FLOOR COVERINGS AND UNDERFLOOR HEATING
WATCH OUT
Underfloor heating is now the heating system of choice for most new buildings and certain criteria need to be understood as to the effect of underfloor heating when any covering is placed on a floor with underfloor heating in it.
The operation of any underfloor heating system relies upon the output of the floor to heat the room or property. Any covering over the floor will limit the heat output available. For most applications the normal finished floor temperature will need to be in the range of 23 to 27 degrees C to provide the necessary heating required. If any covering is placed over the heated floor the thermal resistance of the covering will mean that there will be a temperature drop from the underside of the covering to the covering floor surface. This will result in a lower floor surface temperature on the covering and hence a lower output and room temperature.
As
an example -a concrete floor with a design floor temperature of 26°
C.
Installing a floor covering with a resistance of (say) 0.17 onto this
floor will result in a temperature drop through the covering of 6 degrees,
from 26 ° C to 21 ° C.
As this drop in floor temperature would result in a lack of heating,
the temperature of the concrete floor has to be increased by 6 °
C to 32 ° C, which will provide the final finished floor design
temperature on the top of the covering of 26 ° C.
As this illustrates the resistance of the floor covering used is very important, as this will directly affect the floor heating output.
All coverings for use on floors should comply with British Standard 8302 code of practice, which states that the floor surface temperature should be able of operating at 27 ° C.
Warmafloor Underfloor Heating In Timber Flooring at St Mary's Church
Whilst manufacturers of Carpets, Underlays and Timber Flooring have addressed the issues with using underfloor heating and their products, tested the products and can provide technical information, the Contract Flooring Association and The UK Resilient Floorcovering Manufacturers Association, which represent most of the floorcovering industry, have not.
They have adopted a misleading technical guideline that states that their systems are suitable for use with underfloor heating, but only if the 27 ° C temperature referred to in the British Standard is at the glueline position, (i.e. beneath the floor covering) not on top of their floor coverings and that if this temperature is exceeded their warranties will be invalidated.
Clearly,
as illustrated above, keeping to a temperature of 27° C. below most
coverings will result in too low a final floor surface temperature and
the majority of underfloor heating systems will be unable to operate satisfactory
What is actually happening in practice is that these coverings are being
installed over underfloor heating systems, and to enable them to operate
satisfactorily they are being run at much higher temperatures than the
recommended 27° C. This will in all cases invalidate the manufacturers
warrantee and in some cases cause floor failure, the customers picking
up the bill.
To avoid this most unsatisfactory situation the manufacturers need to recognise that underfloor heating has arrived and carry out testing of their products to determine, dependent upon the products thermal resistance and properties, which ones are capable of complying with the British standard of 27 ° C surface temperature and which ones are suitable for use with underfloor heating.
This information is required for all flooring products so that clear product technical guidelines can be issued, mistakes can be avoided, and the end user who pays the bills is properly advised as they are with carpet, underlay and wood flooring manufacturers who have got their act together.
So- until the manufacturers sort themselves out, always obtain confirmation from the selected floor covering manufacturer that their product is suitable for fitting over underfloor heating at the necessary floor temperature.
Warmafloor UK. Concorde House, Concorde Way, Segensworth North,
Fareham, Hampshire, PO15 5RL
TEL : 01489 581787 FAX: 01489 576444