In-screed Cross Section

Wall/Edging Insulation

Fix the edge insulation continuously around all internal walls.

When installed correctly the perimeter edging skirt will be facing out. Tape this onto the floor insulation.

Once the screed has dried and cured, the edging insulation can be trimmed down.

Remember the Following:

The maximum circuit length we recommend is 100m, as to avoid excessive temperature and pressure drops in your underfloor heating system.

If your area requires more than 100m, you can divide the amount in half and fit two circuits of similar length. For example, a room area of 30m² with 200mm pipe centres require 150m of pipe. Fix with 2 circuits of 75m.

Pipe connections must not be made in the area to be screeded. Don’t forget to allow for connection lengths back to the manifold in overall circuit design and length.

Pipe Centres

The pipe should be spaced 100mm away from the wall. Always go with making sure it flows to the coldest part of the room first e.g. under windows, along outside walls etc.

In solid screed floors and areas of average to low heat loss, UFH pipe is generally laid at standard centres of 200mm, unless otherwise specified.

The two most common ways to install the pipe into the floor insulation is either to use pipe clips or using the grip rail system.

Pipe Clips Fixing

To fix the pipe into place, use the pipe clips.
We recommend having two people to fit the pipe, one person to hold the coil and another person to clip the pipe into the insulation.

You need approximately 2 clips per metre of pipe.

Rail System Fixing

With this type of installation lay the rail across the floor to create a matrix for the pipe.

Rails have the self-adhesive backing so you can easily stick them to the insulation. Set them with a maximum of 500mm from two opposite wall edges and a maximum of 1000mm spacing between clip rails. Make sure that the rail is at a 90° angle to the coldest external wall.

Once you are happy with the clip rail layout, fix them permanently to the insulation using additional pipe clips. Also, make sure that the pipe turns are secured with additional pipe clips.

Try to use all the pipework supplied. The pipe is marked every metre so you know when it’s time to go back to the control unit. UFH pipe isn’t normally laid under fixed furniture such as kitchen and utility units.


We recommend 65mm of screed on top of the insulation (Building Regulations requirements).
The screed must be allowed to dry before heating is operated. The general rule is to allow 1 day per 1 mm of screed.

As the system is used for the first time, the mixing valve must be set to the minimum setting to let the moisture in the screed to dry out. The temperature should be increased by 2 degrees every day until the mixing valve is set at 45°C.