Hello everyone. I just built a 60' x 50' garage that has two stories. I just installed radiant heat in the cement. I have the garage insulated very well (2 inches of insulation under cement, 2'' in walls and the attic is fully insulated. However, I am stuck on deciding on what type of ceiling to put in on the first floor. I don't want anything insulated as I want the heat to rise up to the second floor. Any suggestion?
Need help with ceiling choice in garage with radiant heat
- Thread starter jsottile
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Yellow Rose
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Assuming that the second story floor has the same dimensions as the ground floor - 60' x 50' - you can put no first floor ceiling in and you will still be at your dilemma.
There are three modes of heat transfer. In order of greatest to least motive force they are conductive, radiant and convective. Conductive is actually touching a cooler surface to the warmer surface. Radiant is such as the heating elements in your concrete floor. Convective is the gentle flow of air from the warmer area to the cooler area. This is the "warm air rises" concept.
In your situation radiant heat emanating from the warm concrete morphs into convective heat transfer that warms the bottom story. However, once the warm air rises to the bottom of the second floor, it has consumed all of its motive energy to transfer a substantial amount of heat through the second story floor, such that the second story air space is warmed. Said another way, warm air rises, but it cannot penetrate solid objects like the first story ceiling - insulated or not.
There are three modes of heat transfer. In order of greatest to least motive force they are conductive, radiant and convective. Conductive is actually touching a cooler surface to the warmer surface. Radiant is such as the heating elements in your concrete floor. Convective is the gentle flow of air from the warmer area to the cooler area. This is the "warm air rises" concept.
In your situation radiant heat emanating from the warm concrete morphs into convective heat transfer that warms the bottom story. However, once the warm air rises to the bottom of the second floor, it has consumed all of its motive energy to transfer a substantial amount of heat through the second story floor, such that the second story air space is warmed. Said another way, warm air rises, but it cannot penetrate solid objects like the first story ceiling - insulated or not.
Hello Andy,
Thanks for the post. So you are saying that no matter what I do I will not have effective heat transfer to the second floor? I have 9 foot ceilings on the first floor. I don't use the second floor all that much and this past winter the heat from the first floor did warm the second floor to an extent. The reason I want a ceiling on the first floor is because I am loosing too much light into the ceiling. Also, I don't have a solid subfloor on the second story and a lot of debris is falling inbetween the cracks of the second story wooden floor (which ends up on my vehicles). I have even considered using peg board (painting it white to reflect the light down) and using that weed blocker paper on the reverse side as it will not trap moisture and will prevent debris from going through the pegboard. Worst case scenario I could add additional zones to the boiler and run the radiant heat under the second floor. However, this would be very time consuming running all the loops under the floor.
Any suggestions??
Thanks for the post. So you are saying that no matter what I do I will not have effective heat transfer to the second floor? I have 9 foot ceilings on the first floor. I don't use the second floor all that much and this past winter the heat from the first floor did warm the second floor to an extent. The reason I want a ceiling on the first floor is because I am loosing too much light into the ceiling. Also, I don't have a solid subfloor on the second story and a lot of debris is falling inbetween the cracks of the second story wooden floor (which ends up on my vehicles). I have even considered using peg board (painting it white to reflect the light down) and using that weed blocker paper on the reverse side as it will not trap moisture and will prevent debris from going through the pegboard. Worst case scenario I could add additional zones to the boiler and run the radiant heat under the second floor. However, this would be very time consuming running all the loops under the floor.
Any suggestions??
Yellow Rose
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You will get a some heat transfer into the air space of the second story; however, intuitively it will not be enough to warm that air space as much as the downstairs air.
Perhaps the 2' x 2' or 2' x 4' tiles you see on an office building's ceiling is your best choice. It is only 1/2" thick, so whatever its R-rating is, there will not be that much heat blockage.
Perhaps the 2' x 2' or 2' x 4' tiles you see on an office building's ceiling is your best choice. It is only 1/2" thick, so whatever its R-rating is, there will not be that much heat blockage.
If you are just interested in preventing falling debris, you could just staple up plastic sheeting. Also in very hot climates they have an aluminum foil product that they put on the bottom of the roof rafters to reflect the radiant heat and keep it out of the attic. It would be non-flammable, light reflective and would conduct heat.
FYI: http://www.sunshineforecast.com/products.htm
FYI: http://www.sunshineforecast.com/products.htm
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