Laminate flooring gaps opening up? Why boards separate and how to close them
23 July 2026
Gaps opening up in laminate come from one of two things: the boards have shrunk, because the room's air is drier than when they went down, or the boards have moved, because the floating floor is pinned somewhere and drags itself apart at the weakest joint. Shrinkage gaps arrive with the heating season, spread across the whole floor as hairlines, and usually close again in spring. Movement gaps sit in one place, keep growing, and need a mechanical fix. Working out which kind you have takes a minute, and it tells you whether to wait for spring or reach for the toolbox.
Why are gaps opening up in my laminate floor?
Match the pattern of your gaps to the cause before touching anything:
| What you see | Likely cause |
|---|---|
| Hairline gaps at many end joints, appeared when the heating came on | Seasonal shrinkage in dry winter air |
| Gaps that appeared a few weeks after fitting | Boards laid without acclimatising, now shrinking to the room |
| One growing gap, with the rest of the floor tight | The floor is pinned nearby and pulls apart at that joint |
| A gap next to a doorway, threshold or heavy furniture | Screwed threshold bar, nailed skirting or pinned units holding one side of the raft |
| Gaps along one wall, with the whole floor drifted | The raft has migrated; often a missing or uneven expansion gap let it wander |
| Gaps plus movement or creaking underfoot | Subfloor dips working the click joints loose |
The first two are the room's climate acting on the boards. The rest are the same underlying fault: a floating floor is one connected raft, and anything that stops part of it moving makes another part take up the slack.
Are gaps in laminate normal in winter?
Small ones, yes. Laminate's core is high-density fibreboard, which is mostly wood, and wood gives off moisture when central heating dries the room out. Indoor humidity in a heated home can drop below 30% in winter from a summer figure of 60% or more, and across that swing each board shrinks slightly. A few hairline end gaps in the coldest months are the floor breathing, not the floor failing.
The test is patience: note the gaps, wait for the heating to go off, and check again in late spring. Seasonal gaps close on their own. If you want fewer of them next winter, steady the room rather than the floor, since keeping humidity roughly between 40 and 60% (a humidifier in winter does it) removes most of the swing. A floor that gapped badly in its very first winter most likely went down without its 48 hours of acclimatisation, locking in a summer size; the acclimatisation guide explains why that first-year settling happens.
How do you fix gaps in laminate flooring?
Never with filler. Hard filler, caulk or glue in the joint pins the raft at that point, and a pinned raft is what causes movement gaps in the first place. Close the gap physically and remove the cause:
- Find and free the pin. Check the area around the gap for skirting or beading nailed through the boards, threshold bars screwed through the floor, tight pipe holes and heavy fitted furniture. Everything fixes to the wall, nothing through the floor.
- Tap end gaps closed from the open side. Near a wall, lift the skirting or trim, use a pull bar on the board end, and tap the run back together. The expansion gap gives you the working room.
- Close mid-floor gaps with a gap fixer. A suction or adhesive block sticks to the drifted board face so you can knock it back with a mallet, with no need to unclick from the wall inwards. A few pounds from any flooring supplier.
- Relock joints that were never fully home. A joint that was not clicked fully closed at fitting opens under traffic. Tap it home the same way, and check the click profile is not damaged before closing it up.
- Fix the floor that keeps drifting. If whole rows wander, the raft has room it should not have or a slope it slides down; refit the perimeter spacing so the expansion gap is even all round.
If gaps come with creaks and visible movement underfoot, the problem is under the boards, and closing the gaps only pauses it. That one is subfloor flatness, which means lifting boards back to the dip and levelling, as covered in the common laminate mistakes guide.
When is a gap a sign of a bigger problem?
Three patterns say stop patching and investigate:
- A gap that grows month on month regardless of season. Something is pinning or pulling the raft, and it will keep going until the cause is freed.
- Gaps in a long unbroken run. Most manufacturers cap a floating floor at about 10 m in either direction, and a hallway running into two rooms passes that fast. Past the limit, seasonal movement outruns what the joints can absorb, and the fix is a break at a doorway with a threshold transition, not a tighter floor.
- Gaps that shrug off closing. If a joint you tapped home opens again in days, the click profile is likely broken or the board has swollen out of shape. That board wants replacing while matching boards are still available.
How do you stop laminate gaps coming back?
Give the floor the conditions it was designed for: boards acclimatised for 48 hours before fitting, an 8 to 12 mm expansion gap on every side with nothing pinning the raft, indoor humidity held between 40 and 60%, and breaks at doorways before a run reaches its limit. All of those are decisions you can check before the first cut. If you are replacing a floor that gapped, run the room through the laminate calculator for the pack count, and settle the layout before the first cut this time. A floor that went down with even perimeter gaps and a break at each doorway has no reason to open up in January.
Frequently asked questions
- Why is my laminate flooring gapping?
- Two causes cover almost every case: the boards have shrunk because the room's air is drier than when they were laid, usually in the first winter of heating, or the floor is pinned somewhere and cannot move as one piece, so it pulls apart at the weakest joint instead.
- Will gaps in laminate close on their own?
- Seasonal ones usually do. Boards that shrank in dry winter air swell back as humidity returns in spring, and hairline end gaps that appear with the heating season close again without help. A gap that survives a humid summer, or keeps growing, has a mechanical cause that needs fixing.
- Can you fill gaps in laminate flooring with filler?
- No. A floating floor has to keep moving with the seasons, and hard filler or glue in a joint pins it at that point, which creates the next gap or a lifted joint nearby. Close the gap by moving the boards back together and fixing whatever let them drift.
- How do you stop laminate gaps coming back?
- Keep the floor free to move and the room's humidity steady. Free anything pinning the boards, such as nailed skirting or a screwed threshold, keep indoor humidity roughly between 40 and 60%, and hold long runs to the manufacturer's limit with breaks at doorways.