How to Pour Concrete Floor Radiant Heat

Radiant flooring tubes
  • 5-20 hours
  • Intermediate
  • 0-10,000
What You'll Need
Concrete mixture
Reinforcing fiber
Radiant heat flooring

Radiant heating is becoming a very popular method of heating private homes, and using a concrete floor radiant heat system can both save you money, and help reduce the amount of greenhouse gases your home produces. The most common form of under-floor heating consists of a layer of tubing, and concrete poured across the top of these elements. In order to properly lay a concrete floor radiant heat system, you will need to know how to make sure the concrete is the right consistency to support a heating device. Follow a few simple guidelines to get the best out of your concrete floor radiant heat unit.

Step 1 - Prepare the Floor

Before you begin making your concrete, you should ensure that the floor is correctly arranged so that your new radiant heat system will work to the best of its powers. The floor should be ready, with the tubes laid, and a good layer of insulation covered with boards below this. Insulation is vital in preventing your heat from moving in the wrong direction, and heating anything below the under-floor tubes.

Make sure the insulation and flooring is all sealed, perhaps by laying a sheet of plastic. You should also remember that anything in direct contact with your new pour will take the heat away from your flooring. You can also conceal the insulation by using foam board, and trimming it so that concrete flows all the way across the insulation, hiding it.

Step 2 - Mix the Concrete

mixing concrete in a bucket

When making concrete for a radiant heat flooring pour, you will need to make it slightly more sloppy than usual, so it runs into all the possible cracks through which heat might be able to escape. Mix up the concrete mixture as recommended on the packet, and then mix in water and sand until you are satisfied with the consistency of the concrete. If you are concerned about cracking or damage, you can also add reinforcing fiber to the mix, in order to limit this problem. Make sure there are no large lumps, and then proceed to pour the mixture.

Step 3 - Pour the Concrete

When you begin to pour the mixture, it is a good idea to get some hot water and allow it to flow through the radiant heat tubes. As the hot water travels across the under-flooring, pour the concrete slowly and steadily across the floor. The tubes themselves are quite tough, and are usually laid far enough apart that you can fit plywood sheets between the tubing, so if you need to move your concrete across the area, you can spread the weight a little. If you intend to use a concrete pump kit, then you should be prepared to lift the hose, rather than pull it across the tubing, as there may be steel bonds on the hose that can damage or even puncture your new tubes.

Once the concrete has been poured, level it off with the plywood sheets, and leave it to dry before flushing hot water through the tubes for a second time. You can now lay whatever board or carpet you choose.