How To Install Radiant Heat Flooring

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Does your floor give you cold feet? Radiant heat flooring is just the thing to make your cold floors comfortably warm. For use as both primary and supplemental heating systems, radiant floor heating can be installed during home construction but is commonly added to existing floors with moderate ease and just a few tools. In this article we’ll discuss how to install radiant heat flooring in two different ways to cover 100 square feet of an existing floor.

Types of Radiant Heat Flooring

There are two types of radiant heat flooring. Those are hydronic (hot water) systems and electric systems. Within those two types, there are several methods of installation. Below you’ll find installation instructions for the easiest ways to retrofit both kinds into an existing floor. Both are cost-effective ways to make your floors more comfortable and inviting.

When to Install Radiant Heat Flooring

Retrofitting radiant heat into existing floors is common, especially during remodeling. If you have the opportunity, the best time to install radiant heat is before the construction of a home or new addition is complete. However, installing radiant heat flooring can be done anytime following these guidelines.

Safety Considerations

Standard safety precautions are the rule when using power tools. Choosing to install electrical in-floor heating will require working with 110V electrical wiring. Follow all electrical safety procedures.

Hydronic floor heating systems require plumbing connections to your boiler or water heater. Making these connections is possible for a well-qualified DIYer, but it’s better left to the pros for most homeowners.


Hydronic Radiant Floor Heat Tools

Hydronic Radiant Floor Heat Materials

How To Install Radiant Heat Flooring

Electric Radiant Floor Heat Tools

Electric Radiant Floor Heat Materials

Hydronic Radiant Flooring Installation Instructions

The following method requires access to the joist spaces below the floor that’s to be heated. It’s best for homes with unfinished basements. You can remove ceiling drywall for access, but replacing it can be difficult or expensive.

1.Layout Pattern

From underneath the floor, in the basement, mark a layout on the ceiling with a marker. Make marks at six- to eight-inch increments where the heat tubing will be placed. Also mark locations where the tubing will pass through the floor joists.

2.Drill Holes

Drill 7/8 inch holes in the joists where the tubing will pass through. Be sure to follow local building codes regarding the quantity and location of the holes. Skip this step if you have truss-type floor joists common in newer construction.

3.Install PEX Tubing

One section at a time, insert the PEX tubing into the aluminum heat transfer plates. Secure them to the underside of the floor with heavy-duty staples following your marked pattern. As you go, pass the PEX tubing through the previously drilled holes. Leave about two feet of extra tubing on both ends for making hot water connections later.

4.Install Insulation

Friction fit and staple the insulation batts in place with the faced side toward you. Leave the extra two feet of heat tubing exposed.

5.Connect Plumbing to Heat Source

Make the plumbing connections to your boiler system or a dedicated water heater. This is a good time to call in a professional if you’re not familiar with hot-water heating loops.

Electric Radiant Flooring Installation Instructions

This method works best for homes where there is little or no access to the space below the floor. For the best results, any existing floor will need to be removed down to the subfloor.

1.Prepare Workspace

Remove the existing floor covering down to the subfloor and sweep clean.

2.Lay Out Electric Heating Mats or Cables

Lay out the electric heating mats or cables to cover as much of the floor space as desired. Don’t overlap any part of the mats. Staple or adhere the mats or cables to the subfloor according to the manufacturer’s instructions.

Place the thermocouple provided with the mats at least 12 inches from any walls and as close to the center of the floor as possible.

Gather the wires from the thermocouple and from each mat. Run them along the wall to where the electrical connections will be made. Isolate three feet of each wire by taping them to the wall above the floor. This will be important for the next step.

3.Level the Floor

Following instructions located on the bag, mix and pour the floor leveling compound evenly over the entire floor. Keep adding to reach a thickness of ¼ inch or until the mats or cables are fully submerged. Allow the compound to cure undisturbed for 24 to 72 hours.

4.Connect Electricity

Connect the wires from all the mats to the house’s electrical circuitry following electrical building codes. Connect the thermocouple wire to the thermostat following the included wiring directions. This is a good time to call in a professional if you are unfamiliar with electrical wiring procedures.

5.Install New Floor

Your floor is now ready for its new covering. Tile, laminate, vinyl, linoleum, even carpet with a dense pad are all good options. Coverings can be installed directly on top of the leveling compound once it’s cured. Avoid penetrating the new subfloor with tack strips or other fasteners to keep from damaging the electrical components.


Electric radiant heating cables and mats can also be installed in the joist spaces below the subfloor. Staple the cables or mats to the underside of the floor and wire as normal. Follow the guidelines above to insulate the joist spaces.

When to Call a Pro

Doing most of the work yourself will cut your radiant floor heat costs by about half. But most homeowners elect to hire a professional to connect new hydronic heating to the existing hot water source. Connecting electric floor heat components to existing wiring is a straightforward process if you’re experienced with wiring techniques. If not, hire an electrician to make the final connections.

In older homes, be mindful of the possible existence of asbestos in old flooring materials. If asbestos is suspected, call a professional to test and remove the flooring if necessary.

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