How to Install Vinyl Plank Flooring: Prep, Layout and Cuts

The boxes are stacked in the room and the floor looks like an afternoon of clicking planks together. Where it goes wrong is borrowing someone else’s numbers: the gap at the wall is 1/4 inch in one maker’s installation document and 3/16 inch in another’s, and the narrowest row allowed is 2 inches in one and 3 inches in the next. Below is the job in the order you do it, with three makers’ numbers side by side, so you know which line to look for in your own box’s instructions.

The short answer

Step	What decides it
1. Check the subfloor	Flat within 3/16 inch over 10 feet; carpet up; concrete tested for moisture and pH
2. Underlayment or barrier	Usually no separate pad; a moisture barrier over concrete where the maker asks or the slab tests high
3. Condition the room, then the boxes	Room at living conditions first (48 hours TritonCORE, 5 days CALI); boxes 0 to 24 hours for CALI by collection, Karndean only after extreme temperatures (48 hours is the one period printed); damaged planks set aside
4. Decide before you lay	Direct sun: shade it or glue down (TritonCORE); a 3/8 in gap (Karndean); cabinets in first; an expansion joint at a wet room’s doorway (Karndean); breaks in long runs
5. Plan the rows	Measure across the planks; if the last row falls under the maker’s minimum, cut the first row narrower
6. Lay and lock	Spacers at every wall; end joints at least 8 inches apart (200 mm in one guide); first rows straight
7. Cut around things	Undercut door casings; the maker’s gap around pipes and vents; scribe crooked walls
8. Finish	Spacers out; trim fixed to the wall, never through the floor; doorway gaps covered

The three documents used throughout are the TritonCORE Pro planks’ installation instructions (the planks our home improvement guide used as its example), CALI’s vinyl angle-angle installation guide and Karndean’s rigid core plank and tile guidelines. Each covers only its own planks.

	TritonCORE Pro	CALI vinyl (angle-angle)	Karndean rigid core
Subfloor flatness	3/16 in per 10 ft radius	3/16 in per 10 ft radius	3/16 in below level over 10 ft, any direction
Concrete moisture limit	Up to 8 lb per 1,000 sq ft per 24 h, or up to 90% RH; pH 7 to 9	Under 5 lb per 1,000 sq ft per 24 h, or under 90% RH; pH 5.0 to 9.0	8 lb per 1,000 sq ft per 24 h, or 95% RH (Korlok Select)
Wood subfloor	3/4 in plywood or 23/32 in OSB	Moisture no higher than 13%	Moisture not over 13%
Room before install	65 to 85°F for 48 h before, during and after	Year-round living conditions for at least 5 days	No residential hold time given
Boxes	No separate box time; stored flat	24 h unopened for Legends, Laguna, Trestles, Longboards Icons; none for Longboards, All-Star, SP1 unless stored in extreme temperatures	Generally not essential if the planks are already at 65 to 85°F; required after extreme temperatures (the section’s only printed period is 48 h)
Gap at walls and fixed objects	At least 1/4 in	3/8 in or 1/4 in, by collection	At least 3/16 in; 5/16 in over 1,000 sq ft
Narrowest first or last row	2 in	3 in	No number: cut the first row if the last would be narrow
End-joint stagger	At least 8 in	At least 8 in	At least 200 mm

Is your subfloor ready for vinyl planks?

All three want a clean subfloor that is flat within 3/16 inch over 10 feet (for Karndean, 3/16 inch below the level over 10 feet in any direction). What sits under the planks matters as much as how flat it is.

What has to come up. Carpet comes up for the TritonCORE and Karndean planks, and it is not on CALI’s list of acceptable subfloors (our reading). TritonCORE planks also don’t go over plank floors, cushion-backed vinyl, asphalt-based floors, self-adhering (peel-and-stick) plank or tile, laminate or other floating floors, or structurally damaged concrete. For Karndean planks, floating floors and cushion-backed flooring are not suitable substrates and must be removed.

