Which way to run planks, and how to avoid a thin last row

Choosing the direction

Three things decide which way the planks run, in order of importance.

The joists, for nailed solid wood. Solid hardwood nailed to a plank or plywood subfloor should run across the floor joists, at right angles to them, so each board spans several joists. Running parallel to the joists is possible only with a thicker subfloor or extra blocking. Floating floors and glued engineered wood do not have this constraint.

The longest view. Planks look best running along the longest dimension of the room, or toward the main entrance, so the eye follows them. In a long hallway, run them along the hall; across it, the floor looks like a ladder.

The light. Running planks toward the main window hides the end joints, because the light falls along the boards rather than across their edges. This matters most with bevelled-edge planks.

When the rooms run into each other, keep the direction continuous through the doorways. A change of direction needs a transition strip at the doorway, which a floating floor needs there anyway in a long run.

The last row

The planks run one way, and the room’s width across them is divided into rows. Unless the width happens to be an exact number of planks, the last row is a strip narrower than a plank. Manufacturers ask for at least 2 inches, and many installers aim for half a plank or more, because a thin strip is fragile, hard to fasten and looks like an afterthought.

Two rooms worked through

The plank layout calculator does this for any room and plank, and draws the rows. For an 11 ft room in 5 inch plank it finds 27 rows with both edge rows ripped to 3.125 inches.

Measure in more than one place

Walls are rarely parallel. Measure the room’s width at both ends and in the middle. If the width changes by more than half an inch, the last row will taper. Snap the first row’s line parallel to the longest, most visible wall, and scribe the first row to the starting wall so the line is straight. The taper then ends up at the less visible wall.

Staggering the end joints

End joints in neighbouring rows must be offset, usually by at least 6 to 12 inches depending on the maker. With fixed-length click planks, a simple pattern of thirds gives 16 inch offsets with 48 inch planks. A strict staircase looks mechanical, so vary the start of each row while keeping the minimum offset, and avoid an “H” where end joints in rows one and three line up.

The offcut from the end of one row usually starts the next. That reuse is why straight plank floors need only 10% waste, and the laminate calculator and the vinyl plank calculator use that figure by default.

Doorways, hallways and connected rooms

When the floor runs through several rooms, plan the rows from the longest straight line through the whole area, often a hallway, and let each room take its last row where it falls. Laying room by room from each room’s own wall makes the rows drift out of line at the doorways, and a row that is off by half an inch at a door is impossible to hide.

Snap a chalk line through the doorways first, parallel to the main wall, and measure from it to the far wall of each room. That shows where the narrow rows will fall in every room before the first plank goes down. If one room ends in a sliver, move the starting line by a few inches and check again; the line is free to move until the first row is down.

Floating floors over a long run need a break. Most makers limit a floating floor to 30 to 50 ft in any direction without a transition, and a doorway between rooms is the natural place. The thresholds and transitions calculator counts the strips.

Around obstacles

A floor vent, a pipe or a door casing interrupts a row, not the layout. Undercut door casings with a jamb saw so the plank slides under them; drill pipe holes slightly larger than the pipe for the gap, and cut the plank through the hole so the piece behind can be glued back in place. Plan the row that meets a kitchen island the same way as a wall: if it would end in a sliver, adjust the starting line.

The gap at the walls

Every floating floor and every solid wood floor needs a gap at all walls and fixed objects, hidden later by the baseboard or shoe moulding. The gap is part of the arithmetic for the last row: a 3/8 inch gap at each wall takes 3/4 inch off the width. The expansion gap calculator sets the gap for the floor and room, and the expansion gap guide explains why. The comparison of wood floors covers which floors need the largest gaps.