Question

I want to install bamboo flooring over a concrete slab, with electric radiant heating between. Can you give me advice?

Asked by Estelle Lampley
Mechanicsburg, PA

Can I do this myself?

Answer

Cynthia Phakos

Answered by Cynthia Phakos

Los Angeles, CA

Koffka Phakos Design

November 14, 2011

Installing a radiant floor system on concrete with a wood floor finish is a complicated issue and not the best do-it-yourself project.

An improper installation will jeopardize the performance of system and as this is a costly endeavor you want to have it done correctly.

Bamboo also presents a number of issues when paired with a radiant floor system. Start by looking at Lily Marie Livingston's informative answer to the question "We are considering radiant heat. Will manufactured bamboo flooring stand up to the challenge?"  She discusses what to look for in selecting the bamboo for a radiant floor installation and how you can find a reputable installer.

Choose a floating floor system rather than glue down

A floating floor system is recommended as it allows for movement as the wood expands and contracts with temperature change. The glue down flooring that you are considering is not the best choice over a radiant heating system.

  • When installing the floor boards one typically starts at one end of the room, leaving a gap at the other end for expansion and contraction. The gap can then be hidden with a baseboard, which should be nailed to the wall and not the floor. Some of the systems are self locking.
  • Check with the manufacturer of the Bamboo flooring as to whether the material is warrantied for use with an electric radiant heating system.
  • Teragren manufactures quality bamboo flooring that is suitable for a radiant electric heat system. Their adhesives have passed the most stringent air quality standard in the world, qualifying them to earn LEED® v3 credit IEQ 4.3: Low-Emitting Materials—Flooring Systems. More details here.

The concrete slab

Next to consider is the installation over the concrete slab. Molly McCabe's answer to a question here on GreenHomeGuide enumerated the steps below.

  • Given that your slab is 30 years old, inspect the slab for any cracking as this could telescope through causing issues with your finished floor.
  • You should seal the concrete slab. Moisture migrating up through the slab can cause the wood floor to cup.
  • Next install a thermal barrier which will isolate the slab from the heating elements so that the slab does not act as a heat sink. The heat will then be directed up into the room where you want it. An insulated cement board typical used for tile installations will serve this purpose.
  • ProPanel has a lightweight waterproof backer board (described here) made up of a high-density polystyrene core faced with a fiberglass reinforcement and coated with a polymer cement waterproofing. It comes in various thicknesses (as thin as a ¼” thick panel if height is an issue). You can either glue the panel with an adhesive to the concrete or thinset it (similar to a tile installation) with mortar to the slab. I would recommend the latter method as adhesives can be high in VOC content.

The electric radiant system

In selecting, installing and using a radiant electric system there are some things to keep in mind.

  • The heating elements should be installed perpendicular to the direction the flooring for ease of installation for the flooring relative to the heating elements. The elements which are approximately 3/64” thick and can be thinset to the cement board, spaced as recommended.
  • The maximum temperature must be less than 85 degrees Fahrenheit so that it will not damage the bamboo. Residential systems are typically 82 degrees per lineal ft. and 7.8 watts.
  • When operating the system allow it to heat the floor slowly, so as not to stress the wood.
  • The systems are self-regulating with elements acting dependent on the specific conditions. They will sense if there is sunlight on the floor or and area rug and adjust accordingly to minimize excessive heat in the flooring.
  • The manufacturer’s Tech Support are very helpful in answering specific questions on the system.

Tagged In: bamboo flooring, radiant heat

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