Installing underfloor heating systems demands a technical approach and key modifications to construct the floor. You have to be very careful about choosing the right type of material and insulations. All components, like screed, insulating panels, wood, skirting boards, etc., are adjusted step-wise so that the heating system delivers its best with the desired floor design.

Whether you need a concrete or timber floor, following an accurate criterion can deliver the expected results. Let’s go through the essential details of floor construction professionally so that nothing important gets ignored.

Laying Underfloor Heating Pipes in Concrete Floor

Prepare the Base: Lay a damp-proof membrane over the subfloor to prevent moisture from rising. If using a suspended beam and block construction, ensure the base is properly prepared.

Install Edging Insulation: Fix a 20mm thick piece of insulation along the perimeter (external) walls, making sure it extends to the depth of the floor insulation and screed. The edging insulation can consist of plaster, skirting board, or any other suitable material.

Lay Floor Insulation: Cover the entire floor area with floor insulation, and tape the joints to prevent screed from seeping between the insulation boards. The recommended minimum layer of Polyurethane insulation is 50mm, but if space is limited, 30mm can be used.

Managing Underfloor Heating in Concrete and Timber Floors

Polyurethane is preferred over Polystyrene due to its superior performance and greater density, which allows for the use of clip fittings. Ensure all insulation meets current building regulations.

Install Underfloor Heating Pipework: Lay the underfloor heating pipes on top of the floor insulation in the desired configuration. The type of pipe and its layout will vary as per the specific requirements of the building and the heating system.

Add Screed Layer: Finally, lay a 65 – 75mm thick screed on top of the insulation and piping that ensure that the heat diffuses evenly across the whole surface, keeping a constant floor temperature.

Additional Notes

Polystyrene Insulation (50mm): If you are using polystyrene insulation, it is better to use wire mesh on top of the insulation. Moreover, tie the mesh and underfloor heating pipes for better support.

Liquid Screed or Fibre Screed: If you are planning for screeded floors with 50mm fibre or liquid screed, make sure to cover the top of the insulation using a plastic membrane. Additionally, use an edging strip around the walls to contain the screed.

Installing Underfloor Heating in Timber Suspended Floors

Prepare the Insulation: Cut 50mm polyurethane insulation boards to fit tightly between the joists. Utilise scrap battens from the building site to support the insulation from below.

Fix Underfloor Heating Pipes: Use special pipe clips to secure the underfloor heating pipes onto the insulation between the joists. Ensure proper spacing and layout of the pipes according to the heating system design.

Lay Floor Boards: Lay the floorboards on top of the joists, and ensure that the air space between the insulation boards and floorboards is minimum. A gap of 25mm is recommended. Notch the joists where necessary to accommodate the pipe runs.

Fill Air Gap with Lightweight Screed: For better functioning of timber suspended floor and to enable it to work like a screeded floor, it is recommended to fill the air gap between the insulation and the floorboards using a lightweight screed mix. The recommended mix is 10 parts sand to 1-part cement at a height of 25mm.

Managing Underfloor Heating in Concrete and Timber Floors

By filling the air gap with the lightweight screed mix, the timber-suspended floor will distribute heat more efficiently, leading to increased heat output. This method provides a cost-effective and practical solution for installing underfloor heating in timber-suspended floors compared to using expensive heat emission plates.


If you intend to install underfloor heating systems on your house floor, whether it’s of concrete, timber, tile, or any other material, you need to have professional services that would not only give you a quality and well-managed underfloor heating system but also they will make key modifications in your floor so that the system and the floor serve their due purpose.

This is why K M Flow Screed is the best solution to fulfil your expectations of efficient floor construction that genuinely fits your heating system and delivers its best. Hire us for all kinds of floor constructions for underfloor heating systems, and let us provide you with the best services that produce the right value for your invested money.