Area, waste, then packs or lineal metres
Floating floors, which is laminate, hybrid and most engineered timber, are sold by the pack, and every pack states the area it covers. Solid tongue and groove boards are sold by the lineal metre. Either way the start is the same: floor area plus waste. Then divide by the pack coverage for packs, or by the board's cover width for lineal metres.
packs = area × (1 + waste) ÷ pack coverage, rounded up
lineal metres = area × (1 + waste) ÷ cover width (m), rounded up
| Room | Area | +10% | Packs at 2.2 m² | 85 mm boards |
|---|---|---|---|---|
| Bedroom 3 × 3 | 9.0 m² | 9.9 m² | 5 | 124 lm |
| Bedroom 4 × 3.5 | 14.0 m² | 15.4 m² | 7 | 193 lm |
| Living 6 × 5 | 30.0 m² | 33.0 m² | 15 | 413 lm |
| Whole house, 110 m² | 110 m² | 121 m² | 55 | 1,513 lm |
Waste
Every row of boards finishes at a wall with a cut, and the offcut only gets used if it is long enough to start the next row. In a plain rectangular room laid straight that adds up to about 10 percent. Diagonal layouts and herringbone patterns waste 15 percent or more, as do rooms with a fireplace, a bay window and three doorways. Keep the spare boards from the last pack; the colour batch will not be around when a board needs replacing.
Underlay and scotia
Floating floors go over an underlay unless it is already stuck to the boards. It softens the floor, takes some of the sound out, and on concrete it carries a plastic moisture barrier. Rolls commonly cover 10 to 20 square metres; enter the figure from the roll. The expansion gap around the edge is covered by scotia, a small quad moulding against the existing skirting, or by removing and refitting the skirting over the new floor, which looks better and costs a morning. The calculator gives the room perimeter for either.
Solid boards
Solid tongue and groove boards are laid over joists or a subfloor, secret nailed or glued and nailed, then sanded and coated. The face width once the tongue is in the groove is a few millimetres under the nominal size: 85 mm boards cover about 80 mm, 130 mm boards about 125. Boards come in random lengths and are sold by the lineal metre, so the calculator converts the area at the cover width you enter.
Worked example
A 4 × 3.5 m bedroom in hybrid planks at 2.2 m² a pack, laid straight. Area 14 m², with 10 percent waste 15.4 m², so 7 packs. Underlay at 10 m² a roll: two rolls. Scotia around 15 m of perimeter, 16 lm with cuts, less the doorway. In 85 mm solid boards the same room is 15.4 ÷ 0.08 = 193 lineal metres.
Common questions
How many packs do I need?
Area plus 10 percent, divided by the coverage on the pack, rounded up.
How much waste?
10 percent straight, 15 percent diagonal or herringbone.
Lineal metres of floorboards?
Area ÷ cover width in metres. 85 mm boards cover about 80 mm.
Is underlay needed?
Yes for a floating floor, unless attached, with a moisture barrier on concrete.
Quantities only. Acclimatisation, expansion gaps, subfloor moisture limits and fixing methods follow the flooring manufacturer's instructions.