The floor is a mixture of cheap laminate and then horse stall mats (must be about an inch thick) under the weight lifting part. I put a plastic membrane down on the floor under the rubber matting / laminate.

Been like that for years with no issues.

I diy converted our garage during lockdown

Given that you’ve got cavity walls already you’ve got a massive head start over most garages. I had to build a frame and add celotex

do you need the garage door? If not consider either sealing it up a building a celotex and plasterboard wall behind it (cheap and easy) or replacing with wall and window.

After that I’d throw up a ceiling with loft insulation above – regardless of insulation, it’ll make the room “nicer”. Never underestimate how much difference decent lighting makes to a space

after that, the floor will make a big difference- easy job to put down celotex and tongue and groove chipboard – all goes down as a floating floor so you’d be surprised how easy it is as a DIY job

do all that and it’ll be as well insulated as most 90s estate homes – I wouldn’t bother with the walls unless you’re planning to heat it round the clock.  Either spray the blockwork or get it dry lined if you want it really nice

Thanks for the replies.

Im going to focus first on sorting out a ceiling, but I’m now concerned over the weight I’ll be adding to the roof as well as adding fasteners into the trusses/joists

I’ve spent some time googling and my first issue is understanding if there’s actually a difference between a joist and the lower member of a truss… if there is, how do I know which I have?

I found a ceiling joist calculator and according to that, my joists (if that’s what they are!) are already under spec for the free span of the garage (145x35mm timbers spanning 4.4 m at 600mm centres) which makes me nervous about adding and extra load to them or adding screws…

I have a similar space to you OP, there’s no point in insulating a garage (IMO/IME) ten minutes on zwift/treadmill/huffing kettle bells about and I’m taking my top off and looking for the fan in pretty much all weathers.

If it does get really cold wherever you are then it might be worth having a small fan heater to blow some warm air directly on you (mostly if you have to change in there) but the cost of adding insulation (and presumably some type of heating system) Vs just blowing warm air directly at yourself for the handful of hours you’ll actually spend in there over a winter seems like a waste of budget you could spend on flooring and kit.

1st thing i would do is get rid of the up and over door.  They have zero heat insulating effect and insulating behind them whilst allowing a gap all around for it to open does not improve things much.

Its not cheap but i replaced our up & over with side hung UPVC doors.  With no heater other than the household boiler in there it matches the rest of the house easily with just the cheapo halfords foam flooring as an addition.  Tops off in winter and doors open in summer.

Not saying this will sort it all out but i wouldnt dream of insulating a building that has the equivalent of an open door fitted to it.

If going down the replace garage door with wall route, some estates have covenants on, ensuring the house frontages from the road remain as is.

I generally agree with the idea that insulating it is pointless.  Especially for weight training where getting sweaty isn’t such an issue.

But IME it can be too cold for Zwift.  I find that if I Zwift in winter with the big doors open and the fan on it’s like having a cold sweat.  Solvable by wearing a LS top to an extent but it’s not as comfortable as being in an enclosed space like a gym.  Those days I tend to set the big fan up pointing out the window so the air circulates but I’m not shivering in the airflow.  So it’s worth considering how you’ll be comfortable on both hot and cold days (more a question of airflow and how you direct it I guess).

They have zero heat insulating effect and insulating behind them whilst allowing a gap all around for it to open does not improve things much.

Watching the condensation run down my old one I did think it made a very effective natural dehumidifier though!