Old resilient flooring or adhesive. Old vinyl tile, sheet flooring and old adhesive may contain asbestos fibers or crystalline silica, so avoid creating dust when you take them up: breathing it is a cancer and respiratory tract hazard, and local regulations may require professional removal (TritonCORE document). Before a Karndean floor, asbestos and asbestos adhesive residue must be mechanically abated by a professional abatement company, and floors laid with asphaltic “cutback” adhesive must first be covered or encapsulated, or mechanically removed.

Concrete. Test it for moisture and pH before you start; the limits differ by maker (see the table). For CALI planks, concrete must be fully cured and at least 60 days old, preferably 90, and free of hydrostatic pressure; three tests should be conducted for an area up to 1,000 square feet, plus one more for each additional 1,000. For TritonCORE planks: if moisture is present, do not install until it is corrected, and do not install when hydrostatic pressure or alkaline conditions are evident. For CALI and Karndean planks, a slab over the limit needs a moisture barrier or membrane.

Plywood or OSB. TritonCORE planks should go over at least 3/4 inch plywood or 23/32 inch OSB, with loose panels, squeaks and raised fasteners fixed first. Under CALI planks, nailing or screwing every 6 inches along the joists is a best practice against squeaks, and the plywood should read 13% moisture or less on a meter; Karndean’s limit for wood subfloors is also 13%.

Existing tile or sheet vinyl. TritonCORE planks can go over ceramic tile, marble, quarry tile or terrazzo that is sound and flat, or over one layer of non-cushioned sheet vinyl in good condition that was glued down over its whole surface and is properly secured, though removing the old floor may be best (if you take it up, see the asbestos and silica caution above). CALI planks accept ceramic tile with the grout lines filled with a compatible patch compound, and resilient tile and sheet vinyl for floating installs. Under Karndean planks, loose tiles are fixed and grout lines wider or deeper than 3/16 inch leveled, and existing linoleum, vinyl or cork floors must be solid, with loose or broken areas fixed.

Low spots and gaps. Grind or sand high spots and fill low ones: only cement-based patch for TritonCORE planks, Portland-based leveling compound for CALI planks. Patch has its own cure time; check it on the bag before you plan the install day.

Do you need underlayment or a vapor barrier?

Usually not a separate pad. A separate underlay is not normally recommended for Karndean rigid core planks; CALI vinyl takes no underlayment over 2 mm; TritonCORE Pro planks come with a 1 mm cork underlayment attached.

A moisture barrier is a separate question. For TritonCORE planks, a barrier is recommended under the floor over a concrete subfloor and required in a crawl space. For CALI planks, a barrier goes down when the slab tests over its limits (the checklist names 6 mil plastic or CALI Complete), and a crawl space needs 6 mil polyethylene over any exposed earth. For Karndean planks, a damp-proof membrane or moisture suppression system is required above its limits. The planks themselves don’t stop moisture: the TritonCORE planks are not a moisture barrier, and with excessive moisture present, mold or mildew growth under them is probable.

How long do the room and the planks need to settle?

Two different waits: the room first, then the boxes.

• The room. For TritonCORE planks, heating and air conditioning run at 65 to 85°F for 48 hours before, during and after installation. For CALI planks, room temperature and humidity must match year-round living conditions for at least 5 days before installation.
• The boxes. CALI Legends, Laguna, Trestles and Longboards Icons sit unopened, as close to the room as possible and out of direct sunlight, for at least 24 hours; Longboards, All-Star and SP1 need no acclimation unless they were stored in extreme temperatures, in which case they get 24 hours in normal living conditions. For Karndean planks in a home, acclimation is generally not essential if they are already at 65 to 85°F, and it is required after extreme temperatures; the period that section prints is 48 hours. TritonCORE boxes are stored flat, never on their sides.

Once the boxes have had their wait (unopened, for those four CALI collections), inspect the planks for visible defects and damage as you open each box to lay; all three documents put that check on the installer, and damaged TritonCORE planks are not to be installed. Plan to mix planks from several boxes as you lay, which all three ask for, so one box’s shading doesn’t end up in one patch of floor. TritonCORE planks should all come from the same production run; check the run numbers on the boxes (our suggestion).

