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Heated garage floors -pros and cons??


kreed
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I am in the planning phase of building a facilty for my cars and have been looking at the pros and cons of heating the floors . Researching this on various sites has resulted in lots of conflicting opinions . Obviously expense is one of the key factors - quotes of $5-6 SF which is above the cost of the concrete . Would love to hear of anyone's experience -good or bad . Thanks and hope everyone has a wonderful Holiday .

KReed

ROA 14549

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Not good if usage requires rapid heat up of the space.

if you can set it at one temp and leave it there that's best. Nice thing is no dust or noise created by forced air blowing. 

With a heated floor you'll want to lay down on it and take a nap. 

With the combined effect of extra insulation under concrete when a heated floor is installed along with the heat source in the floor it makes for a nice dry environment with no moisture coming from the ground. I am fortunate to have my car in a garage with heated floor and its wonderful. 

One more thing.  It's a common practice to saw cut a concrete floor for controlled expansion cracks. Saw cutting is dangerous on a floor with water hose every few inches so the contractor needs to make provisions for this. The garage where my car is is 30x50 and the contractor chose to not saw cut it. There were a bunch of hairline cracks after curing but it was being covered with porcelain tile so didn't matter. A friend had a geo thermal heated floor in his garage and the contractor cut a water line rendering that circuit useless. 

Edited by JZRIV (see edit history)
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I suggest you look through the "Garage Journal " forum.

 

http://www.garagejournal.com/forum/

 

This is discussed in detail.

 

Yes, there is a lag in heating. You need to start heating the slab well before you want the heat.  But once you do, it is really even and steady.

 

I built a 35x48 garage a few years ago and investigated heating the slab before pouring it,  It depends a lot on where you are (how cold it gets and for how long) and what your heat source is going to be (natural gas, electric, etc.) to decide if it makes sense.

 

I decided not to do it.

 

 

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I installed a heated floor when I poured my garage floor. I did all the prep and brought in a crew to do the actual pour. There are detailed considerations when laying out the tubing.

Concentrating the coils in the areas of higher heat loss like under windows or doors is good practice. One little trick I used was to charge the circuit with air pressure while doing the pour. If a worker accidentally punctures the tubing with a shovel, etc during the pour there will be a small "eruption" in the pour! A large coffee can or bucket can be used during such an occurrence to isolate the immediate area from concrete to be repaired and filled later.This is also a good troubleshooting technique to leak check the circuits before covering them with concrete.

Insulation under the slab is essential to keep the heat from radiating into the ground instead of into your garage. But where many contractors drop the ball is on the edges of the slab. The edges are responsible for high heat loss unless insulated.

In terms of expansion joints I dont know why someone would cut the joints with a saw instead of install the joints during the pour?? I used a very thin plastic joint material instead of the traditional thick fibrous material and the end result is nearly invisible and a creeper, jack or cherry picker will roll across the joint effortlessly.

As mentioned, the biggest downside, especially for an occasionally used work space, is turn around time. Heating a radiator as large as a concrete slab takes time! Keep in mind a forced air heater can be used to supplement the radiant floor heat, especially if opening and closing a large door, like an overhead door, will be occurring.

The great aspect of radiant floor heat is the fact the floor heats everything it comes in touch with. This means items which one will be actually touching, like metal tools, equipment, etc will be comfortable to touch instead of like grabbing ice cubes. With a blast heater used to quickly bring up ambient air temps the same items will lag behind and remain icy to the touch for a long time after comfortable ambient temps are realized.

Hope this helps, good luck!

  Tom Mooney

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I'll second the comments above.  Technically, heated floor is great - warmth is down where you are, rather that up at the ceiling.  I considered it when I built my pole barn a few years ago, but ultimately decided against it since I planned to only intermittently heat the space when I am working out there.  That big slab provides a lot of thermal inertia, so as JZRIV noted, the system works best when maintaining a constant temperature.  The other plus is that a standard hot water heater can be used as the 'furnace'.  Anyway, I wound-up just going with a hanging furnace that I could turn on and off.  When wrenching on your baby, it really doesn't need to be more than 50 degrees to be comfortable.  I installed electric baseboard in my enclosed 'office' area that I can keep warmer (60 ~ 65 F).

