Short answer: in most rooms, loose lay vinyl planks do not need a perimeter expansion gap. The heavy fibreglass-reinforced backing and high friction grip on the subfloor mean each plank sits where you put it and barely moves with seasonal temperature swings. There are still three situations where you should leave a small gap anyway, and the acclimation step is non-negotiable. Here is how an installer actually decides.
Why click-lock vinyl needs a gap and loose lay usually doesn’t
An expansion gap is the 8-10 mm void around the perimeter of a floor that lets the planks move as humidity and temperature change through the year. With click-lock SPC hybrid or laminate, the whole floor is mechanically locked together — every plank pulls on its neighbour. If even one edge is pinned against a wall, the whole floor pushes against itself when it expands. That is when you see peaking at joints, lifting in the middle of a room, or popped end-locks. The fix is to leave the gap, then cover it with skirting or scotia.
Loose lay vinyl is a different system. Each plank is roughly 4.5-5 mm thick with a heavy fibreglass-reinforced backing and a high-friction underside. There is no click profile and no locking system to compare to 5G and 2G click systems. Planks butt up against each other but are not joined. Friction holds the plank field in place; small movements relieve at the seams between planks rather than pushing on the perimeter. That is why most loose lay manufacturers — Karndean, Polyflor, Gerflor — do not call for a perimeter expansion gap in standard residential rooms.
Three cases where you should still leave a small gap
- Rooms longer than 12 metres in any direction. Cumulative dimensional change adds up over distance. On open-plan layouts that run 12 m-plus end to end, we leave a 5 mm gap at both ends as cheap insurance. Skirting hides it.
- Direct sun on dark planks. A very dark floor under big northerly windows can sit at 50-55 degrees on a 38 degree summer day. That is enough movement to be worth a perimeter gap, even on loose lay.
- Heated subfloors. Hydronic or electric in-slab heating cycles the plank temperature daily. Manufacturers’ instructions for heated slabs almost always specify a perimeter gap and a maximum operating temperature (usually 27 degrees at the plank surface). Follow them — it is what protects the warranty.
For the typical 50-90 m² Australian living room or bedroom on a slab or particleboard subfloor, none of these apply and a butt-to-skirting install is fine.
What you absolutely cannot skip: acclimation and subfloor prep
Loose lay forgives a missing expansion gap. It does not forgive a damp slab, a dusty subfloor, or planks that were unloaded straight off a cold truck and laid that afternoon.
- Acclimate for 48 hours. Bring the planks into the room they will be installed in, lay the boxes flat, and leave them for two days. Room temperature should be between 18 and 27 degrees. This is the same range you will live in, so the planks are at their installed dimension when they go down.
- Check subfloor moisture. Concrete slabs need to read under 75% RH on an in-situ probe (or the equivalent on a hood test). A damp slab will not damage the loose lay vinyl itself, but it will trap moisture under the floor and grow mould.
- Get the subfloor flat. The standard for vinyl is 3 mm variation over a 3 m straightedge. Loose lay shows every dip and bump because the planks conform to the surface. Self-levelling compound or floor patch fixes most cases. Our notes on how to lay vinyl on a concrete floor walk through prep step by step.
- Underlay is rarely needed. Loose lay relies on direct contact with the subfloor for friction grip, so adding a soft underlay defeats the system. See the underlay for vinyl flooring guide for when underlay is and is not appropriate.
Perimeter tackifier — the middle ground
For rooms where you want extra hold without going to a full glue-down, a 200-300 mm band of pressure-sensitive tackifier around the perimeter (and around any kitchen island or fixed cabinetry) is the trade standard. The field of the floor is still loose-laid; only the edges are bonded. This is what we do in commercial fitouts and high-traffic residential entries. It is overkill in a normal bedroom.
Quick install checklist
- Acclimate planks 48 hours in the install room, between 18-27 degrees.
- Confirm subfloor is dry, clean and flat to 3 mm in 3 m.
- Skip the perimeter gap unless the room runs over 12 m, has dark planks under direct sun, or sits on a heated slab.
- Use perimeter tackifier in commercial spaces and high-traffic residential layouts.
- Check the manufacturer’s installation guide before you cut the first plank — it overrides the general rule for that specific product.
The bottom line
Loose lay vinyl is one of the few floors you can take right up to the skirting in a normal-sized room. The friction backing does the work the click-lock joint does on a hybrid floor. Acclimate it properly, prep the subfloor flat and dry, and it will sit tight for the life of the floor. If you are weighing loose lay against click-lock SPC for a kitchen, laundry or wet area, our waterproof flooring options guide walks through the tradeoffs. Pop into our Sydney or Brisbane showrooms if you want to handle the Karndean and Polyflor loose lay ranges in person before deciding.