What is an expansion gap?
An expansion gap (in Dutch zwelnaad or zwelruimte) is the free space you leave between a floating floor, such as laminate or parquet, and the wall. Wood and wood-based materials expand when humidity rises and shrink again when it gets drier. Without an expansion gap the floor pushes against the wall and can buckle, cup or break its joints.
It is usually a gap of about 8 to 10 millimetres all round. The exact size is set by the floor manufacturer; large floor areas may need more, or an additional expansion joint within the floor itself.
Where do you need an expansion gap?
- Along all walls, including behind radiators and fitted cupboards.
- Around pipes, such as heating pipes coming up through the floor.
- At door frames, thresholds and stairs: the floor must not be trapped anywhere.
- At transitions to another room or floor type, usually finished with a threshold profile.
How it is made
The gap is created with spacers (spacer wedges) placed between floor and wall during installation. Afterwards they are removed and the gap is covered with a skirting board. The skirting is fixed to the wall, not to the floor, so the floor can move freely underneath.
Handy: thin cables can be hidden in the expansion gap behind a stick-on skirting. The downside is that you have to remove the skirting if you want to add a cable later.
Common mistakes
- Sealing the gap: a floor stuck to the wall with sealant can no longer move.
- Screwing the skirting to the floor or pressing it down too hard.
- Forgetting spacers on the last row or at door frames, where fitting is hardest.
- Not acclimatising the floor: leave the packs in the room beforehand as the manufacturer advises.
Related terms
- Expansion joint
- Parquet floor
- Skirting board
- Expanding grout
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