What do you have to decide before the first row?

These change how or where you lay the floor, so settle them now:

• Direct sun. TritonCORE planks in a room that can’t be shaded with UV film, blinds, curtains or shades are required to be glued down, which this floating method doesn’t cover. Karndean planks in sunrooms and other rooms with big temperature swings get a minimum gap of 3/8 inch instead of 3/16.
• Cabinets and islands go in first. No cabinets or kitchen island on a floating TritonCORE floor, no CALI flooring under permanent or fixed cabinetry, and permanent fixtures installed before a Karndean floor, with the expansion gap left around them.
• Bathrooms and laundry rooms. Karndean rigid core planks are suitable for traditional residential bathrooms, kitchens and laundry or utility rooms, not rooms that will be continually wet. In a potential wet area, the gap between fixed furniture and the floor may be sealed with flexible acrylic or flexible low-modulus neutral-cure silicone, but sealant is not for filling expansion gaps in general; the wet room is isolated from the main floor with an expansion joint at the doorway, and the guide recommends a maximum net sealed area of 43 square feet.
• Long runs. A Karndean run over 50 feet gets a 5/16 inch expansion joint, repeated thereafter. CALI WPC flooring such as Laguna, Legends or Trestles gets a 3/4 inch expansion space over 50 feet, and every CALI vinyl collection needs transition pieces past 80 feet in any direction.
• Hot spots. Heating units or non-insulated ductwork close to the floor or subfloor may cause hot spots, which must be eliminated before CALI flooring goes down.
• Stairs. Stairs are glued, not floated, for TritonCORE and Karndean planks, and CALI sells glued stair treads; they are outside this guide.

This is also when you set your spacers to your maker’s gap (see the table).

How do you plan the layout so the last row isn’t a sliver?

Pick the direction. TritonCORE planks are recommended to run perpendicular to the floor joists; CALI planks go along the longest straight exterior-facing wall whenever possible.

Do the row arithmetic before the first plank. Measure the room at a right angle to the plank direction, take off the gap at both walls, and divide by the plank’s face width, the part that shows once two planks are locked (measure a locked pair rather than trusting the box; our suggestion). What is left over is your last row. The minimum is 2 inches for TritonCORE planks, not counting the tongue, and 3 inches for the first and last rows of CALI planks; for Karndean planks there is no number, only the rule to cut the first row if the last would be narrow.

A worked example (our arithmetic): a room 11 feet 4 inches across is 136 inches; with a 1/4 inch gap each side that leaves 135.5 inches. With 7 inch planks, 19 full rows take 133 inches and leave a last row of 2.5 inches. That clears the TritonCORE planks’ 2 inch minimum but not CALI’s 3 inches. To fix it, split the 7 inches of the first row plus the 2.5 inch leftover between the first and last rows: two rows of 4.75 inches, with 18 full rows between them.

Get the room ready. Take off the existing baseboards and moldings, and undercut the door casings (see the door section below) before you snap a line, so nothing stops a row halfway.

Snap a working line. Measure out from the starting wall at both ends and snap a chalk line at a plank’s width plus the 1/4 inch gap (TritonCORE document); if you have cut the first row down, use that row’s width (our reading), so 5 inches for the 4.75 inch row above (our arithmetic). If the wall is out of square, you may need to scribe the first row to the wall so the working line stays straight (same document).

How do you lay and lock the rows?

Tools. Tape measure, pencil, chalk line, square, utility knife and straight edge, spacers, a saw (see Cutting below), tapping block, pull bar and rubber mallet, a drill and spade bit for pipes (Karndean’s list), safety glasses, and soft-cap knee pads only, since hard caps can scratch TritonCORE planks. For vent openings, a jigsaw, and for door casings, a jamb saw or flush-cut handsaw (both our suggestion).

