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radiant floor heating Post New Topic | Post Reply
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Matt Kenner
Posted: Dec 14, 2009 10:22 AM
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radiant floor heating
A customer is having radiant floor heating installed on the crawl space ceiling. He wants spf applied after the radiant is installed. Would I have to cover the pipes with some rigid foam before applying spf (leaving a 1-2" air gap)? How would you handle this scenario? This is my first time dealing with a radiant floor heating system.
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mason
Posted: Dec 14, 2009 11:22 AM
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The SPFA just concluded a year long study on the use of sprayfoam over cPVC pipe and concluded that either open or closed cell foam poses no problems when sprayed directly onto the pipe. However I would spray the foam in 1/2 inch lift on the pipe first, then let it set for a few minutes to let the heat dissipate. Then you should be able to bring it up to the thickness desired without affecting the pipe. |
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mason
Posted: Dec 14, 2009 11:29 AM
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By the way, so long as the pipes do not exceed 200 degrees in temperature, the foam should be OK. If the pipes exceeded that temperature you would want to stay off the pipes at least 3 inches. |
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Matt Kenner
Posted: Dec 14, 2009 11:35 AM
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Thanks Mason. |
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Grady Littlehale
Posted: Dec 14, 2009 04:56 PM
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I use 1.5" board stock cut to joist width and 1.5" cc to seal it with. I did leave a 2" airspace that you need with radiant heat. Works great. |
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Circle-D
Posted: Dec 14, 2009 10:08 PM
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Mason, If you don't cover the it with something, won't the foam expand completely around the tubing and insulate it FROM the floor your trying to heat? Just my thoughts....Skip |
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mason
Posted: Dec 15, 2009 08:37 AM
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Circle D, good point. I like the idea of using board stock over the pipes then insulate with foam. |
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Matt Kenner
Posted: Dec 15, 2009 10:33 AM
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I did some searching on radiant floor systems installed in crawl spaces (between floor joists) and they have "u-shaped" metal plates with flanges for attaching to the crawl space ceiling. I would think we could use these plates and spray directly over them as long as we seal where the plates butt up to one another (similar to link below) www.radiantcompany.com/details/joists.shtml |
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Lane Hogstad
Posted: Dec 15, 2009 02:19 PM
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Mason, Were you talking about pex or cpvc? |
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Posted: Dec 15, 2009 06:17 PM
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do not spray directly to the tubeing,,, you will have really well insulated tubeing,,and a radiant system that does not work... you need an airspace/plenum with the tubeing in it,,,a seperating media,,then the spray foam...anything will work for the media...filterglass,,,boardstock of one sort or the other,,,reflexive foil/board,,,the ductboard stuff the hvac guys use for coldair returns (the name escapes me,,anything that can be fastened well enough to allow the high pressure spray application of the foam....i prefer to use oc for this application....the more the better..lol get the heat goin where it needs to,,,up... |
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Grady Littlehale
Posted: Dec 15, 2009 07:02 PM
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Try the foil faced cardboard from insulationsolutions.com. I got a bunch but havent used them yet,Going to spray oc to them. |
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mason
Posted: Dec 16, 2009 01:06 PM
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I appreciate the good information provided on this topic. As many of you picked up on this particular thread, I initially was thinking only of the capatability of the foam with the piping and not the fact that radiant heating must have an open space around the pipes to produce the desired results. Thanks, guys for being on the ball. |
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John Shockney
Posted: Dec 28, 2009 01:04 PM
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We use the 16inch wide aluminum foil bubble wrap it is a friction fit into the joise space and is ez to install, Then spray directly over it with open cell foam |
