Where the insulation

Jeffrey Campbell

Jeffrey Campbell

Wheres the insulation

I have a customer who called me up to look at his home. The home is ready for rough-in. The floor heating will use metal decking with 4" of concrete> I went into my insulation speal. He demands that the underside of the metal decking be exposed. I expalined to him the importance of underside insulation, and he is not willing to use it. One good thing, there are no floor covering they are leaving the concrete exposed. He is installing radiant with or with me. What should I do. I have in the past done a home with out underside insulation and it worked well, but now understanding more aobut the whole design it goes against all we are taught?
Thanks Jeffrey

Constantin

Sounds like a controls problem...

From your description, some rooms might feature radiant floor and ceiling emitters if zones on two floors are calling for heat simultaneously. Thus, some rooms on the underside may overheat, while top-floor rooms may take a long time to warm...

I wonder how much heat will escape down instead of up in these kinds of circumstances. Is there a finished ceiling underneath the metal deck or do the owners want it exposed? Such a ceiling might provide the insulation you need to squeeze most of the BTUs up.

Matt_21

why don't you

install a 1" styrofoam board on the decking, attach the tubing and pour your concrete. you could also install insultarp. i haven't used it but it looks to be thinner than a 1" styrofoam board. definately try to get some insul in the floor or you will probably have temp issues like constantin mentioned

Unknown

one of the few cases where I'd say if you can't get the foam board in on top of the decking, try the insultarp. At least you'll get some kind of thermal break and with no floor covering above, it should be ok.

just make sure you zone the lower floor adequately, it will be picking up some heat gain.

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Unknown

I feel your pain!

Jeff,

Same problem here. HUGE custom built, full home suspended concrete floors on steel decking. NO WAY will the engineer allow insulation below or even in the slab.

So, I simply am giving him what the enginner and architect and homwowner have asked for. I asked for a BTU upward output figure and he gave it to me :-)

Now it is a simple selection to install slab sensors on all slabs and go from there.

My bet is there will be spray foam insulation in 2 years!

Jeffrey Campbell

I am meeting with the Owners

and Contractor tomorrow. Hopefully I can talk them into insultrap or foil bubble under the slab. I appreciate the feedback.
Thanks Jeffrey