Planning the first and last row: how to avoid sliver cuts

The first row's width decides the last row's width; they are one decision, not two. Divide the room width by the board width, look at the remainder, and split it so both edge rows stay healthy. Do this before laying board one, because by the time the problem is visible, the whole floor is between you and the fix.

The arithmetic

1. Measure the room width (the direction across the boards), subtract both expansion gaps.
2. Divide by the board width. The whole number is your full rows; the remainder is what's left for the last row.
3. If the remainder is comfortable (more than ⅓ of a board): lay the first row full, last row takes the remainder. Done.
4. If the remainder is a sliver (less than about 50 to 100 mm): rip the first row down so the leftover moves into it. Split the remainder plus one board width across the two edge rows, ideally equally, so the room reads symmetric.

Example: room 3.42 m, gaps 2 × 10 mm → 3.40 m laying width. Boards 192 mm wide: 3400 ÷ 192 = 17 rows + 136 mm remainder. 136 mm is legal but mean. Better: 17 full rows is 3264 mm, remainder plus one board = 328 mm; rip first and last rows to 164 mm each. Symmetric, solid, and no sliver against either wall.

Why slivers actually fail

• Mechanically: ripping a board removes the locking profile on one edge; a 30 mm strip is held by almost nothing and flexes underfoot until it creaks or snaps.
• Visually: a skinny strip along a wall reads as a measuring mistake, because it is one. Worse when the wall is slightly out of true, since a 30 mm strip makes a 5 mm taper obvious; a 160 mm strip absorbs it.
• At doorways: edge rows land in traffic. This is where sliver rows break first.

If you're reading this after laying, with the floor down and a 40 mm gap left, the recovery options are in the last row is too thin.

Walls that aren't straight

Measure the room width at both ends (and the middle, in old houses). If they differ by more than a few millimetres, the first row must be tapered, scribed to the wall, so every later row runs straight. The taper hides under the skirting; the alternative, a tapered last row in full view, advertises it. The measuring guide covers how to check.

This is a solved problem, so let arithmetic do it

Every rule above is arithmetic on the room width, board width, gap and minimum widths. It's exactly what the designer computes when it lays out a room, including the ugly cases (L-shapes where two zones want different splits, obstacles that interrupt rows, patterns whose stagger interacts with the starters). The layout preview shows the first and last row widths before you buy a board, which turns this whole guide into a checkbox.