How much expansion gap for laminate flooring? 8 to 12 mm, and where it goes
Updated 12 August 2026
Laminate flooring needs an 8 to 12 mm (about 5/16 to 1/2 in) expansion gap at every wall and every fixed object, because laminate and LVT expand and contract with humidity, and a floor with nowhere to go buckles upward. The gap is a manufacturer requirement (and warranty condition), it is invisible once the skirting or trim covers it, and forgetting it around one pipe or doorway can lift a whole room. Long rooms need one thing more: an expansion joint partway across the run, covered below.
If you want the answer for your own room without reading further, the expansion gap calculator takes your room size and material and returns the gap, your laying area and the expansion joint verdict.
The numbers
| Situation | Gap |
|---|---|
| Standard room, every wall | 8 to 12 mm (10 mm typical) |
| Rooms over about 8 m in either direction | 12 mm, and check for a mid-floor break requirement |
| Around pipes | pipe diameter + 20 mm hole |
| At door frames / architraves | same gap, or undercut the frame and slide the board beneath |
| At fixed objects (island, hearth, columns) | same gap as walls, all the way round |
| At thresholds between rooms | gap under the threshold profile |
The floor moves as a single raft, which is why the gap must go around everything, not just the walls you can see. A kitchen island bolted through the boards, or one tight pipe hole, pins the raft at that point; the floor then expands against the pin and lifts into peaks around it, or shrinks away from it and drags gaps open at the joints.
Where people actually miss the gap
- Radiator pipes. The hole gets drilled snug because a big hole "looks wrong". Drill pipe plus 20 mm (about 3/4 in); a two-part pipe rosette hides it completely.
- Door frames. Cutting boards tight to the architrave. Undercut the frame with a handsaw laid flat on an offcut, slide the board under, keep the gap behind. Details in flooring around doorways and pipes.
- The last row. The row is ripped to width, and it's tempting to fill the space fully. The rip width must include the gap: measure to the wall, subtract the gap, then cut. See planning the first and last row.
- Heavy furniture across a doorway line. A wardrobe in one room, a sofa in the next, both pinning the same raft, works like two walls with no gap. Large connected areas often need a break at the doorway (a threshold profile) precisely for this.
When does laminate need an expansion joint?
A perimeter gap handles normal rooms. Once a floor runs past roughly 8 m (about 26 ft) in either direction (some ranges say 10 m, some 6 m for wide open plans), the raft is moving too much for the edges alone, and the manufacturer's sheet will require an expansion joint: a deliberate break in the floor, covered with a threshold or expansion profile.
| Run length | What you need |
|---|---|
| Up to about 8 m | Perimeter gap only |
| Over about 8 m in either direction | Expansion joint partway along the run |
| Between rooms through a doorway | Joint under the door line in most ranges |
| Open plan L-shapes | Joint where the legs meet, or at the natural pinch point |
The doorway is the natural place to put the joint, because the profile sits under the door and reads as a threshold rather than a break. Whether you can run one floor continuously between rooms without a joint depends on the combined run staying inside the maximum, and on both rooms getting their own perimeter gaps regardless.
What if the expansion gap is too big?
An oversized gap never damages the floor; the risk is cosmetic. Skirting covers 12 to 15 mm (about 1/2 to 5/8 in) comfortably, scotia a little less, so a gap wider than the cover strip shows as a shadow line at the wall. The fixes, in order of effort: fit a deeper scotia, pack the skirting out a few millimetres, or recut the edge row. Never fill the gap with caulk or offcuts to close it up, because that pins the raft exactly where it needs to move.
Planning gaps, not just leaving them
The gap changes your measurements, not just your fitting:
- The laying area is the room minus the gap on every side. On a 4 m (about 13 ft) wide room, 10 mm (about 3/8 in) per side removes 20 mm, occasionally exactly the difference between a comfortable last row and a sliver.
- Every obstacle's cut-out grows by the gap all round.
- Spacer blocks set the gap during laying; the skirting or scotia covers it after. If the existing skirting stays, the cover strip's width limits your maximum gap, so check before committing to 12 mm.
When the designer lays out a room it works from the laying area, with walls and obstacles already inset by the gap, so the pack count and the last-row width come out right. Measuring for it is covered in how to measure a room for flooring.
LVT, engineered and the exceptions
- Click LVT floats like laminate: same rules, sometimes smaller gaps (check the sheet, since rigid-core boards move less).
- Glue-down LVT is bonded, not floating: perimeter gaps shrink to a few millimetres or none, per the adhesive spec.
- Engineered wood floated: same as laminate. Glued or nailed: follow the system's own rules.
When in doubt, the manufacturer's installation sheet wins, because it is the document the warranty refers to.
Frequently asked questions
- How big should the expansion gap be for laminate?
- 8 to 12 mm (about 5/16 to 1/2 in) at every wall and fixed object, with 10 mm (about 3/8 in) the common recommendation. Larger rooms need the larger figure; check your manufacturer's sheet, as it is a warranty condition.
- Do I need an expansion gap around pipes and door frames?
- Yes, everywhere the floor meets something fixed: walls, pipes, columns, kitchen islands, hearths and thresholds. Radiator pipes get a hole 20 mm larger than the pipe, covered with a pipe rosette.
- What happens if you don't leave an expansion gap?
- The floor expands against the wall, has nowhere to go, and buckles upward, usually at the middle of the room, usually in the first humid season. Repair means taking up boards back to the wall and recutting.
- When does laminate need an expansion joint, not just a gap?
- On runs longer than about 8 m (about 26 ft) in either direction, and usually at doorways between rooms. The joint is a small break in the floor covered by a threshold profile, and most manufacturers make it a warranty condition on long runs.
- What if my expansion gap is too big?
- Nothing fails, but the skirting or scotia may no longer cover it. Standard skirting hides 12 to 15 mm comfortably. If the gap is wider at one point, pack the skirting out, fit a deeper scotia, or recut the edge row rather than filling the gap.
- Does LVT need an expansion gap?
- Click LVT floats like laminate and needs the same treatment, though rigid-core boards move less and some sheets allow smaller gaps. Glue-down LVT is bonded, so its perimeter gaps shrink to a few millimetres or none. The installation sheet wins.