How to Replace One Plank in the Middle of a Floating Floor

Why this matters

A gouged or swollen plank twelve rows from the nearest wall is a problem the floor was never designed to solve. The joints lock each plank to the row before it, so the textbook repair is to take the floor apart from the wall back to the damage, which in the middle of a kitchen can mean lifting under an island, a range and a dining table to replace one board. The alternative is to cut the damaged plank out in place and drop a modified replacement in with glue. Done well, nobody finds it. Done badly, the saw kerf runs into the neighbor, the replacement sits proud by a sixteenth, and the shop now owns two damaged planks instead of one.

This card covers the cut-out and the call between cutting out and taking apart. How the joints lock is in Click-Lock Flooring Joints: Angle, Drop and Fold, and the full disassembly is How to Lift and Relay a Click-Lock Floating Floor.

The gate: cut it out, or take it apart

Count rows to the nearest wall the floor releases from, and look at what sits on those rows. A shop default: three rows or fewer to a release wall, with nothing heavy or built in on them, take it apart. More than three rows, or a cabinet, island or appliance on the rows in between, cut it out.

The reasoning runs both ways. Disassembly keeps every factory joint, uses no glue, and leaves a floor that can come apart again later. Cut-out loses the locking profile on the replacement for good, puts glue in three or four joints, and cannot be undone without cutting again. So disassembly wins whenever it is cheap. It stops being cheap in proportion to the rows and the furniture between you and the wall, and a glued plank in the middle of a room is a fair trade for not lifting under a set of cabinets. Floors under a warranty claim are a third case: some makers will not honor a claim on a floor with a glued repair, so read the warranty before cutting.

The cut, drawn

 DAMAGED PLANK, SEEN FROM ABOVE (not to scale)

 +--------------------------------------------+
 | \                                        / |
 |  \ relief cut, corner to corner        /   |
 |   +-----------------------------------+    |
 |   |  inner plunge cut, about 1 in in  |    |
 |   |  from every edge; center lifts    |    |
 |   |  out first                        |    |
 |   +-----------------------------------+    |
 |  /                                     \   |
 | /    edge strips stay until last        \  |
 +--------------------------------------------+

 REPLACEMENT PLANK, END VIEW ACROSS ITS WIDTH

  kept tongue               groove, lower lip cut off
     |                             |
     v                             v
  ==[=============================   <- face
     =============================]  <- lower lip cut
  tongue angles into the     drops down over the
  neighbor's groove          neighbor's tongue

The inner cut stops short of the joints so the saw never reaches a neighbor. The relief cuts give each edge strip somewhere to go: once the center is out, each strip is pulled inward toward the hole, which slides its tongue or groove off the neighbor without lifting it.

The steps

1. Get the right replacement before you cut. Leftover boxes from the original job are first choice, a plank pulled from a closet or under an appliance second. Compare face pattern, color and thickness in daylight next to the damaged plank. Reason: a cut-out you cannot fill is a hole in the customer's floor. If you skip it: you have committed to a repair with no part. See related: Why New Material Does Not Match Old Material.

2. Set the blade depth to the plank's thickness and check what is under it. Measure a plank at the wall or at a transition. Set a plunge-capable circular saw or track saw to that depth, never more, and finish corners with an oscillating multi-tool. Ask whether the floor has radiant heat: a thermostat with a floor sensor, or tubing seen in the basement. Reason: the plank is the only thing you are cutting. If you skip it: a blade set deep cuts the pad, the subfloor and anything in it, and radiant tubing or an electric heating mat under a floating floor turns a plank swap into a different trade. Hazard: the cut makes fine fiberboard or mineral-filled vinyl dust; run the saw's dust port to a shop vacuum and wear eye protection, and where your shop's program calls for a respirator for this dust it is worn under a written 29 CFR 1910.134 program. A plunge saw kicks back if it is lowered moving; plant the shoe, start the motor, then plunge.

3. Cut the inner rectangle and lift the center out. Plunge along all four sides about 1 in inside the plank's edges and lift the center piece out. If you skip ahead to cutting near the edges, the blade wanders into the neighbor's locking lip, which is the one thing this repair cannot recover from.

4. Make the relief cuts and pull the edge strips inward. Cut from each inner corner diagonally toward the plank's corner, stopping short of the corner itself, and finish the last half inch with the multi-tool. Pull each strip into the opening. Reason: the strips are still locked to the neighbors, and pulling them toward the hole disengages them without prying up a neighbor's joint. If you skip it: prying a strip up levers against the neighbor's lip and cracks it.

