Radiant Heat Insulation

NewHouse2016

I am in the process of having a new house built that has radiant heat in the basement slab and stapled up to the first and second floor sub floors. My builder had initially insulated the first floor/basement ceiling between the floor joists with kraft faced insulation with the paper exposed towards the basement. The building inspector told him that did not meet code because of the fire hazard of the exposed paper, three quarters of the basement does not have a finished ceiling. My contractor then reinstalled the insulation with the with the paper towards the sub floor which leaves exposed insulation towards the basement. I expressed concern of having 2000 sq ft of insulation that was not covered with anything in a space that will be occupied for some portion of the time by my family. The contractors solution is to cover the insulation with an aluminum faced paper that is perforated with tiny holes and meets fire code. Where there is no piping, wiring etc the installation of this material will be fairly straight forward and have a clean appearance, where there is piping etc it will not be easy to install.

My questions are 1) would it hurt to install aluminum faced insulation over the already installed kraft faced insulation that has the paper towards the radiant heat tubes? The aluminum facing of the new insulation would face towards the basement. The aluminum paper they were going to install has tiny holes whereas the aluminum faced insulation doesn't have holes. Does the lack of holes create any issues from a vapor barrier perspective in this application? The basement will be heated 60 to 65 Fahrenheit. 2) are there any concerns with having the paper of the existing kraft faced insulation in close proximity to the radiant heat tubes?

Any help would be greatly appreciated.

Zman

You are correct to be concerned.

As for kraft insulation. It is a home owner/home depot product. It is not tight enough to be a true air barrier but might trap some moisture here and there. It should not be in your house at all. I would never put it with kraft against the tubing as it may really smell when the heat comes on. A perforated product with a low flame spread rating would be appropriate for the bottom side.

I would have the contractor bring the Kraft product back to home depot and have them replace in with unfaced. They can then install the aluminum perforated product on the bottom.

Paul Pollets

Was the radiant tubing within the floor joists installed with aluminum transfer plates?