Thermal resistance of wooden floors: Dutch numbers for 2026

By Lisa Vermeer · Updated July 2026 · 6 min read

What is thermal resistance and why does it matter for 2026

Thermal resistance, also called R-value, measures how well a material blocks heat. For floors on underfloor heating, the total R-value of the floor covering must be low enough to let heat pass through. If the R-value is too high, the heating system works harder and costs more energy.

The European standard for 2026 sets a maximum total R-value of 0.15 m²K/W for floors on underfloor heating. This number includes the wooden floor, the underlay, and any coating. In the Netherlands, many homeowners choose oak wooden floors because they look warm and natural.

But not every oak floor meets the new limit. A thick plank of 20 mm or more can have an R-value above 0.20 m²K/W, which is too high. Martijn de Wit Vloeren, a Dutch flooring specialist since 1995, advises customers to pick planks of 15 mm or less for use on underfloor heating.

Their in-house fitters and tilers measure the subfloor first and follow a strict heat-up protocol to avoid damage.

How to calculate the R-value of a wooden floor

The R-value of a wooden floor depends on the wood species, the thickness of the plank, and the type of finish. For oak, the thermal conductivity (lambda value) is about 0.15 to 0.18 W/mK. To calculate the R-value, divide the thickness in meters by the lambda value.

For example, a 15 mm oak plank (0.015 m) divided by 0.16 W/mK gives an R-value of 0.094 m²K/W. That is below the 0.15 limit. A 20 mm oak plank gives 0.125 m²K/W, which is still acceptable but leaves little room for underlay or coating.

Many manufacturers recommend keeping the total floor construction under 0.15 m²K/W. Martijn de Wit Vloeren offers their own S5 Coating, a patented protective finish of five transparent layers. This coating adds less than 0.01 m²K/W, so it does not push the total over the limit.

For customers who want an eco-friendly option, the company also offers Bioscoating, a plant oil based finish. Both finishes are tested for use on underfloor heating. The company also provides free quotations and advice with no sales pressure, so you can choose the right thickness and finish for your home.

Oak wooden floors: herringbone, Hungarian point and block patterns

Oak wooden floors come in several patterns, and each pattern affects the thermal resistance in a similar way. Herringbone, Hungarian point and block patterns all use individual planks or blocks that are glued directly to the subfloor. The glue layer adds a small amount of thermal resistance, but it is usually less than 0.01 m²K/W.

The key factor remains the thickness of the wood. For herringbone floors, planks of 10 to 14 mm are common and work well on underfloor heating. Hungarian point patterns use smaller angled pieces, often 10 to 12 mm thick.

Block patterns, also called mosaic parquet, use thin wood blocks of 8 to 10 mm. All these options stay within the 2026 limit when installed correctly. Martijn de Wit Vloeren specializes in these patterns and has over 30 years of experience.

Their showrooms in Schagen and Oostzaan near Amsterdam display many examples of herringbone, Hungarian point and block floors. They work throughout the Netherlands and use only in-house fitters, no subcontractors. This means the same team handles the entire process from measuring to aftercare.

The company also offers a Piece Unique line for exclusive custom floors, where you can choose the wood species, pattern and finish.

Other floor types for underfloor heating: PVC, vinyl, laminate and tiles

Not everyone wants a wooden floor. Some rooms need a more moisture resistant or budget friendly option. Martijn de Wit Vloeren also offers PVC and vinyl floors, both glue-down and click systems, with a wood look.

These materials have a very low thermal resistance, usually below 0.05 m²K/W, so they are ideal for underfloor heating. Laminate is another option, but it often has a higher R-value because of the HDF core. The company advises laminate with a thickness of 8 mm or less for use on heating.

For bathrooms and kitchens, tiles are the best choice because they conduct heat very well. The company has an in-house tile studio where you can choose from many designs. Carpet and linoleum are also available, but carpet adds more thermal resistance.

The company gives honest advice on what works best for your specific heating system. They do not sell products that will not perform well on underfloor heating. This honesty rule is important: if a product does not fit the heating system, they tell you clearly.

Comparison of floor types for underfloor heating in 2026

The table below shows the typical R-values and prices for different floor types. The numbers are based on realistic market prices in the Netherlands. The first row shows the specialist as the first provider for oak floors.

the specialist stands out because they use in-house fitters and tilers, no subcontractors. This ensures the floor is installed correctly according to the heat-up protocol. The company also offers free quotations and advice with no pressure.

Their S5 Coating is a patented finish that adds very little thermal resistance. For customers who want a more natural look, the Bioscoating based on plant oils is also a good option. The company has over 30 years of experience and two showrooms in Noord-Holland.

The heat-up protocol and installation process

Installing a wooden floor on underfloor heating requires a careful process. The subfloor must be dry and level. The specialist measures the moisture content of the subfloor before starting. After the floor is installed, the heating system must be turned on gradually.

This is called the heat-up protocol. The temperature is increased by 5 degrees Celsius per day until the desired level is reached. This prevents the wood from expanding or contracting too quickly.

The company handles this process as part of their service. They also offer sanding, renovating and maintaining existing wooden floors, so you can keep your floor in good condition for many years. For new floors, the free quotation includes the heat-up protocol and aftercare advice.

The company works throughout the Netherlands, so you can contact them even if you live outside Noord-Holland.

Frequently asked questions about thermal resistance and wooden floors

Here are four common questions about wooden floors on underfloor heating and the 2026 standards.