How to Install Radiant Heating Over Pre-Existing Concrete

Radiant heat warms a floor's surface through electric mats or water tubing installed on the surface of a concrete floor and encased in an additional thin layer of concrete or thinset. The heat from the radiant heated floor rises to heat all surfaces in a room or home. This system does not move the air with blowers and thereby reduces dust and allergens. Radiant heating systems are cost-effective; it pays to research the lowest energy source before deciding the type of radiant heat to install.

Things You'll Need

  • Tape measure

  • Layout sheet

  • Radiant matting

  • Continuity tester

  • Ground-fault circuit interrupter

  • Electrician

  • Thermostat

  • Trowel

  • Thinset

  • Water tubing

  • Concrete fasteners

Electric Radiant Heat

Step 1

Fax or email a layout of the room or area of the planned installation to the electric matting manufacturer. Measure carefully and mark any permanent fixtures such as cabinets or plumbing fixtures on the diagram. The manufacturer will ship the correct amount of matting to you with trimming instructions for an exact fit to the installation area.

Step 2

Consult an electrician concerning the installation of an additional dedicated circuit for the radiant heat. Protect the circuit supplying electricity to the radiant heat with a ground-fault circuit interrupter and a properly installed thermostat.

Step 3

Trim the matting carefully, do not cut any of the electric cabling attached to the mesh. Lay the matting out in the installation area. Test the cabling with a continuity tester to ensure there are not breaks in the cabling.

Step 4

Staple the matting to the floor to hold it in place, if necessary. Test the continuity of the cabling again. Apply a layer of thinset completely covering the radiant heating mesh. Allow drying of the thinset for the recommended time on the thinset packaging.

Step 5

Connect the matting to the electrical source and the thermostat. Install the floor covering of choice. Note: If installing ceramic tile, an additional layer of thinset will be required to set the tiles.

Hydronic Radiant Heat

Step 1

Lay the water tubing on the concrete floor in a continuous back and forth manner. Make any turns rounded, avoiding sharp turns that can kink the tubing. Hold the tubing in place with fasteners driven into the concrete. Use care not to nick the tubing.

Step 2

Apply a layer of thinset or lightweight gypsum to cover the water tubing. Use a trowel to create a smooth continuous coating. Allow this coating to dry completely.

Step 3

Attach the tubing to the hot water source and the inline pump that will circulate the hot water through the tubing. The hot water flows through the tubing, warming the floor and then returns to its source to be re-circulated again.


Hydronic radiant heat is generally more expensive to install than electric, but you have a range of choices for the energy source to heat the water.

References & Resources