5. Clean and inspect the opening. Vacuum the pad, check it for damage, and look at the four neighbor edges: each tongue and groove should be whole. If a neighbor's lip is cracked, stop and decide whether this is now two planks; do not glue a replacement against a broken edge and hope.

6. Modify the replacement to drop in. Keep the tongue on one long side, the side whose neighbor has an open groove, so you can angle it in. Every other edge has to come down from above. Where that edge would have to slide under a neighbor's lip, cut its tongue off. Where it comes down over a neighbor's tongue, cut the lower lip of its groove off, as drawn. Do it on a bench with a fine-tooth blade or a utility knife and straightedge, and dry-fit. Reason: a locking profile engages by moving sideways or at an angle, and a plank boxed in on four sides can only move straight down. If you skip it: the replacement sits proud, or is forced and cracks.

7. Glue only the modified joints, and weight it. Run the adhesive the flooring maker specifies for repairs along the neighbors' tongues and the modified edges, angle the kept tongue in, fold the plank down, and wipe squeeze-out at once. Weight it evenly, a bucket of water or a stack of boxes on a board spanning the plank, for the time the glue label states, commonly several hours to overnight, with no traffic until then. If you skip it: the plank lifts a hair at the glued edges as it cures, and a raised edge is what a sock or a vacuum catches.

8. Check flush before you leave. Run a fingernail across all four joints. Any lip you can catch is a lip the customer will feel.

Worked example: one gate, two planks

Same house, same laminate, same afternoon. Planks are 8 in wide by 48 in long; the floor runs through a kitchen and into a family room.

Plank one: a gouge by the island. A dropped cast-iron pan cut through the wear layer of a plank in the kitchen. Counting rows from the kitchen's release wall: the plank is in row 9, and rows 3 through 7 run under the island cabinets. Nine rows is past the three-row default, and the island alone would decide it. Gate: cut out.

The tech measured the plank at a transition at 12 mm and set the saw to 12 mm. The inner rectangle ran about 1 in in from the edges, so roughly 46 by 6 in, and came out in one piece. The relief cuts and edge strips came out cleanly, and the pad underneath was undamaged. The replacement, from a box in the garage, kept the tongue on the long side facing the row that had an open groove; the other long side and the groove end had their lower groove lips trimmed, and the tongue on the opposite end was cut off. Dry fit flush. Glued, folded down, weighted with two 5-gallon buckets of water on a 2x6 for the overnight cure the glue label gave. Next morning a fingernail caught nothing on any of the four joints.

Plank two: a swollen edge by the patio door. Water from a door left open in a storm had swollen the end of a plank in the family room. It sat in row 2 from the patio wall, and the patio wall was the finishing wall, so its rows released freely. Nothing sat on rows 1 and 2 but a light chair. Two rows is inside the three-row default with nothing heavy on them. Gate: take it apart.

The tech pulled the quarter round on the patio wall and on the two side walls where rows 1 and 2 ended, lifted row 1 and row 2 by the method in How to Lift and Relay a Click-Lock Floating Floor, and swapped the swollen plank for a full factory plank, whose locking profile was left whole. The tech checked the subfloor under it for moisture against a dry spot elsewhere in the room before relaying: same reading. Relaid, gap kept with spacers, trim back on. No glue anywhere.

Why the two outcomes are right. Plank two could have been cut out too, and it would have looked the same that day. But it would have spent a glued, non-removable repair to save lifting two rows. Plank one could in theory have been reached from the wall, at the cost of lifting under an island. The gate is not about difficulty. It is about which floor the customer has left when you drive away.

What changes the method

• Rigid-core vinyl. It cuts and trims the same way, but many rigid-core makers specify a particular adhesive for repairs, or none, and some publish their own replacement method. Read the instruction sheet first; ordinary flooring glue may not hold on a mineral core.
• Glue-down vinyl plank. Not floating at all. It is released with heat and a scraper and reset in adhesive, which is a different procedure.
• Damage that runs across rows. Two or three damaged planks in a line usually means water or a subfloor problem underneath them. Find that before you replace planks over it.

References

• See related: Click-Lock Flooring Joints: Angle, Drop and Fold
• See related: How to Lift and Relay a Click-Lock Floating Floor
• See related: Invisible, Blended or Acceptable: The Three Grades of Finish Repair
• Flooring manufacturer installation and repair instructions for the specific product