Simple layout
Few cuts and a rectangular room can justify a lower planning buffer.
Waste allowance is a planning choice for cuts, breakage, layout, and uncertainty—not a one-size-fits-all rule.
If the product or installer specifies an allowance, use that guidance. Otherwise, think about the room and layout: a square room with a straight lay normally has fewer difficult cuts than a diagonal, herringbone, or multi-doorway space.
Few cuts and a rectangular room can justify a lower planning buffer.
Doorways, closets, narrow returns, and mixed board lengths make more offcuts likely.
Diagonal and herringbone arrangements need a higher, explicit allowance.
On a 20 m² room with 2.2 m² packs, 10% means 22 m² or 10 packs; 15% means 23 m² or 11 packs. A five-percent change can therefore add a full pack. Compare scenarios against the actual product coverage instead of applying a percentage after purchase rounding.
Matching product may be hard to source later. If you choose to keep a spare pack, record it separately from layout waste so you can explain why it is included.