Insulate it well and go solar hot water with boiler/ domestic hot water heater backup. The solar will keep it above ambient and make it easier to bring up to a comfortable working temps with the boiler.

There is most likely a footing under the door... it's probably there.

We typically drop the top of the foundation wall 8 to 12 inches at the door and turn down the slab...

I've got radiant heat in my 28x56 garage with a 14 foot ceiling. Heat it with a tankless gas (propane) water heater.

I've got it set so that when the floor (probe is located in the slab) gets down to 58 degrees the heater kicks on and runs till the floor reaches 61*. Once the heater kicks off the floor actually continues to warm to about 64*. This keeps the air temp ( dependent on outside temp.) between 52-58*.

I just came up from working in the garage this morning. It was 4 below (F) last night the shop was 53*.
There is a wood stove I use if I want it warmer.
I've not tried to keep it warmer with the radiant as propane is rather pricey, especially this year.

I average around $1000.00 - 1200.00 to heat it for the winter.
I did all the work myself except for the concrete. Purchased it all from this place
Radiant Heat From Radiant Floor Company - DIY Radiant Floor Heating

I think you'll find that it will be cheaper to set the temp. of the floor and leave it as opposed to turning it on and off. It takes a LONG time to heat a cold floor.
http://forums.pelicanparts.com/uploa...1393535600.jpg
http://forums.pelicanparts.com/uploa...1393535687.jpg

Please explain how you knew there was living space above the garage in the second picture?

Because it took me till post 12 before I knew there was living space above the garage.

That's what I'm thinking. Waiting to see what the insurance payout is on the C4 then I'll put a plan together

We almost bought a 2600ft bungalow with a tall walkout basement last summer... I drooled over the possibilities there. I was going to have room for 3 cars and a bar with small sitting area. With sunset-facing water views. Was pretty sad to see that one get snapped up before I had a chance to get my ducks in a row.

At our current house, I have room to tag on another 2 bays in behind, and I'm very tempted to do that sometimes... but I have the waterfront bug and could see us moving in the next couple years. I don't want to dump a bunch of money in a garage addition if I'm going to lose on it on resale, and then buy a "20 yr" house without having a garage budget!

Hard to justify leaving the heat on all week, if I get to work out there for a day or so a week. How long does it take for yours to heat up? Sweet setup, by the way!

Liking the heated floor idea a lot... There's nothing quite like radiant slab heat - it's really wonderful...

I suspect you could do slab heat with an epoxy coating although I've never personally seen it. Tile might be just as good...

Ideas, ideas...

I'm curious too. Around here it's a few days.

I'd do tile if it was JUST a workshop, but my cars are DDs and in our climate that means melting snow and salty slush. I *might* do epoxy, but I probably won't. I'm much more apt to spend $$ on a plumbing in a urinal. Sounds like I'm being funny, but I'm not

I sure hope not!! I was talking to a guy nearby who can go from -10C to +18C in about 6 hours. He's using a small electric boiler instead of a residential water heater though

Several variables. Area of slab, thickness, base temp, capacity of piping, heater rating, pump capacity... I'm on propane here, way too much operating $$ for me.

Never tried heating it from stone cold.
Ran out of propane once for about a day. Not sure exactly when it ran out but the floor was still warm (never got stone cold) around 47 degrees or so as I recall. I stayed in the garage for about 3 hrs. and it wasn't even close to getting back up to temp.
I read somewhere (probably the site I linked to) that if your only going to heat it occasionally, you should leave the center of the slab un-insulated. The ground will act as a heat sink I believe was their reasoning.

It would probably be more economical to maintain a minimum temperature and warm up from there.
It would be pretty tough on the floor to expand and contract from full cold to setpoint and back again. It may be a recipe for cracking that new floor...
Considering the flywheel effect with the mass of the floor a minimum setback temperature would be the way to go. As a side benefit, the space above the garage would also be more comfortable.
On the initial startup warm the floor very slowly.

