Installing a Hydronic Radiant Heating System

Types of construction

Hydronic radiant floor systems can be designed and installed for both new homes and existing ones being refurbished. However there are some important issues that home owners should address when installing a hydronic system in an existing house.

It’s of primary importance that the involved parties establish that their building can support the additional weight of the tubing, concrete and cement. Next, installers should ensure that the underside of the sub floor is accessible to allow for installation or maintenance at a later date.


Generally speaking the most popular rooms for radiant floor heating are those that are lived in the most; bathrooms, kitchen and living rooms.

Before the installation begins it’s strongly suggested that a qualified floor specialist make a room by room estimate on the heating load needed for the house. From this estimate designers will be able to figure out the most efficient and effective way of laying the tubing. It’s also beneficial for the homeowner to get a copy of the finished design in case they need to locate the tubing at a later date.

There are three main installation options;

1) Slab-on-grade: A typical way of installing involves compressing the ground that is to be heated and laying a polyethylene vapor barrier on top. Add to this some form of Insulation and place wire mesh or a metal lath on top as it’s easier to attach the tubing than to other materials. It’s worth noting that some installers may also use sand to dry the ground and later on the insulation to hold it in place. This also prevents bubbles from rising up through the poured concrete and spoiling the finish.

Bob Vila Floor Warming Installation

Now that the ground work is complete, the installation of the tubing can begin. The tubing is laid down in the desired formation and tied to the mesh. Run the tubing from each zone up into the connectors and valves and finish the installation by pouring the concrete on top, which should be between 4 and 6 inches in depth.

2) Thin Slab: There are two methods for this installation option, the first involves attaching the tubing to the subfloor and covering it with light concrete (or self leveler). This should give the floor a thickness of around 1.5 inches.

The second method allows for the floor thickness to be only about ½ inch. This is achieved by sandwiching the tubing between the subfloor and the floor covering. Currently there are many different types of underlayment panels that can be used to hold the tubing in place.

3) Dry or ‘Plate’ system: This method involves attaching the tubing to the underside of the subfloor. Should the installation take place in a particularly cold area it is strongly advised that the tubing be attached to well insulated aluminum plates.

Who Can Install a Radiant Heating System

There shouldn’t be a problem finding an installer for radiant heating systems as there are professional installers in most areas of the United States and Canada that specialize in these systems. Any building or plumbing professional can install it.

Whether or not the homeowner can perform the installation on his/her own is entirely up to the local code to dictate, as a license may be required. In some areas the general contractor will allow homeowners to install the tubing while they supervise the work. In most areas, however, a licensed installer is required to install the heat source, especially if a boiler is involved.