Main menu: (access keys 1 to 8)

1. 
2. Company
3. Systems
4. Products
5. News and Events
6. Knowledge Centre
7. Contact

1. Screed & concrete floors
2. Structural concrete
3. Timber susp. & batten
4. Timber floating floors
5. Raised access floors
6. Sports floors
7. Electric Underfloor

Sports halls, Assembly halls and dance studios etc.

Underfloor Heating can be installed in most types of wooden floors quite effectively. Care must be taken in the design of the system and the flooring materials used to ensure a trouble free system.

Floor types

There are a wide variety of timber floors available for varying purposes from sports, to dance; also they have a wide range of different floor finishes. They either fit directly onto the floor screed or will be mounted on floor battens of various types. In our opinion wooden floors are best if fitted over a heated screed as the screed acts as an energy store during off periods retaining some heat, whereas a completely wooden system looses all its heat as the system is lightweight and needs more time to heat up when cold.

Heat Output

The Heat Output from a wooden floor system is limited by the timber floor itself. As timber is an insulant, it restricts the available heat that can penetrate through it. The maximum output through the floor is:

Between 70 and 75 watts per square meter of floor, whereas a concrete/screeded floor can provide 100 watts per square meter.

This however is not a problem in a modern building where heat output required is generally in the range of 30 to 65 watts per square meter.

The most suitable timber floors are those with the lowest resistance to heat transfer, so floors which rely on a thick foam underlay below the floor to provide sufficient spring are normally unsuitable.

*To illustrate this is an example

If the underfloor system is in a building with various floor finishes, i.e. some screeded floor with lino, some with thin carpet and some with timber and the underfloor heating running at the same mean temperature for all floor types, clearly the output from the timber floor will be less at the same mean temperature and pipe spacing which may be insufficient to heat that room So the underfloor heating mean flow temperature will have to be increased locally in the wood floor area to take into account of this reduction. This will mean that a separate circuit, at a different mean temperature may have to be used.

Air gaps between heated screed and timber floors

It is often stated that in battened floors with an air gap between a heated screed and a timber floor will reduce output.

However this is not the case. We have installed systems in this method for a number of years. Having a complete heated screeded floor below the timber floor results in a much larger heated floor surface area being available. This radiates to the underside of the timber floor providing a uniform heat over the surface area instead of more localized heat that occurs with diffusion plates, so the output is the same if not greater and the floor surface temperature variations are much less which is better for the timber floor itself.

An additional benefit is that the timber floor installation is much faster and there is no interface between the underfloor system and the floor above.

Chipboard and Plywood Floors

Using underfloor heating with chipboard or plywood floors generally presents no problems, providing the thickness of the flooring is kept to reasonable limits.

Hardwood Floors

Careful specification is required in each instance to ensure lifelong structural stability and performance of Hardwood floors. Wood, being a hygroscopic material, is very susceptible to movement when exposed to different humidity levels. Timber absorbs moisture from the atmosphere when humidity is high (normally during the summer months), causing expansion; whilst in the winter months when the heating system is in operation and humidity is low, the timber will shrink. This expansion and contraction is most noticeable across the width of a piece of wood and in some cases, particularly with Boarded floors, the compound effect may add up to several inches of movement across a room width. Therefore, if traditionally machined tongued and grooved boards are installed in such an environment, be prepared to accept large amounts of movement in the floor.

Laminate Harwood Floors

To overcome the problems associated with Hardwood plank floors, a number of flooring companies now produce Laminate Hardwood Floors. These consist of layer(s) of plywood with Hardwood Veneers or plastic finishes bonded to the surface. This construction method offers a sound and stable solution which avoid most shrinkage and gaping problems associated with timber.

Suitability

To determine the suitability of any flooring for use over underfloor heating the following information from the client/architect is required.

• Flooring manufacturer.
• Manufacturers floor type.
• Floor section with dimensions.
• Floor resistance
• Manufacturers installation data sheet with particular reference to fitting over underfloor heating

Warmafloor has fitted underfloor heating in conjunction with numerous types of timber floors including the following manufacturers:- Junkers, Boen sports floors, Gransprung, Harlequin, Forerunner and Pulastic

Some of the common floor types in more general use a detailed below.

• Boen Boflex
• Junkers Blubat
• Gransprung