Installing Pex Tubing for Concrete Slab Underfloor Heating

Installing Pex tubing for concrete slab underfloor heating is one of the easiest ways to install radiant heat. When installed in a concrete slab, radiant underfloor heating is very efficient and comfortable. Since the concrete slab installation is fairly simple, many people fail to follow some simple yet very important steps thinking that it will work no matter what. To make sure you do the work right, please read this manual.

When you buy the tubing from Radiantec, we’ll provide you with a custom tubing layout. This layout is part of our free design assistance and many of our customers find it very helpful. Since concrete is a decent conductor of heat, having an exact and perfect tubing arrangement isn’t necessary for most projects. You should try to use all of the tubing that was specified, space it out reasonably well, and make sure the tubing lengths are neither too short or too long. In areas with a lot of windows, the tubing can be spaced closer. In the middle of the room or in closets, space it further apart.

General Rules of Thumb for Concrete Slab Underfloor Heating Installations

These recommendations are general in nature. As with any building project, be certain to check with your code official before starting the work.

  1. On top of the compacted earth or sand, install a vapor barrier.
  2. Lay down at least 2″ of rigid foam insulation. Extruded or expanded polystyrene is the material of choice. Radiantec doesn’t recommend using radiant barriers or “bubble wrap” insulation for radiant floor heating.
  3. Install the wire mesh or rebar for the concrete slab.
  4. Attach the tubing to the wire mesh or rebar using plastic zip ties. If there is no steel, it is acceptable to staple the tubing directly to the insulation.
  5. Connect the tubing to a Radiantec slab manifold and pressure test.

Be sure to also read our Design and Construction Manual and to give us a call with any questions. We’re here to help make sure your underfloor heating project is installed correctly and will provide many years of trouble-free operation.


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