Best insulation for staple up radiant floor

[headrc]

After receiving feedback on the idea of a conditioned crawlspace for radiant heat ...(thx!) ....I now wonder what is the best form of insulation put under staple up radiant heat (between floor joists ) ....any input would be appreciated.

Thx, RH

[21degrees]

[QUOTE=headrc;1896427]


you should ask your contractor or would that be yu!

[nevea2be]

After receiving feedback on the idea of a conditioned crawlspace for radiant heat ...(thx!) ....I now wonder what is the best form of insulation put under staple up radiant heat (between floor joists ) ....any input would be appreciated.

Thx, RH

If your crawlspace is closed up just like a cellar then this is what I did; I used preformed aluminum plates to cover and secure the tubing to the floor between the joist's. They recommend placing about 10 inches apart to install more plates if more heat is needed in that area. I figured using plates all the way down the tubing spaced an inch or so apart for expansion and contraction would just give you the maximum heat output for your money. In stead of using a reflective foil an inch below the tubing (to heat the air) I instead used 1/2 inch reflective form board the fit snugly between the joist's. Yes it's a little more money but after looking at the different types of foils out there the foam board just made more sense since it didn't allow any heat to escape below to the area where I didn't wish to heat, plus it has an R-value of 3.3 and an R-value of 6.1 with 3/4 inch of air space. Below that I just used R-19 unfaced insulation.

http://www.radiantec.com/pdf/Within_...diant_Heat.pdf

[beenthere]

The 1" gap between plates doesn't give you more heat. Could lower it some.
The 10" gap allows better convection in teh cavity.

[nevea2be]

The 1" gap between plates doesn't give you more heat. Could lower it some.
The 10" gap allows better convection in teh cavity.

I've never seen anyone recommend a 10" space between the tubing and the reflective material before, 1/2 inch to maybe a 1 1/2 or 2" yes but never a 10" gap.

[beenthere]

I've never seen anyone recommend a 10" space between the tubing and the reflective material before, 1/2 inch to maybe a 1 1/2 or 2" yes but never a 10" gap.

Maybe you should read the PDF you posted.

[nevea2be]

Maybe you should read the PDF you posted.

I did and it doesn't say anything about a 10" gap allowing better convection in the cavity. The only mention of 10" is the 8-10" for the spacing of the aluminium plates which I mentioned in my first post.

[mcaylor]

nevea2be is talking about the space between the ends of each aluminum plate, not the space between the plates and the foil insulation material. Less space between plates means more aluminum to cover area which should increase heat transfer.

[snupytcb]

if you are using plates i dont think you need reflective insulation, most people i believe just use batted.

[nevea2be]

if you are using plates i dont think you need reflective insulation, most people i believe just use batted.

The plates just allow more of a surface area to be heated in the floor in a quicker time frame. The reflective material is what forces the heat to reflect up to the floor. By using just insulation the fiberglass would absorb some of the heat rather then putting it in the floor where you want it to go. Think of it as no matter how cool your house is if you go up inside a hot attic and feel the insulation, it's going to be warm or hot to the touch. Insulation absorbs the temperature it's in, much like any other material.

[beenthere]

I never put those thin plates against the floor. If you leave a space between the plates and floor, you leave more spave between the plates to take advantage of the convection.