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FREE WASTE GUIDE FOR DRYLINING CONTRACTORS

Plasterboard waste percentage: What to allow on a job.

Allow 10% waste on plasterboard for simple runs, 15% where there are doors or windows, and 20% for complex layouts. Apply the percentage to the net area, after you've taken the openings off, then round up to whole boards.

Those are the figures from our free Drylining Waste Guide. This page shows how to pick the right one for a job and works through an example. The guide covers the rest of the materials list.

Plasterboard waste allowances

Simple rectangular room: 10%. Multiple openings, doors or windows: 15%. Complex angles, curves or reveals: 20%.

For fire-rated or acoustic board, always go up to the higher figure. Reordering specialist board is expensive and holds the job up.

Why 10% isn't enough on most jobs

Waste on real sites often runs well past 10%. UK government business guidance puts plasterboard wastage during installation at 10 to 35 per cent, and a UK site case study published by Eurogypsum reports the same range. Both name the same main causes: offcuts, damaged boards, poor storage and over-ordering.

So 10% is the figure for a clean, simple job. Every door or window adds cuts and offcuts you can't use anywhere else, which is why the allowance goes up to 15% once there are openings.

How to work out how many boards to order

  1. Measure every face you're boarding. A partition boarded both sides has two faces. A second layer of board counts as another face.

  2. Take off the doors and windows to get the net area.

  3. Add the waste allowance for the type of job.

  4. Divide by the area of one board and round up to whole boards. Never round down.

Worked example

A partition 10m long and 2.7m high, one layer of board each side, with two door openings, each 0.9m wide and 2.1m high. Boards are 2400 x 1200mm, so 2.88m² each.

  • One face: 10 x 2.7 = 27.00m²

  • Less the doors: 27.00 - (2 x 1.89) = 23.22m²

  • Both faces: 23.22 x 2 = 46.44m²

  • Add 15% because there are openings: 46.44 x 1.15 = 53.41m²

  • Boards: 53.41 ÷ 2.88 = 18.55, so order 19

On the net area alone you'd order 17 boards and come up two short.

Use this as a starting point. Check it against your board layout and the specification before you order.

What pushes waste up on site

Damaged stock is one of the main causes of waste. Keep boards stored flat and dry until they go up.

Wet, cold or awkward sites waste more board, so allow for that when you pick the figure. And order a buffer: running short halfway through a job usually costs more than sending surplus back.

What pushes waste up on site

Damaged stock is one of the main causes of waste in the NI Business Info guidance. Keep boards stored flat and dry until they go up.

Wet, cold or awkward sites waste more board, so allow for that when you pick the figure. And order a buffer: running short halfway through a job usually costs more than sending surplus back.

Disposal is a separate cost

The waste percentage covers what you order. Getting rid of the offcuts is a separate line on the quote. Plasterboard can't go to general landfill, so it has to be kept apart from other waste and sent for recycling or to a specialist site.

Common questions

Is 10% waste enough for plasterboard?

Only on simple runs with no openings. Use 15% once there are doors or windows, and 20% for complex layouts.

Do I add waste before or after taking off the openings?

After. Take the openings off first and apply the percentage to the net area. Adding it to the gross area overstates the order.

Does the percentage apply to both sides of a partition?

Yes. Work out the board area for every face and every layer, add them together, then apply the percentage to the total.

We're building QFitout, drylining quoting software that applies these allowances for you when you price a job.

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