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 I have heat in the floor of my 40 X 60 pole barn and I am happy  I did it. You are only going to pour the floor once and I recommend the additional expense. I keep my building at 60 degrees and can work in short sleeves. After you are done washing anything in the garage the floor is dry in no time. There would be no moisture under your cars when being stored either. If you are planning on putting a lift in make sure you have an area marked out for the mounting hardware

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In May I will have 50 years in operating buildings of quite a few different sorts. My garage is 26 X 40 and I maintain the temperature at a minimum of 38 degrees in winter. I have a web based thermostat and either use my computer to raise it to work in or bring it up on my phone from the coffee shop to get it ready. The slab is a great heat sink and I flywheel through a lot of cold weather because of it. I prefer the warm air distribution. It feels good when the warm air comes on while working. And I have relocated the furnace three times due to changes in my working layout. Next year I hope to replace the existing furnace with a suspended horizontal unit to gain floor space, probably with AC. You can't add AC in the floor.

 

If you heat the building keep it heated. I am in a frozen wasteland a few months out of the year. Unheated, the ground under the slab and around the garage will all freeze. When the first warming comes in spring the ground will thaw and the area under the slab will be frozen. The ice will press outward to crack and raise the floor. Don't put a footer or key arch in if it is to go unheated in the future. I used a floating slab. It wiggles some and embedded pipes might not fare well.

 

I would be cautious about the pipes with the potential for the portable lifts available now. The weight might distribute OK, but there can be a risk. I have a scissors lift and planning to add a Max Jax and a Kwik Lift, all concentrate weight in unplanned locations.

 

If you do go with a heated floor consider PVC. You will need to go with a glycol mixture for the heating media for that situation when you don't have heat or power for some reason.  And you need to test and maintain the percentage of the mixture as well as treat it. That can be aggressive on some lead joint sealing materials and the caustic nature of concrete itself could be a problem in the future.

 

Above all, be sure the really seal the sill plate well, all the way around. That can be surprisingly windy when you lie on the floor!

 

My heat has cost about $300 per season for the last three years. Nothing in the garage has frozen and the contents are always above dewpoint, no condensation.

 

I am thinking about a 14X 26 addition with a taller ceiling. Things like that are easier with warm air distribution, too.

Bernie

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In May I will have 50 years in operating buildings of quite a few different sorts. My garage is 26 X 40 and I maintain the temperature at a minimum of 38 degrees in winter. I have a web based thermostat and either use my computer to raise it to work in or bring it up on my phone from the coffee shop to get it ready. The slab is a great heat sink and I flywheel through a lot of cold weather because of it. I prefer the warm air distribution. It feels good when the warm air comes on while working. And I have relocated the furnace three times due to changes in my working layout. Next year I hope to replace the existing furnace with a suspended horizontal unit to gain floor space, probably with AC. You can't add AC in the floor.

 

If you heat the building keep it heated. I am in a frozen wasteland a few months out of the year. Unheated, the ground under the slab and around the garage will all freeze. When the first warming comes in spring the ground will thaw and the area under the slab will be frozen. The ice will press outward to crack and raise the floor. Don't put a footer or key arch in if it is to go unheated in the future. I used a floating slab. It wiggles some and embedded pipes might not fare well.

 

I would be cautious about the pipes with the potential for the portable lifts available now. The weight might distribute OK, but there can be a risk. I have a scissors lift and planning to add a Max Jax and a Kwik Lift, all concentrate weight in unplanned locations.

 

If you do go with a heated floor consider PVC. You will need to go with a glycol mixture for the heating media for that situation when you don't have heat or power for some reason.  And you need to test and maintain the percentage of the mixture as well as treat it. That can be aggressive on some lead joint sealing materials and the caustic nature of concrete itself could be a problem in the future.

 

Above all, be sure the really seal the sill plate well, all the way around. That can be surprisingly windy when you lie on the floor!

 

My heat has cost about $300 per season for the last three years. Nothing in the garage has frozen and the contents are always above dewpoint, no condensation.

 

I am thinking about a 14X 26 addition with a taller ceiling. Things like that are easier with warm air distribution, too.

Bernie

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Have you checked out radiant tube heaters.  I have a well insulated 30 x 50 pole barn that I keep at 50 degrees (I'll bump it up a bit when I'm working on something ) during the winter and I love it. (12 years old, 40' long angled 45 degress so it heats across my shop)  It's very cheap to heat if you have natural gas and a lot easier to install.  And I have no moisture problems.  It doesn't run much at all since it heats objects,  floors, cars, etc...   which give off residual heat when it's off.  

 

Pros that I can think of.

Cheaper,   Quicker to heat,  lower electrical needs,  Easy to install in existing garages, No worry about leaks.

 

Cons

Louder but quieter than a hanging forced air blower,  Hotter when running closer to the burner,  Tube could rust out if it doesn't run long enough to burn moisture out at end of run.  (I solved this problem by using a thermostat that keeps it on until it raises 3 degrees from where it is set)

 

Here are a few pics.

IMG_0155.JPG

IMG_0355.JPG

IMG_0388.JPG

Edited by rapom
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