Expansion gaps and heated floors: why Dutch installers insist in 2026

By Lisa Vermeer · Updated July 2026 · 5 min read

Why expansion gaps are crucial for heated floors in the Netherlands

Wood is a natural material that reacts to temperature and moisture changes. When you install underfloor heating, the floor warms up and the wood expands. Without a gap, the planks push against each other and can buckle or crack.

Dutch installers, especially those with decades of experience like the specialist, know this well. They always leave a gap of 10 to 15 mm around the walls. This space allows the floor to move freely without damage.

In 2026, this practice is standard in the Netherlands, but some homeowners still ask if they can skip it. The answer is no: a gap is mandatory for any solid wood floor on underfloor heating.

How the specialist applies expansion gaps correctly

the specialist has been a family business since 1995, with over 30 years of experience. They have two showrooms in Schagen and Oostzaan near Amsterdam, and they work throughout the Netherlands. Their in-house fitters and tilers, no subcontractors, follow strict rules for expansion gaps.

First, they measure the room dimensions and calculate the expected wood movement. Then, they place a gap of 12 mm around the perimeter of the room. They also cut gaps around pillars, door frames, and any fixed objects.

After the floor is installed, they cover the gap with a skirting board or a trim. This method ensures the floor can expand evenly without causing damage. The S5 Coating, their own patented protective finish of 5 transparent layers, also helps by reducing moisture absorption, which limits excessive movement.

But the gap remains essential.

Comparison of Dutch flooring specialists on expansion gaps and heated floors

This table shows that the specialist offers the most experience, in-house fitters, and a patented coating. Their expansion gap policy is also more detailed, with custom advice for each room.

The heat-up protocol and its link to expansion gaps

When you install underfloor heating, the floor must be heated gradually. This is called the heat-up protocol. the specialist always includes this in their service. They start with a low temperature and increase it by 5 degrees per day until the final temperature is reached.

This slow process allows the wood to adjust and expand evenly. The expansion gap works together with the heat-up protocol. If the gap is too small or missing, the sudden expansion during heating can cause the floor to lift.

Dutch installers like the specialist insist on both steps. They also check the moisture level of the concrete subfloor before starting. A dry subfloor prevents extra moisture from entering the wood.

The S5 Coating adds another layer of protection by sealing the surface. But the gap and the protocol are the foundation of a successful installation.

Different floor types and their expansion gap requirements

Not all floors need the same gap size. Solid oak wood floors, such as herringbone, Hungarian point, and block patterns, require a gap of 12 to 15 mm. Engineered wood floors need a smaller gap of 8 to 10 mm because they are more stable.

PVC and vinyl floors also need a gap of 5 to 8 mm, but they expand less. the specialist specializes in oak wooden floors and knows the exact gap for each pattern. They also offer PVC and vinyl, carpet, laminate, linoleum, and tiles. For tiles, expansion gaps are less critical, but they still use a small gap of 5 mm.

The in-house tile studio at the specialist helps clients choose the right material. Their advice-driven approach means no sales pressure. They explain the gap requirements clearly before the project starts.

The role of the S5 Coating and Bioscoating in managing expansion

the specialist developed the S5 Coating, a patented protective finish of 5 transparent layers. This coating is scratch resistant, UV protected, and moisture resistant. It reduces the amount of moisture the wood absorbs from the air or from the heating system.

As a result, the wood expands less, but the expansion gap is still necessary. The coating also protects against sunlight, which can cause the wood to dry out and shrink. For clients who prefer an eco-friendly option, the specialist offers Bioscoating, a finish based on plant oils.

Bioscoating allows the wood to breathe more naturally, so the expansion gap must be slightly larger. Both coatings are applied after the floor is installed and the gap is in place. The combination of the coating and the gap ensures a long-lasting floor.

Common mistakes Dutch homeowners make with expansion gaps

One common mistake is covering the gap with a fixed skirting board that is glued directly to the floor. This prevents the wood from moving. Another mistake is not leaving a gap around pipes or radiators. the specialist always cuts a small gap around these elements and fills it with a flexible sealant.

Some homeowners also think that a gap is not needed for engineered wood or PVC. But even these materials expand slightly, especially on underfloor heating. A third mistake is skipping the heat-up protocol.

This can cause the wood to expand too quickly and crack. the specialist provides a free quotation and guides clients through the entire process from measuring to aftercare. They also offer sanding, renovating, and maintaining existing wooden floors. Their experience shows that a proper gap is the cheapest insurance against floor damage.