With radiant heat, the heat source is directly beneath the flooring.   Wood flooring can be installed over radiant heat as long as you understand radiant heating systems and how they can impact wood flooring, what precautions to take, and what type of wood flooring to use.   One of the most important considerations when installing a wood floor over radiant heat is it’s dimensionally stability.   You want a wood flooring product that will not expand and contract excessively.   Because of it’s dimensionally stability, Engineered Wood Flooring is an ideal choice for this type of application since it significantly more stable than a solid wood floor in both width and length.   This being said, there are still specific guidelines that must be met before, during and after installation to insure the proper performance of your flooring and to maintain your warranty.  Failure to follow there procedures and guidelines can void the warranties for your flooring.

GENERAL RADIANT HEAT INSTALLATION GUIDELINES

Rapid changes in temperature can cause large fluctuations in the moisture content of wood flooring which can damage the wood and its finish. To minimize the effect that these rapid changes in temperature will have on the moisture content of the wood floor, it is highly recommended that an outside thermostat be installed in addition to a standard interior thermostat. lf one is not present, we recommend that one be considered. Unlike conventional heating systems where the heat is typically switched on or off only after significant changes occur outside (which causes a rapid temperature increase or decrease, radiant heating systems work most effectively, and with less trauma to the wood floor, if the heating process is gradual and based on small incremental increases in relation to the outside temperature. In addition, to avoid damage to the flooring, due to excessive drying, the radiant heating system MUST be regulated not to exceed 850F. If it is not and the system exceeds 850F, it can damage the flooring and void the warranty.

As with all installations, the subfloor should have proper moisture tests performed prior to the start of installation to insure that it falls within the required range of less than 14%. In addition, be certain that the job site is weather tight and there isn’t an opportunity for moisture to enter. 

In most cases radiant heat systems have tubes or wires that should not be penetrated by nails or other fasteners.   Therefore, the essential requirement in properly installed wood floor over radiant heat systems is to avoid penetration of the heating elements (check with the radiant heat system supplier for exact requirements). In addition, with a water or liquid-based radiant heating systems, a pressure test should be performed, by a qualified plumber or the system installer, to insure there are no leaks, PRIOR to beginning the installation of the wood flooring.

Radiant heated subfloor systems can be concrete, wood or a combination of both. The type of subfloor determines the subfloor preparation.   Be certain that the radiant heating system is installed following the manufacturer’s installation procedures exactly. 

If the subfloor is concrete and it has cured, turn the heat on, regardless of season, and leave it on for at least 5-6 days before installation of the wood flooring to drive out residual moisture. However, the system must be turned off entirely for a minimum of 24 hours priors to starting the flooring installation and must NOT be turned on for 24 hours AFTER the installation is complete. This is true regardless of the subfloor type.

After the system has been off for a minimum of 24 hours, install the flooring as described in the installation instructions for the installation method you have chosen (i.e., Glue-Down, Nail/Staple-Down or Floating). If you are installing over a concrete slab with the radiant heat system imbedded in the concrete you can glue the flooring down directly to the slab or float it. If you are using a radiant heat system installed above a concrete slab or wood subfloor you will typically need to add sleepers between the radiant system and then an additional layer of ¾ ” thick plywood over them before installing the floor.  

NOTE: Again, if you are using a nail or staple down installation method, be certain that you do not damage the radiant system with the fasteners.