Loft Boarding Cost Calculator

How it is calculated

The tool works in square metres and metres. Board area is length × width. The number of boards is ceil(floor area × (1 + waste ÷ 100) ÷ board area), always rounded up to a whole board. Cost is boards × price per board, shown in dollars, and cost per m² is that total divided by your floor area (not the area including waste). Floor area must be above zero. The other four fields are optional: a blank one uses a default of 1.22 m × 0.32 m for the board, a price of 8 and a waste allowance of 10 %. A value you actually type is never replaced: a board length or width of zero or less, a negative price, or a waste below 0 or above 100 shows no result. A price or waste of 0 is accepted. Only boards are priced; fixings, insulation, labour and raised platforms are not included.

Common mistakes

• Typing board sizes in millimetres or centimetres. Lengths are metres, so 2.4 and 0.6, not 2400 and 600; entering 122 and 32 gives no result, because boards longer than 6 m or wider than 1.5 m are rejected.
• Using the full house footprint instead of the boardable area. Areas under the eaves, around the tank or beside the hatch you will not board should be left out.
• Leaving fields blank and assuming they count as zero. A blank board size, price or waste uses a default (1.22 × 0.32 m, 8, 10 %), which may not match what you are buying; type the real figures.
• Entering waste as a decimal, such as 0.1 for 10 %. The field is a percentage, so 0.1 means a tenth of one percent, and a value above 100 shows no result.
• Treating the cost as the full project price. Screws, battens, raised legs for insulation depth and labour are not counted.