Komfort underfloor heating Technical Notes and FAQ

	• Underfloor heating frees valuable wall space and gives greater flexibility to room layouts.
Underfloor heating is increasingly specified and installed in the UK for a large variety of buildings including houses, hospitals, leisure centres, schools and sports centres.
	• Underfloor heating is safer because, unlike radiators, there are no hot surfaces that can present a burns hazard.
	• Underfloor heating is very effective in rooms with high ceilings because its low surface temperature radiates heat upwards slowly to a height of approximately 2 metres

Specialist pipe-work laid in the screed or below the floor in floating or suspended applications, raises the temperature of the floor surface and releases heat into the room. Levels of comfort are greater than other forms of warmth, because 50% of underfloor heating rises vertically as warm, convected air. With typical floor temperatures of 25° to 29°C, the floor is comfortable to walk on even when traditionally cold materials, such as quarry tiles, ceramics or stone flags are used as the floor covering.

Screed Curing
	A curing period of 21 days for cement screeds, or 7 days with anhydrite screeds must be allowed before heat can be applied for pre-conditioning.
	Initially, on the first day, heat should be applied to the floor screed using warm water at 30-35ºC, after which the flow temperature can be raised by 5ºC per day until the required temperature is reached.
	Ambient Temperatures
	The underfloor heating pipework should not be laid with ambient temperatures of below –5ºC. Screeds should not be laid with ambient temperatures of below 5ºC.
Wood Floors
	Before timber flooring is laid on heated screeds, the screed must have been cured and conditioned previously, to a moisture content of approximately 0.5% (carbide method) by heating to the operating condition for 5 days. It is not recommended to lay timber floors which have a moisture content in excess of 8-9% (by volume), as the risk of warping and shrinkage will become unacceptable. The timber manufacturer’s instructions must be observed. The operational surface temperature of wood floors should not exceed 27ºC as this carries a risk of shrinkage. Subsequent cooling may result in swelling, as extra moisture becomes absorbed into the wood from the atmosphere.
Ceramic Tiles on Wooden Floors
	Renovation projects containing ceramic floor tiles on timber subfloors require extra care. All floor board substructures need to be replaced or overlaid with large sheets of plywood to ensure minimum flex movement, and should be secured using adhesive or nails at 150mm spacing. Ceramic tile adhesive must contain a flexible latex admixture to allow micro-movement of tiles during the normal operation of the floor heating system. Failure to carry out these instructions could result in damage to the pipework, screed or floor covering.

	Underfloor System Types
	The Komfort screeded system comprises an edging strip which is laid against all internal perimeter walls, providing edge insulation and an expansion zone for the screed.
	Insulation is then laid onto the concrete slab. To ensure adequate insulating properties, a range of thicknesses is available.
	The underfloor heating pipe is fitted to the manifold by a mechanical connection and is then laid out in the required patterns, as per the Komfort layout drawings supplied. Pipes are held in place with U-clips. Underfloor heating layouts are designed to have no joints in the pipe other than at the manifold, thereby minimizing the risk of leakage.
	Prior to the screed being laid, the underfloor heating pipe-work is pressure-tested, using either water or air, to ensure that any damage resulting in a leak is immediately obvious. Following curing of the screed the heating can be turned on and the flow temperature slowly elevated.
	The standard cement screed requires no special additives and, in most circumstances, should be 75mm thick: lesser thicknesses can be applied when required by using special screeds, such as anhydrite.

Specifically designed for underfloor application, our PERT Midi Composite pipe with oxygen diffusion barrier is very strong and extremely flexible, making it much easier to lay than most other pipes.

DESIGN
Upon an order being placed, and from your detailed architectural specifications, we will produce and supply you with full pipe layout drawings, heat loss calculations, flow rate and pump duties to allow the installation to be carried out professionally.