How to Fit the Last Row and Door Jambs When Floating

Why this matters

The last row and the door openings are where a floating floor is most likely to be pinned, gapped or left unlocked, because they are the two places the plank cannot be handled the way the rest of the floor was. The wall leaves no room for a tapping block, the jamb sits on top of the joint you need to engage, and the scribe is the one cut where a 1/8 inch mistake either closes the expansion space or opens a gap the base will not cover. Get the geometry right on paper first; the cutting is then routine.

The geometry, before any steps

The piece you need is the distance from the last full row to the wall, minus the expansion space. Walls are not straight, so that distance changes along the room, and the reliable way to carry it onto the plank is to let the wall draw it.

The standard scribe stacks three planks:

• A is the last full row, locked in place.
• B is the plank you will cut, laid loose exactly on top of A with the face edges lined up, oriented the same way A is.
• C is a full scrap plank laid on top of B, with one face edge pushed against a spacer at the wall equal to the expansion space. Turn it so a face edge, not a tongue, bears on the spacer.

Trace along C's other face edge onto B. The part of B on the room side of the line is your piece. Its width works out to the gap minus the spacer, at every point along the wall, because C is exactly one plank wide. And because B was oriented the same as A, its room-side profile is the one that mates with A's wall-side profile once you slide it over.

At a door in the same wall, the piece also has to run into the opening, out to the edge of the transition gap, so it is wider there and notched where it passes the jambs.

 SECTION, looking along the rows, about 4 chars per inch
 |  C: full plank on top, pushed to a 3/8 in spacer
 |s+-----------------------------+
 |               +---------------+---------------+ B
 |               |    waste      | keep 3-7/8 in |
 |               +---------------+---------------+
 |               +-------------------------------+ A
 |<- G 4-1/4 in ->| A: last full row, locked
 wall          trace line on B = C's room-side edge

 PLAN at the door in the same wall, room below
            T-molding gap edge, 2 in past wall face
               +--------------+
               |   opening    |
 wall face ====+ jamb    jamb +==== wall face
               |              |
 +-------------+              +---------------+
 |  3-7/8 in       6-1/4 in at the door       |
 +--------------------------------------------+
 ========= A: last full row, locked ===========

The job these steps follow

A bedroom finished in 7-1/2 inch rigid core click planks, 3/8 inch expansion space per the maker's sheet, which also states a minimum last-row width of 2 inches and allows the locking lip to be trimmed and the joint glued with a named adhesive where a plank cannot be angled. The gap from row A to the wall reads 4-1/4 inches at the left end and 4-5/8 inches at the right. The bedroom door is in this wall near the left end; a T-molding will sit under the closed door, its gap edge 2 inches past the wall face into the opening. Casings and jambs are already undercut (see related: How to Undercut Door Jambs and Casing).

Step 1: Measure the gap along the whole wall

Read the distance from A to the wall every 2 to 3 feet and at each door. The readings tell you three things: the piece tapers from 3-7/8 to 4-1/4 inches (4-1/4 minus 3/8, and 4-5/8 minus 3/8), both above the 2 inch minimum; nowhere does the wall dip close enough to need a separate piece; and at the door the piece is 4-1/4 plus 2, or 6-1/4 inches, which a 7-1/2 inch plank covers.

Skip it and you scribe a plank, cut it, and find at the door that you needed the wide piece from the plank you just ripped narrow.

Step 2: Scribe each piece in place

Work one plank length at a time. Lay B on A at that position, C on B against the spacer, and trace. Slide C along the wall as you go so it follows every bump. Mark each B on the back with its position (L1, L2, and so on) so the tapered pieces go back where they were drawn.

For the door piece, scribe the full length the same way, then hold it in position and mark the outside face of each jamb on it. Measure from the wall face line out into the opening to the T-molding gap edge, 2 inches here, and add it plus the 3/8 inch expansion space the scribe took off (there is no wall to keep clear of in the opening) to the piece's width between the jamb marks: 3-7/8 + 3/8 + 2 = 6-1/4 inches, matching Step 1.

Step 3: Cut to the line, on the waste side

Cut on the waste side of the line and leave the line on the piece. A saw kerf taken out of the keep side narrows the piece by the kerf, and on a 3-7/8 inch piece that is the difference between a covered gap and a visible one.

