Key takeaways
- The five vinyl plank installation sheets we read ask for a perimeter gap from 1/4 inch to 1/2 inch, so your product's sheet decides.
- Their limits on a run before a transition range from 25 feet to 80 feet, and two of them want a T-molding in any doorway under 6 feet wide.
- Quarter round pieces = trim length ÷ stock length, rounded up, and counting wall by wall shows where the joints fall.
A floating floor isn't fastened down, so it can grow and shrink with the room. It needs a gap at every wall and fixed object, and some rooms need a break in the floor. Your product's installation sheet sets these figures, and following it usually matters for the warranty. This page shows how much the sheets differ and how to plan the trim.
Why floating floors move
Planks expand and contract as temperature and humidity change through the year. ELEME's installation guide puts this at up to 2 mm per meter (1/12 inch per 3.28 feet), so a bigger room needs more room to move.
A floor that's pinned at its edges has nowhere to go. The sheets we read all warn about this. Typical causes are a gap that's too tight, trim nailed through the floor, or a kitchen island set on top of it. The result is buckling, peaking at the joints, or gaps opening between planks.
What five installation sheets say
We read five vinyl plank sheets. They don't agree, which is the main point:
| Product sheet | Perimeter gap | Run before a break | Doorways | Acclimation |
|---|---|---|---|---|
| Xulon Luxury Vinyl Click | 1/4 in | Every 30 ft in either direction | T-molding, as doorways are under 6 ft | At least 48 hours |
| Dotfloor Empire Collection | At least 1/4 in | Large runs may need more space (no figure) | Transitions at doorways 3 ft or less | 1 to 2 days |
| Montserrat vinyl plank | 1/4 in | Over 80 ft long or wide | No figure given | 48 hours |
| STAINMASTER locking vinyl | 5/16 in | No figure in the text we read | T-molding in openings under 6 ft | 24 to 48 hours at 71°F |
| ELEME vinyl plank | 3/8 in minimum; 5/16 to 1/2 in along each wall | Over 25 ft wide or 30 ft long | Expansion joint with a T-molding | 48 hours at 18 to 22°C |
So the figure on most sheets we read is 1/4 inch, and the range across them is 1/4 to 1/2 inch. These are all vinyl plank. Laminate and engineered wood sheets set their own figures, so don't borrow these for those floors.
Where you need a transition
A transition strip breaks the floor into separate pieces that move on their own. The sheets we read call for one in three situations:
- Long runs. Depending on the sheet, past 25 to 30 feet, or 80 feet. One sheet gives no figure.
- Doorways. Xulon and STAINMASTER want a T-molding in any opening under 6 feet wide. Dotfloor uses 3 feet or less.
- A change of floor. Where the floor meets a different floor or height.
Measure the whole run of continuous floor, not one room at a time. A hallway joining two rooms with no break is one long run.
The trims and what they do
Xulon's sheet describes the common pieces:
| Trim | Where it goes |
|---|---|
| Quarter round or baseboard | Covers the gap at walls and fixed objects |
| T-molding | Joins two floors of similar height |
| Reducer | Steps down to a lower floor |
| End cap | Finishes the edge at sliding doors, tubs and similar spots |
| Stair nose | Finishes exposed edges of steps and landings |
Fasten trim to the wall or the subfloor, never through the floating floor. Xulon, STAINMASTER and Montserrat all say so. STAINMASTER also says to set moldings at least 1/32 inch above the floor so it can slide underneath. Undercut door jambs so planks can slide under them with the gap kept.
Cabinets and kitchen islands can't go on top of a floating floor on any of the sheets we read. Install them first and float the floor up to them, leaving the gap.
Acclimation
The sheets above ask for 24 to 48 hours or more, with the boxes in the room where they'll be installed. Most want the heating or cooling running at normal living temperatures before, during and after installation. Store boxes flat, follow the temperature range on your sheet, and keep them out of direct sun.
Worked example
A 12 × 15 foot room with two 3-foot doorways, one on each long wall. Each opens into a room with the same new floor.
How much the floor might move: 15 feet is 4.57 meters. At ELEME's figure of up to 2 mm per meter, that's 4.57 × 2 = 9.1 mm, about 3/8 inch across the room. Split between the two end walls, that's about 4.6 mm each. A 1/4-inch gap is 6.35 mm, so it leaves room on a sheet that asks for it.
Transitions: the room's longest run is 15 feet, under every limit in the table. But both doorways are 3 feet wide, under the 6-foot figure on two sheets and within Dotfloor's 3-foot figure. So plan two T-moldings, one per doorway.
Quarter round: the perimeter is 2 × (12 + 15) = 54 feet. Take off the two doorways: 54 − 6 = 48 feet. Say your store sells 8-foot lengths:
- Total method: 48 ÷ 8 = 6 pieces
- Wall by wall: each wall is now a 12-foot run. That takes one 8-foot piece plus 4 feet. The 4-foot offcut from one wall finishes the next, so 6 pieces still works, with a joint on every wall.
If your store sells longer lengths, each wall could be one piece. Corners are mitered, so a spare piece covers a miscut. The baseboard and trim calculator does the same count for baseboard and shoe molding, and the flooring calculator counts the boxes.
Common mistakes
- Using one gap figure for every product. The sheets we read range from 1/4 to 1/2 inch.
- Measuring room by room. A floor that runs through doorways with no break counts as one run.
- Nailing quarter round into the floor. It pins the edge. The sheets say to fasten trim to the wall.
- Setting heavy, fixed things on top. Cabinets and islands go in first.
- Skipping acclimation. Every sheet we read asks for at least a day.
Frequently asked questions
How big an expansion gap does vinyl plank need?
Commonly 1/4 inch, but the five sheets we read range from 1/4 to 1/2 inch. Use the figure on your product's sheet.
Do I need a transition strip in every doorway?
On some products, yes. Xulon and STAINMASTER want a T-molding in openings under 6 feet wide. Check your sheet, as others differ.
How long can a floating floor run without a transition?
It depends on the product. The sheets we read gave figures from 25 to 30 feet up to 80 feet, and one gave none.
Can baseboard cover the expansion gap?
Yes, if it covers the gap fully and isn't fastened through the floor. Quarter round over existing baseboard is the usual alternative.
How long should vinyl plank acclimate?
The sheets we read ask for 24 to 48 hours or more in the room, with normal heating or cooling running.
Can I put a kitchen island on a floating floor?
None of the sheets we read allow it. Install fixed cabinets and islands first, then float the floor up to them with the gap.
Sources
We use primary sources where we can: building codes, federal rules and manufacturer documents. Read our editorial standards.
- Xulon: Luxury Vinyl Planks Click installation guide
- Dotfloor: Empire Collection installation guide
- Montserrat Floors: Vinyl plank installation guide
- STAINMASTER (Novalis): Floating floor installation instructions
- ELEME Flooring: Installation guide