Tips for Building
A partition is counted as two faces, not as wall area. Four metres of partition under a 2.40 m ceiling is 10 m² of wall but 20 m² of board. Stud centres follow: 600 mm in the ordinary case, 400 mm as soon as the partition takes wall tiles or exceeds the height the system allows.
For your ceiling height
Height m: no board to join
The board covers the height in one piece: you will only have vertical joints to fill, the easy ones, since their edges are tapered in the factory. Setting out on the floor and transferring it to the ceiling decides everything else.
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For your ceiling height
Height m: rows of board
The height exceeds the board: there will be a horizontal joint. Stagger it from one face to the other and from one row to the next, and use reinforced tape where the joint falls on a cut end, which has no tapered edge. Boards 2.7 m and 3 m long exist and often remove the joint.
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Depth stop: every screw at the right depth.
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For your ceiling height
Height m: check the permitted height
Above 3 m, centres usually drop to 400 mm, studs change section and a second layer becomes necessary: the system sheet gives the exact limit. A board lifter and a pole sander hire by the day and change the job.
The assumptions behind this calculation
- Boards: both faces are counted, multiplied by the number of layers, and your waste allowance is added. The calculation ignores the set-out: a partition with a door in it wastes a little more in offcuts.
- Framing: one track at the floor and one at the ceiling, so twice the length, in 3 m lengths. Studs are counted at the centres you set, plus one at the end. Doubled studs around a door and noggins for heavy fixings are added by hand.
- Screws: one screw every 300 mm on every stud the board crosses, rounded up to the box of 50. A stud at a board joint takes screws from both boards.
- Tape and compound: vertical joints between boards, horizontal joints where the height exceeds the board, internal angles at both ends and the junction with the ceiling. Compound is counted at 0.5 kg per m² of visible face, which matches the three coats of an ordinary joint.
- Mineral wool: the area of the partition, plus 5 percent. Thickness follows the stud width, not the target performance alone.
What this calculator does not replace
It gives quantities, not a system. The maximum height depends on the stud section, its centres and the number of layers: that figure lives in the system manufacturer's data sheet, and only that sheet counts. A fire-rated partition, a partition in a wet room, or one that has to reach a stated sound reduction is a complete system, boards and wool included, and is not assembled piece by piece.
A plasterboard partition carries nothing. Before opening up or removing an existing wall, have it checked that the wall is not structural.
The steps of the job, in order
Frequently asked questions
400 or 600 mm centres?
600 mm is the ordinary case for a dividing partition. You drop to 400 mm when the partition takes wall tiles, when it exceeds the height allowed at 600 mm, or when the system calls for it to reach a stated performance. At 400 mm, allow a third more studs and screws.
Are boards fixed vertically or horizontally?
Vertically on a partition is the ordinary way: the joints land on studs and the tapered edges are easy to fill. Horizontal fixing appears on wall linings and ceilings, with staggering rules that belong to the system.
How thick should the mineral wool be?
Thickness is capped by the stud width: 45 mm of wool in a 48 mm frame, 70 mm in a 70 mm one. Wool that is squashed or folded loses the point. It is the wool, not the board, that does most of the sound reduction in a partition.