Below are guidelines on how to design your UFH installation.

Before you commence your installation take time to design your pipe layout to use the maximum

amount of pipe but be careful to make an allowance for the location of the control unit. Set the

pipework in 100mm from all walls/edges.

As the temperature of the UFH system is controlled by the Blending Valve in the Control Unit,

reducing the pipe centres does not increase the room temperature but does reduce the heat up time.

Use the chart below along with the area of your room to determine the optimum pipe spacing. The

spacing is described as c/c; this is the distance between the centreline of the pipes.

Room Size Coil c/c Blending ValveTemperature

25 m2 100 m 300 mm 48

20 m2 100 m 200 mm 45

15 m2 100 m 150 mm 44

If the room is smaller than 15m2 it is still recommended to use as much pipe as possible. But,

normally c/c 150mm is the minimum spacing.

We recommend setting the water temperature at 45°C for screeded floors, which can be increased to

48°C if larger pipe centres are used to achieve a maximum floor temperature of 29°C.

If a timber floor finish or floating floor is proposed set the Blending Valve to achieve a maximum floor

temperature of 27°C to avoid shrinkage of the timber boards.

Note we do not supply the insulation. Any builder’s merchant will have Celotex or Kingspan insulation

in stock. The quote is based on clipping the pipe direct to the insulation board. We do supply pipe

clips. We recommend 65 mm of screed on top of the insulation for concrete floors, for timber

suspended floors see this document.

The screed must be allowed to dry for a minimum of 4 to 6 weeks before the heating is operated. As

the system is used for the first time, the mixing valve must be set to minimum setting to let the

moisture in the screed to dry out. The temperature should be increased by two degrees every day

until the mixing valve is set at 45°C. Floorboards must have moisture content lower than 7 % before

they are installed. We do not recommend floorboards thicker than 25 mm, see website link under

technical for more information about floorboards. Always check with the manufacturers of any floor

finish that it will work with underfloor heating.

For stone and ceramics tiles it is recommended that flexible adhesives and grout are used. Avoid

underlays for carpet with felt and rubber crumb type. With Vinyl check the vinyl floor manufacturer

that it works with underfloor heating. Laminate flooring should have an expansion gap for movement.