Radiant Heat and insulation type

[Flexia]

I am planning to do radiant heat in by building thats going up this year. What would be the best insulation type. XPS or EPS? I have heard both and also what PSI do I want to have with a 4in slab on it? Also would r17 be overkill for the slab? Local to me there is a Clist add selling 3.4in xps 30psi sheets that are 4x12 for like $50. Is this a deal I shouldn't pass up?

 

[rburke65]

Well for starters, it would help us to help you if we knew where in the world you are located.

 

[Flexia]

Well for starters, it would help us to help you if we knew where in the world you are located.

Yeah that may help. In actually in akron/canton ohio. not to far from you it looks like

 

[TheEquineFencer]

take a look at my posting at this link.

http://www.garagejournal.com/forum/showthread.php?p=3120180&posted=1#post3120180

 

[BadgerBoilerMN]

We use 25psi for commercial buildings with heavy traffic.

 

[Highbeam]

You can use either XPS or EPS, I used and like the idea of 25 psi. Save lots of money by using EPS and underslab is an approved installation of the EPS per the manufacturer. I have never seen a true reason to use XPS instead? Lots of rumors and old wive's tales though.

 

[BadgerBoilerMN]

I think this is true, though I can't find a bargain EPS price in the area. I just got a sample of a new retrofit radiant panel with aluminum face at 90psi...quite impressive!

 

[OldNeons]

Could someone please explain the minimum insulation requirements for under slab insulation, both for a radiant in floor heat system and just as a good under slab conduction barrier in a garage to be maintained about 45 in winters. If EPS works, it's much cheaper.....

 

[Highbeam]

Could someone please explain the minimum insulation requirements for under slab insulation, both for a radiant in floor heat system and just as a good under slab conduction barrier in a garage to be maintained about 45 in winters. If EPS works, it's much cheaper.....

Of course EPS works.

All insulation has R-value per inch. The amount of insulation you install is directly related to heating costs. Code minimum in a living space is R-10 as I recall which is 2" of foam. It is not required in your garage.

In the abscence of better information about your application, the standard is 2" foam all around the slab. Only leave the top exposed to the garage area.