I have a 1 car detached garage built in the 50s here in WI. I recently have insulated and have a blue flame vent less heater. The foundation is exposed from 6 to 16 inches in the rear. When heating the garage, it will be 65 at 4 ft and freezing on the floor. What is the best economical way to fix? Insulate the foundation? With what and how deep? TIA.
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Insulating garage foundation
- Thread starter JC2lite
- Start date
You're only heating while out there ?
The difference is the cold concrete.
The difference is the cold concrete.
jonesg
Well-known member
I solved it with electric heated socks. Its easier and cheaper to heat your feet than the concrete.
You're only heating while out there ?
The difference is the cold concrete.
Thermal mass is a hell of a thing to overcome.
OP, if you're pumping heat in 24/7 eventually the concrete will get up to temp (in theory, as long as heater is large enough). Insulation will help here as it will reduce the heat transfer through the concrete.
Heating periodically, you're going to need insulation and a big enough heater (or time) to warm a very large amount of cold material.
Your best option may be to frame our a small wall along the taller concrete and insulate 6" thick.
I try to keep it above 40 when not out there.You're only heating while out there ?
The difference is the cold concrete.
Thermal mass is a hell of a thing to overcome.
OP, if you're pumping heat in 24/7 eventually the concrete will get up to temp (in theory, as long as heater is large enough). Insulation will help here as it will reduce the heat transfer through the concrete.
Heating periodically, you're going to need insulation and a big enough heater (or time) to warm a very large amount of cold material.
Your best option may be to frame our a small wall along the taller concrete and insulate 6" thick.
Yes. This is why I try to tell people, keep the heat in the 'crete.
I was thinking maybe putting insulating panels on the crete and do a raised bed around the garage. Thoughts?Thermal mass is a hell of a thing to overcome.
OP, if you're pumping heat in 24/7 eventually the concrete will get up to temp (in theory, as long as heater is large enough). Insulation will help here as it will reduce the heat transfer through the concrete.
Heating periodically, you're going to need insulation and a big enough heater (or time) to warm a very large amount of cold material.
Your best option may be to frame our a small wall along the taller concrete and insulate 6" thick.
Outside?I was thinking maybe putting insulating panels on the crete and do a raised bed around the garage. Thoughts?
Sounds like a waste to me, as your still heating a mass of concrete from 40 to comfortable whenever you work.
I was thinking it would help the concrete stay warmer.Outside?
Sounds like a waste to me, as your still heating a mass of concrete from 40 to comfortable whenever you work.
Adaylate
Well-known member
As you know the time to address this is when the building is built.
But I noticed an architect here, building his office, put rigid foam against the outside of his high stem wall. Then he bermed dirt against it. I don't know what kind of rigid foam but I'm sure a search could find it.
This sounds like your raised bed idea.
Good luck!
But I noticed an architect here, building his office, put rigid foam against the outside of his high stem wall. Then he bermed dirt against it. I don't know what kind of rigid foam but I'm sure a search could find it.
This sounds like your raised bed idea.
Good luck!
It will but you still need more heat in there to constantly keep the concrete floor warm.I was thinking it would help the concrete stay warmer.
Is your ventless, NG or LP ?
I'll give a real word example as.im sitting in my shop.
1200sqft walk out basement. Back 3/4 is underground, With 2' or so exposed at top of wall. Front 1/4 is fully exposed on one end, with a garage door, and heavily sloped on the sides with a lot of wall exposed. No buried insulation as far as I know, nothing indoors.
With yesterday's high being 8F, I kept the basement at 60F with a 25k BTU pellet stove. I used a 50k BTU non-vented propane heater for 15 minutes to get it up to 70 so I could do some painting, and the pellets held that for several hours.
If I had run just the propane, I would have struggled and put enough moisture in the air to get 1" of frost on the exposed concrete (did this several times prior to getting pellets).
The cold seems to win with exposed to the exterior concrete.
1200sqft walk out basement. Back 3/4 is underground, With 2' or so exposed at top of wall. Front 1/4 is fully exposed on one end, with a garage door, and heavily sloped on the sides with a lot of wall exposed. No buried insulation as far as I know, nothing indoors.
With yesterday's high being 8F, I kept the basement at 60F with a 25k BTU pellet stove. I used a 50k BTU non-vented propane heater for 15 minutes to get it up to 70 so I could do some painting, and the pellets held that for several hours.
If I had run just the propane, I would have struggled and put enough moisture in the air to get 1" of frost on the exposed concrete (did this several times prior to getting pellets).
The cold seems to win with exposed to the exterior concrete.
WisJim
Well-known member
I would put 2" styrofoam or equivalent around the outside of the foundation down a minimum 2 feet below the surface and up to cover the concrete. Cover with the fiberglass or similar material made to cover exposed foam or use aluminum coil stock to cover it. It should be possible to dig out enough (in warmer weather) by hand to install the foam. I did it around our old farm house years ago.
paulsomlo
Well-known member
Agreed - the accepted way to insulate a slab already laid is to insulate the slab edges.I would put 2" styrofoam or equivalent around the outside of the foundation down a minimum 2 feet below the surface and up to cover the concrete. Cover with the fiberglass or similar material made to cover exposed foam or use aluminum coil stock to cover it. It should be possible to dig out enough (in warmer weather) by hand to install the foam. I did it around our old farm house years ago.
Monza Harry
Well-known member
I added 2" pink hard Styrofoam to my basement walls during another run away project. [ran electrical, water, gas and an empty conduit for alarm/data, and future unkowns] I felt an immediate improvement in the basement, but that diminished quickly. After the internet became way more accessible and filled with more complete info. [project was late 90's, internet but many searches brought little to no relevant info.] I found out that Styrofoam will eventually absorb moisture. So there is a liner that can be placed against the foam [not that I could find] and then "Delta MS", BigO" etc. for drainage. Going forward if I am forced to re-dig I'll remove and place in the sun to fully dry it out then I'll do some basement damp proofing on all of the exposed sides and may even try to adhere the foam with it as well.
As for the depth at least to 6" below the frost line for any reasonable insulation effect. Just my experience. Harry
As for the depth at least to 6" below the frost line for any reasonable insulation effect. Just my experience. Harry
LPIt will but you still need more heat in there to constantly keep the concrete floor warm.
Is your ventless, NG or LP ?
I would be curious as to cost/usage for the LP to set the thermostat to 50°.
Fully insulated, including garage door? Walls and ceiling covered with drywall, plywood or OSB ?
learningmore
New member
- Joined
- Mar 15, 2022
- Messages
- 1
I was thinking it would help the concrete stay warmer.
You are correct!
Adding rigid foam above and below grade helps significantly to keep your foundation warm.
I was surprised to learn that for many areas, the ground is warmer than the air.
So, the rigid foam on the edges of the foundation helps to trap in the existing heat in the ground. Also, adding rigid foam
There is a method called "Frost Protected Shallow Foundation" (FPSF) that uses rigid foam insulation on the exposed foundation edges, and also extends into the nearby ground. Here is a link to Detailed PDF from National Association of Home Builders, 2004. They offer some helpful diagrams to explain how the rigid foam traps in the heat, and protects from the cold air / frozen ground.
Note that this method with a shallow foundation/footer is only approved for use in "heated buildings".
I used the FPSF method for a detached (heated) garage, and instead of digging a 24" deep footer, I only needed a 12" deep footer, which saved excavation costs. (Actually, in my zone I wasn't even required to use rigid foam- but I will, to keep heat in my slab, and to save heating / cooling costs.)
Charles (first post!)