Reflective insulation

[bandmiller2]

Save the scraps of that thin foil insulation and make disposible insoles for inside your work boots.Frank C.

[SPIKER]

That PEX install looks good for the Mesh & stand offs, but looks like the PEX is too far apart for the northern climates. I'm told in Ohio you need 12" spacing, and 2 rows around perimeter 6" from outside walls.   This was told to me by guy who does the installs a lot.   
I got some info from a company who also has a 1/4" thick layer of foam built into the foil bubble stuff.   Unfortunately that is in my email which crashed and is all gone.. thank you YAHOO.

I bought the foil bubble bubble poly for under my slab, but I'm putting it between a layer of 1" white styro and /4" blue styro sandwich.  (plastic/poly vapor barrier, 1" white styro, foil side down bubble bubble poly, and then 3/4" pink/blue styro, mesh on chairs PEX-AL-PEX and then 5" concrete with fiber in 6000 mix.) this is what my floor is going to be made up of. I bought the PEX-AL-PEX and the fittings & the "Foil Bubble Bubble Poly" from Farmtek a year or two back. just prior to the prices all going up.   the pricing is all back down now, reason I didn't get it in was I still had to have the outdoor pipe run prior to doing the floor. time money and loss of job kept the pour from happening for a couple years almost now...   This other foil bubble foam stuff looks good I have a sample from "PRODEX" http://www.insulation4less.com that will be going into my boots for this next winter!  thanks for that IDEA! should be just enough if I cut the stuff just right...

Mark M

[moonhill]

I would place a caution on using the foil face bubble wrap as an insulator.  It needs an air space to work properly.  Squished under a slap leaves no air space, a vapor barrier, sure.  You can't beat 2" of foam under the slap, yes it cost more but you get what you pay for.  scsmith made a great point in his kiln being the same temp out side as in when the kiln is not running.  And being in the a warmer climate he will get away with it.  In the north it would be best to use the foam.   

I run pex on a 1' grid also and rebar for a floating slab.  After you get done with the pour the wire mesh is usually on the bottom of the slab not in the middle where it belongs. 

Tim

[OneWithWood]

For the pured floors of the greenhouses we used 2" styro underneath the slab and on the sides of the slab.  A lot of heat is lost out the slab sides if it is not insulated.  The pex was installed on 12" centers using two overlapping rows.  The greenhouse stays nice and toasty during the winter.

[Engineer]

I put a product under my basement slab that is thin foam on both sides with a layer of foil in between.  I put wire mesh on top of that, ran my tubing on 12" centers, and ziptied all the tubing to the wire, and then poured concrete.  My floor stays nice and warm, it actually heats my entire house except for two second-floor bathrooms.

[trimguy]

I found this old thread about Reflectix, I thought I would just add to it. This is the first hands-on experience I’ve had with it. These pictures are from the same wall in my shop from the same time.

 

  

That’s 20* difference. These readings were taken one afternoon. This wall gets sun all day. I realize that this will not make this much difference, if any on a wall that is shaded, but I would say it’s money we’ll spent. 

[Don P]

That is a good application for it. When I see it being used under a slab, don't do that with any notion of it being more than a vapor barrier. At best, till the bubbles pop, it is R-1 and provides no radiant benefit at all being in direct contact with the concrete. 

This is a good explanation;
Avoiding Home Energy Saving Scams – Part 2 - Reflective Insulation - Sustainable Energy Group

[trimguy]

Interesting, thanks Don.

[ljohnsaw]

I just bought the aluminum foil on Mylar product about 10 years ago.  I have a tile roof that was put on skip sheeting from the old shake roof.  There is a layer of Cool Roof or something like that to act as a tar paper.  Though it doesn't work that well I found out.  That's another story.  Anyhow, my 10/12 pitch roof gives a lot of attic space and it is HOT up there in the summer and pretty warm in the winter.  I stapled the Mylar product to the rafters and foil taped the seams.  I have a ridge vent, so air comes in the soffit vents and up the heat goes between the rafters now acting as plenums, and out the ridge vent.  It made a huge difference in my attic and more comfortable in the room below the attic - no heat radiating down.

[Raider Bill]

I stapled plain old aluminum foil to the underside of my roof decking in my garage.
Reflects the heat pretty good here in the hot south.
Dropped the underside of the roof 20 degrees

[peakbagger]

More than few independent building authorities do not give this type of insulation a good review 

Here is one 
Stay Away from Foil-Faced Bubble Wrap - GreenBuildingAdvisor 

[trimguy]

I wasn’t under the impression that I was getting any R value from this, I want something to reflect the excessive heat back out of my shop. My test convinced me that it was a big help. I put R-19 insulation inside of this to help with the temperature control.