In Screed

Floor Style – In Screed Hydronic Heating

There are two advantages of this system over in slab. The first is that it eliminates possible delays with the concrete pour of slabs, which can often be on the critical path for a building’s construction program. The second is that in screed systems can be more responsive with the use of under screed insulation, as this reduces the thermal mass of the system. That means a shorter warm up and cool down period.

After the construction slab is poured we install the Hydronic heating pipes onto special foam insulation board that sit on top of the construction slab. A screed is then poured over the pipe for tiles or finished floor covering. This method requires careful planning as the additional height for the insulation board, piping and screed adds approximately 50mm to 100mm of height above the construction slab – (this may have serious flow on effects on the windows, doors, stairs and ceiling heights so careful planning must be made at the design phase of the build to cater for the required materials and increased floor height).

Typical In Screed Construction

This is a much more agile form of heating from the floor – it is possible to have different zones through the different floor coils and is much more responsive in the time it takes to reach temperature because it only has to heat a thinner screed of concrete. The heat that travels downwards is reflected back up from the insulation board back into the room above. Each zone is controlled by a room thermostat allowing different temperatures in different rooms.

The downside to this form of underfloor heating is the cost. On average it costs about 50% more than an in-slab system. On top of that you need to allow for two concrete pours which is quite expensive.




  • Residential, commercial or industrial
  • Over any suitable floor structure

  • Pipe laid over insulation or tied to light steel mesh
  • Additional reinforcement may be required
  • Minimum 45mm cover on top of pipes
  • Pipe external diameter of 16mm typically used for residential applications