What is the best floor covering for underfloor heating?
The majority of popular floor coverings are suitable for use with underfloor heating (UFH), with some offering a better heat transfer than others.
The best floor coverings to pair with UFH are hard surfaces such as stone or ceramic tiles. Tiles are the most thermally conductive floor finish, transferring heat from the UFH to the surface of the floor quickly and with little resistance.
Although tile is the best choice, there are still many other options that work well and are regularly laid over an UFH system including carpet, engineered wood, laminate and vinyl.
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Laminates and engineered wood, such as Kahrs flooring, have a good structural stability that allows them to perform well with UFH without the risk of warping. An engineered wood floor can be laid directly over the UFH as a ‘floating floor’ or nailed to battens of joists.
Solid hardwoods and softwoods also transfer heat well but care should be taken when specifying board width and thickness.
UFH can be used with most types of carpet. By choosing an underlay that is not a good thermal insulator, heat will easily pass through this layer into the carpet itself. The overall Tog value of the carpet and underlay combined should not exceed 2.5 and the underlay should not exceed 1 Tog. Felt and polyurethane underlays should be avoided as they affect heat transfer.
Tiles offer a high thermal conductivity and slim profile that makes them particularly popular for using over UFH in kitchens and bathrooms.
Before laying a tile finish over UFH, a de-coupling membrane and quality flexible adhesive should be used. This prevents any concentration cracks from being transmitted through to the floor covering.
Vinyl floor tiles, such as Karndean and Amtico, are available in a range of finishes and are very durable, making them a popular floor covering choice that is also compatible with UFH.
As a sensitive floor covering, a floor temperature sensor should be fitted. This will limit the heat output from the UFH (usually to 27°C) to protect the vinyl or lino from any discolouration. For this reason, vinyl and lino is not recommended for areas with high heat losses such as conservatories.
Due to their tough and durable finish, the use of polished screeds and synthetic resins in domestic properties is becoming more common. As screed, by nature, is very conductive it is well suited for use with UFH and by pairing the two together it also takes away the ‘cold touch’ associated with choosing a hard floor covering.
With the majority of retrofit, floating and first floor underfloor heating systems, you can fit floor coverings immediately or the very next day. This is because there are no wet screeds or compounds that take time to dry.
For screed systems, typically used in new builds, you have to wait until the screed is completely dry before laying any floor coverings. Screed tends to dry at a rate of 1mm per day, meaning a wait of between 40-60 days depending on its thickness.
This varies on the choice of UFH system and floor covering.
For tiles, a decoupling membrane and quality tile adhesive should always be used. For other floor coverings, particularly vinyls and woods, the manufacturer will provide guidance.
It is advisable, where practical, to commission and heat the UFH for up to 72 hours before then leaving it to completely cool as this will remove any residual moisture present in the floor.
For more information on how floor coverings should be laid over UFH, read our selection of data sheets linked above.
If a tile floor finish or vinyl has been laid, it is best to wait between 24-48 hours before turning the UFH on to allow any adhesives to dry.
If you’d like to discuss the best flooring for underfloor heating, one of our experts will be happy to help on 01404 540650.