Specifinder  

Suitability of different floor finishes with underfloor heating

The guide below will help you make the right decision in choosing the best flooring for your space.

The sheer comfort of underfloor heating systems both electric and water-powered, means many are looking at it as an alternative to radiator systems. For some it’s also about the interior design advantages of being able to remove radiators from walls. And though the Energy Saving Trust has estimated that in new, well-insulated homes there is little savings over using radiator systems, others have suggested the energy saving can be up to two-thirds that of conventional heating systems. But when choosing an underfloor heating system it is also essential to consider the floor finish that is going to make your heating system as effective possible.

Minitec by Uponor

The choice of floor finishes for underfloor heating is as varied as for conventional floors – though unfortunately that lovely rug you may have spotted to put in your living room will have to be shelved as rugs aren’t recommended for obvious reasons.

The key feature is to look for flooring with good thermal conductivity as it will heat the room up more quickly and more efficiently. In general, you will need to check with the maker of your underfloor heating system as to the suitability of your choice. Likewise check with the supplier of your flooring as to the need for underlay or not as this will also impact on the overall effectiveness of the system.

Read on for detailed information on underfloor heating across the range of flooring.

Stone

Though stone and tile floors look elegant they can sometimes feel a little chilly, but when it comes to underfloor heating floor finishes they are the perfect heat conductor. Tile, stone, ceramics, slate all heat up quickly and retain heat. How quickly these materials heat up will of course depend on the thickness of the tiles but when they heat up, both thick and thin tiles are equally effective in conducting heat well. Good insulation will make a difference both to the responsiveness of heat coming through and prevent heat loss.

Carpet

Array & Broadrib by Heckmondwike

Though carpet is a good insulator, which may lead you to think it’s not the material to use with underfloor heating, The Carpet Foundation carried out research with the Underfloor Heating Manufacturers Association (UHMA) showing that as long as you have the correct tog value of carpet it is perfectly suitable. Tog value measures the thermal insulation and as long as the underlay and carpet combined doesn’t exceed 2.5 tog the system should work well. With carpet (as with wood, laminate and vinyl) there is generally a temperature restriction of 27 degrees.  The Carpet Foundation recommend consulting the heating manufacturer to check that the choice of carpet/underlay combination will work with your system.

Wood

Lightly fumed & smoked micro-bevelled oak parquet by The Solid Wood Flooring Company

Wood flooring is a popular choice but you need to be aware of the different thermal properties of the woods and the degree of moisture content. Hardwood should have no more than 8% moisture content. As the wood is heated and cools down it changes, so the most suitable wood will adapt to changes in temperature without warping or shrinking. Which is why some recommend leaving the system on at a low temperature. There will need to be an expansion gap around the edges of the flooring which can be concealed by skirting board. Thicker and less dense wood will function as an insulator, so a wood that is dense and thin conducts heat better. Many experts suggest that the thickness of the wood should be no more than 22mm. Underlay is only necessary for floating wood floors. Like carpet the floor surface temperature shouldn’t be more than 27°C.

Engineered and Bamboo

testEngineered natural strand woven Unicli by The Bamboo Flooring Company

Made from natural materials, engineered wood is generally recommended because its stability means it deals better with changes in temperature. The top layer will be a hardwood and the bottom layers will often be soft woods. Bamboo is also an effective conductor of heat so is also a good choice. Surface temperature shouldn’t be more than 27°C.

Laminate

The laminate is designed to look like real wood and modern laminates are highly effective in delivering a natural look. They are hard-wearing floors made to resist scratches and stains and offer good value. Surface temperature shouldn’t be more than 27°C.

Vinyl

Designatex PUR by Polyflor

Luxury vinyl tiles have become increasingly popular and vinyl is very suitable for underfloor heating systems. The thinness of the vinyl surfaces means it is very responsive, warming up and cooling down quickly. You will need to check with the maker of your system as to the recommended subfloor. Surface temperature shouldn’t be more than 27°C. 

Screed

With an underfloor heating system a leveling screed requires a flooring surface, however a wearing screed can be used on its own. The advantage of a concrete floor for an UFH is that it retains heat well, staying warm long after the system has been turned off. The water temperature of the system can be lower than in wood suspended floor. Equally because it takes longer to heat up, it may be advisable to keep the system on at a steady heat throughout the winter months. The UFH system will monitor the temperature and use energy efficiently. Like other surfaces insulation below the system is necessary to make sure the heat flows upwards.  

There are a variety of screeds available, the traditional sand and cement, fast drying and anhydrite. While an anhydrite screed is particularly suitable for being poured over large spaces (office buildings), they also have longer drying times.  The ideal thickness of a traditional sand and cement screed is between 65mm-75mm in order to give the screed strength and prevent it from cracking, of liquid screed it is slightly less, around 50 mm.  Fast-drying screeds are helpful when using other floor finishes, the system can be used earlier and the flooring van be laid sooner.