Box coverage varies by product — anywhere from 18 to 30 square feet — so the count on the box is the number that matters, not the brand. Check it before ordering; it is printed on every carton.
Waste is about doorways and direction
Ten percent covers a normal rectangular room laid straight. Rooms with several doorways, closets and jogs waste more, because every transition starts a new cut.
Laying planks diagonally pushes waste to 15 percent or higher. Long planks in a narrow room also waste more than short planks, because the offcut from each row is often too short to start the next.
Leave the expansion gap
Floating floors move. Every manufacturer requires an expansion gap — usually a quarter to a half inch — around the entire perimeter, hidden by baseboard or quarter round.
Butting a floating floor tight to the wall is the most common installation failure. It has nowhere to go when it expands, so it buckles in the middle of the room.
Mix from several boxes
Plank colour and grain vary within a production run. Pulling from three or four open boxes as you work spreads the variation instead of leaving a dark patch across two rows.
Check the subfloor first
Most click-lock floors specify flatness within 3/16 of an inch over ten feet. Out-of-flat subfloor causes clicking joints to separate under foot traffic.
Fix the subfloor before the flooring arrives. It cannot be corrected with underlayment.
Acclimation, and whether it matters
Most manufacturers ask for the boxes to sit in the room where they will be installed for two or three days before installation, laid flat and unopened or opened depending on the product.
The reason is dimensional. Wood and laminate take on and give off moisture with the surrounding air, and a board installed dry in a humid house grows afterwards. If it has nowhere to grow, the floor buckles.
Rigid core vinyl is the exception — most of it needs only a day and some none at all. Check the specific instruction, because ignoring an acclimation requirement is one of the few things that reliably voids a floor warranty.
Which direction to run the boards
The convention is to run the boards along the longest wall of the room, or toward the main source of natural light. Both make a room read as larger and hide the seams better.
There is a structural consideration too. Over a wood subfloor, boards laid perpendicular to the joists are better supported than boards that run parallel with them.
Direction also changes waste. Running boards along a long room means fewer cuts and less offcut; running across it means a cut at both ends of every row. If the room is long and narrow, the difference in material is real.