Frequently Asked Questions

Who should install Thermalboard?

Thermalboard is typically installed by the general contractor with basic carpentry skills. A licensed radiant floor heating mechanical or plumbing contractor should install the heat source, distribution piping, pumps, controls etc.

Can all flooring goods be used over Thermalboard?

Yes. Consult the Thermalboard manual for the details regarding the application of flooring goods.

What kind of radiant tubing should I use?

One should use standard 3/8” barrier PEX tubing from any number of manufacturers. Do not use PEX-AL-Pex as it will become an oval when inserted in the grooves instead of rebounding to fill the slightly undercut grooves in Thermalboard. Standard PEX will expand into the groove creating a strong, silent connection enhancing thermal transfer.

Why is the tubing 8” apart?
Close spacing provides the best comfort. Tubing spaced further apart can create hot/cold spots, especially with low R-value finished floor goods. Closer spacing also provides better performance.
How much does it cost to install TB?
An inexperienced crew of two able carpenters can install an average of 150 sq. ft. per hour.
When is ThermalBoard installed?

ThermalBoard is typically installed just prior to the installation of finished flooring goods. Store ThermalBoard on the job site in a dry, cool space and it is ready to be installed with delays, in the natural progression of construction.

May I attach ThermalBoard directly to concrete?

ThermalBoard is specifically designed for attachment to a subfloor (plywood or OSB). When ThermalBoard is used over concrete, the installer must employ ome of the details on our manual in consultation with our tech support.

May I nail hardwood directly to ThermalBoard?
Yes, this is great advantage of ThermalBoard. You must use hardwood nails long enough to secure ThermalBoard to the sub floor (see the ThermalBoard Application/Installation manual).
Does Thermalboard outgas Formaldehyde?
Thermalboard does not outgas formaldehyde for two reasons. First, there is very little formaldehyde now used in MDF board, such as that used in Thermalboard. Secondly, Thermalboard is laminated with aluminum which does not permit the large formaldehyde molecules to pass. Here is an independent testing report on Thermalboard for formaldehyde outgassing which found zero levels measured. Download the full report here.
Should I attach something to TB before applying carpet?

We recommend a minimum 1/8” plywood or Masonite sheet be applied over ThermalBoard to avoid the remote possibility of extreme point load damage such as a piano or from sharp objects.

May I glue flooring goods to TB?

We now have a list for approved glues for some products. Consult with our tech support.

May I install a mortar bed over TB?
Yes. When installed with a slip-sheet or approved crack isolation membrane and proper reinforcement mesh, hard pack mortar may be applied over Thermalboard.
Will a tubing leak destroy ThermalBoard?

Leaks sometime occur during construction, primarily due too conflicting trades. The tubing can be lifted out of the groove at the leak , the groove routed to a larger size and a crimped or connected with a compression fitting. Thermalboard can usually be exposed to standing water for 24-36 hours before swelling occurs. After 36 hours Thermalboard may need to be replaced. Note that there are normally no tubing connections within Thermalboard, so it is extremely uncommon for PEX tubing to leak at any time during the life of the building. If you are concerned about plumbing leaks in the future that might affect the Thermalboard, we recommend using commonly available, inexpensive wireless water leak alarms at key locations around the building for general peace of mind. These water leak devices can alert your cell phone if a leak occurs.

How do I design manifold locations?
As you would normally. Tubing approaching a manifold location can be accommodated in custom grooves (with a standard 5/8” router) or covered with mortar.

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