Inside the house
Painting, flooring, tiling, boarding out. Doors and windows taken off for you.
The mistake running through this whole category is confusing wall area with floor area. A twelve by ten room has 120 square feet of floor and 352 square feet of wall, so working from the floor figure gives you about a third of the paint you need.
Wall area is the room's perimeter times its ceiling height. Doors and windows come off that, a waste allowance goes on, then you divide by whatever one unit of material covers — a tin, a box, a sheet or a bag.
- Baseboard & trim How many lengths of skirting, coving or picture rail a room takes.
- Drywall Sheets, screws, compound and tape for a room, with the openings taken off.
- Flooring Square footage for a room, plus how many boxes it takes with waste allowed for.
- Insulation Batts or rolls for a wall or ceiling, with the framing taken out.
- Paint Work out how much paint a room needs, with the doors and windows taken off.
- Tile How many tiles a floor or wall takes, with the grout gap and waste counted in.
- Wallpaper Rolls needed, counted in drops, with the pattern repeat allowed for.