Cast into the slab
In-slab electric underfloor heating
Armoured heating cable cast into the concrete slab, under a wide range of floor coverings.
In-slab electric heating
In-slab electric heating puts the cable inside the structural slab, so the concrete itself becomes the heat store. The CT 30 cable emits very low EMF and is easily installed into the slab under a wide range of floor coverings.
The steel armour and the layers of conductor insulation make the cable durable enough to survive a pour and a concrete vibrator, and durable enough that the same cable is used for snow melting.
Like any in-slab system it is slow to react and slow to cool, so it is run on a long charge rather than switched on and off. That is why it is intended for a time-of-use tariff, where the slab is charged on cheaper overnight power and gives the heat back through the day.
Installation
The cable is tied to the reinforcing mesh at the spacing the room needs, then the slab is poured over it. We recommend extruded polystyrene insulation under the slab and around the exposed slab edge to improve warm-up time and reduce running costs.
A floor sensor is run into a conduit so it can be replaced without breaking into concrete. The cable is tested for resistance and insulation before the pour, during it, and again afterwards.
A licensed electrician connects the thermostat on a dedicated circuit with residual current protection. Larger slabs are split into zones so each area can be controlled separately.
Things to consider
- Best suited to new slabs, so it has to be programmed in before the pour
- Rated to 30 watts per metre
- Slow to warm and slow to cool
- XPS insulation under the slab is strongly recommended
- Intended for use on a time-of-use tariff
- Suits most floor coverings, including polished concrete
Installation photos