I'd probably heat the garage with a forced air system and keep it at the temperature that I like. I'd lay on a creeper, pad, or something similar if I found the floor too cold. Or dress warmer.

Much cheaper.

JR

maybe group911@aol.com's idea of solar HW makes sense then, for keeping it at a certain temperature. I'd hate the idea of PAYING to heat it all the time.

Yeah, I have that though, and the slab is just TOO cold in the winter. I'll plan on going out, and set the time aside, but then I just can't get myself suited up to spend 4-5 hours on that floor.

Why do you spend so much time on the floor? You taking a nap?

I work in my garage every day... (in shorts and a t-shirt). It's 70 degrees out there. I find that I'm seldom on the floor. Most of the time I'm in the car, sitting next to the car on a short stool, or working on a part on one of my workbenches.

You might consider a small lift that would allow you to get under your car on a creeper. That, and some portable radiant heat would work wonders, if the air temp in the garage was comfortable.

JR

it's been 0*F or colder here for days. That slab sucks the heat right out of you, from your boots. After an hour, your feet are freezing. I've been standing and laying on cardboard for about 10 years in this garage, and I'm still cold even when I have the air at 65 degrees. Plus, I often have people hang out for "garage nights" on friday, but no one comes in the winter anymore, because they get too cold.

I'm going for a MaxJax, and have to do slab work to make that possible, so that's why I'm thinking I might as well do it all at once

The problem you are going to run into is that you'll lose heat in the slab to the surrounding soil. You can't do much about that in a re-model; at least not like you could if you were starting from scratch. It would be hard to insulate the perimeter of the slab (this really needed to be done outside of your existing foundation when it was first poured). I'm not a fan of a layer of foam under the floor, as concrete needs a supportive sub-grade. You'll be surprised at how much money it will cost you to warm the floor. I couldn't afford it.

They make electrically heated mats. Some of the anti-fatigue type mats might insulate your body if you lay on the floor. I have a radiant heater with a small fan and it makes things real cozy, if I want.

All I'm saying is that you might investigate other, cheaper options before you spend a bunch of money on a new floor.

JR

Taped and mudded sheet rock over everything on the ceiling. Fire rated. Required by code if habitable space above.

There's also probably no reason for the beam (also rocked and fire taped) if it was just a garage roof. There's probably a structural floor above supported by the beam.

You don't need any of that if there's no habitable space above.


No, I can't tell from the pic that it's fire rock as opposed to regular sheet rock, but that doesn't have to be done if it's not.

Hydronic is on the way out, take a look at electric. Call them, their website is not the best.

Radiant Heating Systems and SmartRooms by Therma-Ray
http://www.thermaray.com/images/thermaray-logo.jpg

The computer controls make it more energy efficient than the old electric, and cheaper to run than boilers.

NOTE: you may be able to place the electric tiles on the existing concrete and use the soil below as a heat sink. Call them up for expert advice.

ha! good eye!

Just measured up my square footage... I'm 660 sq ft. 23x23, with a 10x13 bump on the corner where I have my workbenches. Some smart could probably figure out how many BTUs it would take to heat that from 15* to 65*.

As it's in Canada and fire regulations vary from Province to Province (As a retired fire captain I know that to be fact) it doesn't mean there is habitable space above. It just means there is drywall on the walls and ceiling. Plumbing and electrical codes vary from province to province also.

I have a beam in my garage (22' X 24") that runs right down the middle of the garage. All that means is they didn't use engineered trusses when it was built.

Here the regulation's call for 5/8" single layer drywall or two layers of 1/2" with the joints offset and each layers joints taped and mudded. I can't tell from that picture if it's single layer or double or what the regulations are down in Eastern Canada.

If the structure wasn't attached to the house it could be lifted and new floor poured. That's the deciding factor that it's attached to the house not that there is any living space above.