Expansion Gaps: How Much Room a Floor Needs
Laminate 8 to 12 mm at every wall, rigid vinyl at least 1.5 mm per metre of floor, wood about its own thickness: the published figures, and doorways.
An expansion gap is the space left between a floor and every wall, pipe and door frame around it. It looks like a mistake and it is not one: it is the room the floor needs to move. Most of our range needs one. The 36 rigid vinyl floors and the 5 laminates click together and float, and engineered oak can be floated where its fitting instructions allow it. This guide sets out why the gap is there, the published figures for each kind of floor, and how it is hidden.
On this page
Work out your gap
The published figure depends on the kind of floor. Put in your room and the calculator applies it; the table is the same rule written out.
| Floor | Gap at the walls | Long rooms and doorways | Who says so |
|---|---|---|---|
| Laminate | 8 to 12 mm on all sides | A profile in each doorway, and in floors longer than 12 m along the planks or wider than 8 m across them | EPLF |
| Rigid vinyl (click) | At least 1.5 mm per running metre of floor, on each side | Profiles in doorways between rooms | MMFA |
| Floating wood | About the thickness of the board | Transition pieces at narrow doorways | NWFA, unless the maker says otherwise |
| Glued floor | Amtico glue-down LVT: none, says Amtico; glued wood: as its fitting instructions say | – | Amtico |
About 14 mm at every wall
The NWFA puts the gap for a floating wood floor at about the thickness of the board, unless the maker says otherwise.
The figure in your floor's fitting instructions comes first.
Everything here works in your browser; nothing is sent. The sources are quoted in full further down this guide.
Why a floor needs room
Wood and wood-based boards change size with the moisture in the air. The Wood Handbook of the US Forest Products Laboratory says wood swells as it gains moisture and shrinks as it loses it, that this shrinking and swelling can lead to gaps in flooring among other problems, and that wood moves most across the grain and only slightly along it. A floating floor moves as one sheet, so the movement of the whole room adds up at the edges.
The Handbook also says that, in general, no significant dimensional changes will occur if wood is installed at a moisture content corresponding to the average conditions it will be exposed to. That is why boards acclimatise before they are laid. The gap is for the movement that remains, season by season.
Rigid vinyl moves too. The MMFA, the association for multilayer modular floors, says these floors expand and contract due to changes in ambient temperature or humidity conditions, and that they should only be laid as a floating installation.
How much to leave
The figure in your instructions comes first
All of these are general figures. The EPLF itself notes that manufacturers' recommendations vary greatly and that the installation instructions for the product in question should be carefully heeded, and the NWFA's rule applies unless the flooring manufacturer directs otherwise. When the fitting instructions of your floor give a figure, that is the figure to use.
Doorways and long rooms
A floating floor that runs from room to room is squeezed at the narrowest point, the doorway. The EPLF puts expansion joint profiles in doorways between rooms, and on laminate floors longer than 12 m along the planks or wider than 8 m across them. The MMFA says expansion gap profiles generally belong in doorways between rooms, with suitable expansion mouldings with sufficient clearance where different floor coverings meet. The NWFA builds transition pieces into a floating wood floor at narrow doorways. In a doorway, the door bar is where the gap goes.
Hiding the gap
The gap is covered, not filled. The Contract Flooring Association says the skirting can be used to conceal the expansion gap at the floor perimeter, and that timber skirtings should only be fixed to the wall, so as not to restrict any expansion of the floor finish. The MMFA says the gaps can easily be covered with corresponding plinths, and the NWFA says trim pieces should never be fastened to or through the flooring system. Where the old skirting stays in place, a beading along its foot does the same job, fixed to the skirting rather than to the floor.
What goes wrong without it
A floating floor that is pinned cannot move as one sheet. A wall, a door frame, a kitchen unit standing on the floor or a skirting fixed down through it are the usual culprits, and the movement then goes upwards: the floor lifts or the joints open. In a kitchen, a floating floor runs under the kick boards rather than under the units for the same reason.
Common questions
How big should an expansion gap be?
For laminate the EPLF recommends 8 mm to 12 mm on all sides. For rigid vinyl the MMFA's rule of thumb is at least 1.5 mm per running metre of floor on each side. For a floating wood floor the NWFA puts it at about the thickness of the board. The figure in your floor's fitting instructions comes first.
Does a glued floor need an expansion gap?
Not in the same way. Amtico says its adhesive bonded LVT needs no expansion gap or silicone sealant. For a glued wood floor, the board's fitting instructions say what it needs at the edges.
Do I need a door bar between rooms?
For a floating floor, usually yes. The EPLF and the MMFA both put expansion profiles in doorways between rooms. The guide to door bars and thresholds covers the profiles themselves.
Can skirting boards cover the expansion gap?
Yes. The Contract Flooring Association says the skirting can conceal the gap, and that timber skirting should only be fixed to the wall, so it does not restrict the floor.
Does every floor need the same gap?
No. Laminate, rigid vinyl and floating wood each have their own published figure, and a glued floor follows its instructions. Long rooms also need more: the EPLF puts a profile in a laminate floor longer than 12 m along the planks or wider than 8 m across them.
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What the published standards say
Who publishes this guide
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