Replies

1. 
   user-2310254 | Feb 02, 2018 07:04pm | #1

   Will your local code allow you to encapsulate the asbestos tile? Does overlayering it with new material count as encapsulation?

2. GBA Editor
   Martin Holladay | Feb 03, 2018 06:08am | #2

   M Dubya,
   There are several issues here. In addition to the asbestos issue, there is the thermal performance issue.

   You should tell us your climate zone or geographical location. In general, it's a very bad idea to install in-floor heating over an uninsulated slab. You need a continuous horizontal layer of rigid foam above the slab -- at least an inch, but 2 or 3 inches would be better, depending on your climate zone -- before considering the installation of in-floor heat.

3. 
   Mdubya | Feb 04, 2018 02:18am | #3

   As far as I can tell, encapsulating the asbestos is permissible in Washington. I’m going to dig a little deeper and confirm prior to covering.

   Marine Zone 4.

   Slab is 4’ to 8’ below grade and stays a pretty consistent 50-55 degrees year round. Constrained by a couple of factors, main one is the floor comes to the bottom of a set of stairs and if I raise it 1”+, I will need to rework the entire set and second floor to stay within code limits. So trying to keep the buildup at a minimum on the floor.

4. GBA Editor
   Martin Holladay | Feb 04, 2018 06:36am | #4

   M Dubya,
   If your ceiling height permits, you might consider adding enough rigid foam to your floor to raise the finished floor by the height of one stair riser.

   If the ceiling height is an issue, your plan will work, as long as (a) you don't mind the energy penalty associated with heating an uninsulated floor, and (b) the installation instructions provided by the manufacturers of the cork underlayment, radiant floor mats, and vinyl flooring are consistent with your planned installation.

   I would gather up all these installation instructions (often available online) and read them carefully before proceeding.

5. 
   Mdubya | Feb 06, 2018 03:24pm | #5

   Thanks, Martin. I am constrained by ceiling height. I will research the instructions and get a better idea of energy efficiency before I proceed.

   Thanks again.