Check the lock. The locking system is printed on the outside of a Karndean box, because the steps differ by system. On a fold-down lock such as Karndean’s 5G, the long side goes in at about 30 degrees, then the short end drops into place and is rubbed over with your thumb or a small roller until it clicks.

Steps, from the TritonCORE document unless another maker is named. Pipes, vents and door frames are cut as their rows reach them; see the next section.

1. Start at the left of the starting wall with the tongue side facing the wall, and work to the right. If you ripped the first row narrower, its cut edge goes to the wall (Karndean’s guide: “tongue side/cut edge facing the wall”).
2. Put spacers between the planks and the wall on the long and short sides, including one where two planks join. Leave the same gap where the floor meets tile at a doorway (CALI lists tile among the fixed objects that get the gap), and where it meets another floor (our suggestion).
3. Lock each plank’s end into the one before it (on CALI’s angle-angle planks, the end goes in at a 45 degree angle and is pushed down) and finish the first row of full planks.
4. Measure from the last full plank to the wall, take off the gap, and cut the last plank to that. If it comes out under 8 inches, cut the row’s first plank shorter instead; the first and last plank of each row stay at least 8 inches long. Before you start row 2, check the long and short seams of the first row for gaps, and if you notice any, stop and reinstall the boards for a snug fit (CALI’s guide).
5. Start the next row with the offcut if it is at least 8 inches long (longer than 8 inches for CALI); on CALI planks, angle the first board’s long side up slightly, push it forward and lock it into the row before. Keep end joints at least 8 inches apart from row to row (at least 200 mm for Karndean, just under 8 inches by our arithmetic), and vary the starter piece so the joints don’t line up in an H pattern (CALI’s guide).
6. Second and later planks in a row: engage the long-side tongue fully into the row before, lower the plank to the floor with its end overlapping the previous plank’s end and aligned, then press the end joint down firmly until it snaps. On CALI planks, insert the new plank’s butt end into the previous plank’s end with the two offset by about 1/2 inch, then slightly lift the new plank and push in along the butt seam until the long side is fully engaged; the plank beside it lifts too, and the end seam should stay engaged.
7. Keep the first two rows straight and square; they set the rest of the floor.
8. Close the seams. A tapping block along the long side may help engage the lock on CALI planks; a pull bar closes the last plank of a row against the wall. On Karndean planks, a mallet is used only if necessary, on an offcut of plank. For fold-and-tap planks, press the seam first, then tap about 1/2 to 1 inch away from it on the tongue side, never on the seam itself, which can break the lock, per one maker’s technical bulletin for its fold-and-tap planks.
9. The last row along the far wall may need to be ripped lengthwise to width and engaged with the pull bar (CALI’s guide). Measure that width at several points and take off the gap, in case the wall is not straight (our suggestion).

Cutting. Check what your document allows: a power saw with at least a 40-tooth blade for TritonCORE planks; score-and-snap with a utility knife for end cuts and a table or miter saw for lengthwise rips on CALI vinyl, per its cutting tips; a knife and straight edge for each row’s last piece on Karndean planks. Wear safety glasses either way.

How do you cut around door jambs, pipes, vents and crooked walls?

Door jambs and casings. Undercut the door casings so the floor slides under them with its gap instead of being cut around them: to the thickness of the flooring for TritonCORE planks, and to provide adequate expansion space for CALI planks; for Karndean planks, door frames are either undercut or left with an expansion gap. One way to do it (our suggestion): lay a plank upside down on the subfloor against the casing as a height guide and saw the casing off flat on top of it with a jamb saw or a flush-cut handsaw. Where a Karndean plank can’t be lifted to angle it in under the frame, tap it together flat on the floor with a tapping block cut from an offcut and a mallet.

