7mm cables, also known as in-screed cables, are used to provide underfloor heating in many different circumstances as they are particularly versatile product. The most common use for in-screed cable is in new-build and major renovation work where the cable is laid onto an insulation layer, such as Cellotex Double-R, and a 65mm screed is poured on top. Virtually any floor layer can then be laid on top of the screed and the screed bed itself can run as a heat sink, providing an exceptionally stable floor and room temperature.
An alternative construction involves laying in-screed cables beneath joists beneath floor boards and this method is sometimes used in stately homes and listed buildings as it does not alter the fabric of the building. The cable itself is usually the least expensive option to provide underfloor heating if you are already going to be laying a new screed.
In-screed cables can also be used outside beneath walkways and drives for external frost and snow melting and the same cable can provide heating to prevent icicles or snow build up on roofs.