For the notch, cut each shoulder so it falls under the jamb, not in the open doorway: the undercut lets the wide section run under the jamb a little, and the step in the piece hides beneath it.

Hazard: score-and-snap where the plank allows it to keep dust down. A saw cut in rigid core or a laminate core throws fine dust; use dust collection and eye protection, and where respirators are required, wear them under a written program per 29 CFR 1910.134 (applied to construction work by 29 CFR 1926.103). A utility knife slips toward the hand that is holding the plank; keep that hand behind the blade's path.

Step 4: Lock the last row with a pull bar

The wall leaves no room for a tapping block, so the last row is drawn tight with a pull bar.

1. Angle each piece's profile into A's edge and lower it, the same as the field. A ripped piece is narrower than the gap, so it tilts in without hitting the wall.
2. Engage end joints between the last-row pieces the way the profile requires (see related: Click-Lock Flooring Joints: Angle, Drop and Fold).
3. Hook the pull bar over the piece's wall-side edge and tap the bar's end lightly with a hammer, working along the plank, until the joint is tight and flat.
4. Reset the 3/8 inch spacers behind each piece. Pulling can drag the piece tight to the wall and close the gap.

Only draw a long joint in flat if the sheet says this profile can be engaged horizontally; forcing a profile built to be angled cracks its locking lip. Read the sheet before you scribe.

Step 5: Fit the door piece flat under the jamb

The jamb sits directly above the joint between the door piece and A, so the piece cannot be lifted to angle it in. It has to go in flat.

1. Read what the maker allows. This sheet allows trimming the lower locking lip off the groove side so the piece can drop flat onto A's tongue, with the joint glued using the adhesive it names. Other sheets allow tapping certain profiles together horizontally. Do only what the sheet says for that product.
2. Trim the lip with a sharp chisel or utility knife, only the length that sits under and between the jambs, and dry-fit. The face must sit level with A's face.
3. Glue the joint with the named adhesive, slide the piece in under the jambs, press it down, and wipe squeeze-out off the face with a damp cloth right away.
4. Hold it with low-tack tape across the joint or a weight until the adhesive sets.

What breaks if skipped: a door piece forced in by bending it under the jamb cracks the core or chips the locking edge, and the joint lifts the first time the door is closed over the T-molding.

A note on undoing it. A glued joint is no longer a click joint. If the door piece is wrong, it is cut out, not unlocked. Mistakes anywhere else in the last rows come out by unlocking back from the wall; see related: How to Lift and Relay a Click-Lock Floating Floor.

Step 6: Plank ends that land under a jamb

On an end wall, the last plank in a row often has its end disappearing under a casing and jamb, with its other end needing to fold down into the plank beside it. If the jamb is in the way of the fold-down:

• Slide the plank in under the jamb first, then draw it back along the row with the pull bar to engage the end, where the profile allows horizontal engagement; or
• Trim the end joint's lower lip and glue it, the same way as Step 5, where the sheet allows.

Either way, the plank's end stops short of the wall framing by the expansion space, hidden under the casing.

How to verify you got this right

• Gap everywhere. A thin putty knife enters behind every last-row piece and under each jamb; the floor is free to move. In the bedroom it entered along the full wall, and the gap read 3/8 inch at both ends.
• Last row flat. Stand and look along the wall in normal light: no lip at the A joint, no piece riding up on a spacer.
• Door piece level and still. Step on both sides of the joint at the door. No movement, no click, no glue on the face.
• Door clears. Swing the door closed over the T-molding position; it must not drag on the floor or the trim.
• Widths match the plan. The narrowest last-row piece measures at least the 2 inch minimum; in the bedroom the narrowest was 3-7/8 inches.

Pull the spacers only after all of this, then install base and shoe nailed into the wall, never the floor (see related: How to Install Baseboard and Shoe Over a New Floor).

References

• The flooring maker's installation instructions (expansion space, minimum last-row width, permitted lip trimming and adhesive)
• 29 CFR 1910.134, respiratory protection, where respirators are worn (29 CFR 1926.103 applies it to construction)
• See related: How to Lift and Relay a Click-Lock Floating Floor
• See related: Click-Lock Flooring Joints: Angle, Drop and Fold
• See related: How to Install Laminate or Rigid Core Floating Floors