Under slab insulation

Bill_95

Can someone tell me if the 2" ridgid board is still the best proven product to use under a large(10,000)sq ft shop floor to be heated with radiant infloor? Is it necessary to us a vapor barrier if the water table is not a problem? There is so much talk about the roll products but no actual ASTM tests. What is the best? Thanks Bill

Bill_95

Under Slab insulation Radiant Floor

Is it necessary to insulate the entire slab. The slab footprint is 125'x 80'. I have been told the first 10' around the perimeter is sufficient. Is this correct?

Unknown

yes, yes, yes and more!

Yes the 2" is the best with vapor sheeting below it... Make sure the gravel is COMPACTED !!!! Another best way is to insulate the foundation walls too ! Some will say 2 " is wasted in the middle but how much cost differnrce? I always 2" all rounds and walls too.... Stay away form the bubble sheet craps...

kevin coppinger_4

ditto...

dow eps is the standard...bubble foil is snake oil...yes there is test results info...ceck out Robert Beans website... www.healthyheating.com


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Justin Gavin_5

Don't Skimp

I agree fully with what the other fellas have stated. If you are gong to to put a radiant system and you want it to heat efficiently (even if you are using a woodstove) you have to insulate. Bubble wrap is crap as an underslap insulator in my opinion and at best a very expensive vapor barrier. It simply doesn't have the mass.

Also look at the labor of stapling down the foam vs. zip ties. You will save time, money, and your back.

Remember with Radiant Slab installs you don't get second chances. You wouldn't skimp on you attic or wall insulation would you?

The most important factor is that you have to treat the building as a system.

The thermal envelope is just as critical if not more critical than the tubing, heat source, and ventilation because all of you factors are based on the integrity of your buildings construction.

Good Luck,

Justin

Rich Kontny_3

Insultarp

I have used "Insultarp" in the past and have had excellent results. This is much more than "bubble wrap" and is comparable to 2" styrofoam with it's four different layers.

It also acts as a vapor barrier, is much faster than styrofoam, does not crack and has a reflective surface. I can't find the info but they have done case studies where "Insultarp" out performs 2" styrofoam.

Take the time to research this as all manufacturers make claims without any backup. Insultarp does have testimonials and case studies if you request them!

Rich K.