Pipes. Find the hole’s position before the plank goes down: measure from the last installed row and from the end of the previous plank (or the side wall) to the pipe’s center, and transfer both measurements to the plank (our suggestion). For CALI planks, drill the hole 3/4 inch larger than the pipe’s diameter, which leaves 3/8 inch all round (our arithmetic); for Karndean planks, the minimum 3/16 inch gap applies at pipes too, cut with a drill and spade bit. Then make two parallel cuts from the sides of the hole to the plank’s long edge on the side away from the installed rows, and lift out that strip; lock the plank in around the pipe and set the strip back in behind the pipe. Its cut edges no longer lock, so glue the strip’s cut edges to the plank, never to the subfloor (our suggestion).

Floor vents. The three documents don’t cover cutting around floor registers. Our suggestion: lift the register cover out; when each plank that crosses it comes up, measure from the last installed row and from the side wall to the edges of the duct, transfer those to the plank, and cut the opening before you lock it in. Make the opening the duct size plus your maker’s gap on each side, still small enough for the register’s rim to cover.

Crooked walls and corners. Scribe the first row to an out-of-square wall (TritonCORE document); for outside corners or complex shapes, mark the shape on the plank and cut it with a saw (Karndean’s guide).

How do you finish the edges and doorways?

1. Take out all the spacers.
2. Fit baseboard or quarter-round wide enough to cover the gap, and fasten it to the wall, never through the floor (TritonCORE document). For Karndean planks, leave a 0.5 mm clearance between the trim and the floor surface; for CALI planks, trim must not be installed tight to the flooring.
3. Doorways (our suggestion): where the new floor meets carpet, tile or another floor, keep your maker’s gap at the threshold and cover it with a transition strip that is not fastened through the planks, since nothing is nailed or screwed through a floated CALI floor. At a wet room’s doorway, that gap is where Karndean’s expansion joint goes.
4. Move heavy furniture and appliances back over plywood laid on the floor, and put floor protectors under the legs (TritonCORE document). Furniture of 500 pounds or more may stop a floating CALI floor from moving freely. On a CALI floor, rugs need a breathable backing; our area rugs guide covers sizes.

After the install, a TritonCORE room stays at 65 to 85°F and 40% to 70% relative humidity.

More flooring, paint and wallpaper how-tos are in our home improvement guides.

Where these numbers come from

The numbers above come from the TritonCORE Pro installation instructions and product page, CALI’s vinyl angle-angle guide, stair tread sheet and cutting tips, Karndean’s rigid core guidelines and one fold-and-tap technical bulletin, all read on 11 October 2026. The room width is our example, and the row widths are our arithmetic.

Frequently asked questions

Do you need underlayment under vinyl plank flooring?

Usually not a separate one: a separate underlay is not normally recommended for Karndean rigid core planks, CALI vinyl takes no underlayment over 2 mm, and TritonCORE Pro planks come with cork attached. A moisture barrier over concrete is separate: recommended for TritonCORE planks, and needed for CALI and Karndean planks when the slab tests over their limits.

Can you install vinyl plank flooring over tile?

For all three makers' planks here, yes, if the tile is sound and flat within 3/16 inch over 10 feet. CALI planks need the grout lines filled with a compatible patch compound; Karndean planks need loose tiles fixed and grout lines wider or deeper than 3/16 inch leveled. Self-adhering (peel-and-stick) tile is on the TritonCORE document's list of floors not to cover. Check your own planks' instructions.

How big a gap do you leave around vinyl plank flooring?

It depends on the planks: at least 1/4 inch for TritonCORE; 1/4 or 3/8 inch by collection for CALI; at least 3/16 inch for Karndean, rising to 5/16 inch over 1,000 square feet and 3/8 inch in sunrooms. The same gap goes around pipes, cabinets and every other fixed object, and baseboard or quarter-round covers it.

Which way should vinyl plank flooring run?

TritonCORE planks are recommended to run perpendicular to the floor joists; CALI planks go along the longest straight exterior-facing wall whenever possible. Whichever way you choose, measure the room across the planks before you start, so the first and last rows are not slivers.

Can vinyl plank flooring go in a bathroom?

Karndean rigid core planks are suitable for traditional residential bathrooms, kitchens and laundry rooms, but not rooms that will be continually wet; plan the expansion joint at the doorway that its guide asks for.