Drywall Partition Wall: Boards, Studs, Insulation and Screws
Short answer: a 4.5 × 2.6 m partition (11.7 m²) with CW 75 studs, one layer of 1200 mm boards on both sides and a 10 % allowance needs 11 boards, 9 CW studs and 4 UW tracks of 3 m, 13.51 m² of wool (3 packs), 351 TN 25 screws (1 box), 5.85 kg of joint compound and 23.4 m of tape. With two layers of boards on each side you need 22 boards and twice as many screws. The drywall calculator works this out from the area of one side of the wall.
Published:
What a partition wall is made of
- UW tracks – fixed to the floor and ceiling, with sealing tape underneath.
- CW studs – set into the tracks; the system manufacturer gives 625 mm centres, and closer spacing (417 or 312.5 mm) for heavier linings.
- Mineral wool in the cavity – for sound insulation; for a 75 mm cavity the manufacturer gives at least 60 mm of wool.
- Plasterboards on both sides, in one or two layers, fixed with TN drywall screws.
- Joint tape and compound, then skim coat and paint.
How to use the calculator – step by step
- 1. Choose the “partition wall” mode.
- 2. Enter the area of ONE side of the wall: length × height (4.5 × 2.6 = 11.7 m²). The calculator counts the boards for both sides itself.
- 3. Choose the board width (1200 mm; a 1200 × 2000 mm board covers 2.4 m²) and the number of layers.
- 4. Choose the CW/UW profile size (75 mm) and the tape type (mesh or paper).
- 5. Enter the waste allowance (10 %) and the compound bucket size (20 kg).
- 6. The result shows quantities and the number of packs; save them to a project or export a PDF.
Example: a 4.5 × 2.6 m wall between a room and a hallway
CW studs are counted as 2 m per m² of wall plus the allowance, which for a 2.6 m high wall matches studs at roughly 62.5 cm centres. If the wall is taller than 3 m, 3 m studs are too short – order them in the length you need.
| Material | Calculation | To buy |
|---|---|---|
| Boards 1200 mm, 1 layer | 11.7 ÷ 2.4 × 2 sides × 1.1 = 10.7 | 11 boards |
| CW 75 studs | 25.74 m | 9 pcs of 3 m |
| UW 75 tracks | 9.01 m | 4 pcs of 3 m |
| Mineral wool | 13.51 m² | 3 packs of 6 m² |
| TN 25 screws | 351 pcs | 1 box of 500 |
| Joint compound | 5.85 kg | 1 bucket of 20 kg |
| Joint tape | 23.4 m | 1 roll |
| Sealing tape | 9.36 m | 1 roll |
One or two layers of boards
A single layer of 12.5 mm boards is the cheapest and quickest to build. Two layers on each side give a stiffer wall, better sound insulation and more impact resistance, so they are chosen between flats, in bedrooms or where heavier items will hang on the wall. The same wall then needs 22 boards, 351 TN 25 screws for the first layer and 351 TN 35 screws for the second.
A door in the partition
The calculator does not deduct openings and does not count reinforced door profiles. Boards cut out for the door are usually reused for the head and narrow strips, so enter the wall area without deducting the door and add the reinforced profiles beside the opening separately, according to the manufacturer's system.
Most common mistakes
- Entering the area of both sides of the wall – the calculator would then count the boards twice.
- Leaving out the wool – a wall without it lets through considerably more sound.
- Stud spacing wider than the manufacturer allows for the wall height and lining.
- The same screws for both layers – the second layer needs longer screws (TN 35).
- Taking the consumption norms as exact: the calculator uses approximate norms per m², and the system manufacturer's data decide.
Sources and assumptions
CW stud centres (625, 417 or 312.5 mm) and the minimum wool thickness in the cavity are taken from the detail sheet for metal stud partitions. Consumption of profiles, screws, tape and compound per m² are approximate norms of the calculator, not manufacturer data; change the packs (3 m profile, box of 500 screws, 6 m² wool pack, 20 kg bucket) to match your supplier. These are typical values – the data on the pack or technical data sheet of the product you buy applies.
Frequently asked questions
How many boards, studs and screws for a 4.5 × 2.6 m wall?
With one layer of 1200 mm boards on both sides and a 10 % allowance: 11 boards, 9 CW studs and 4 UW tracks of 3 m, 351 TN 25 screws and 5.85 kg of joint compound.
At what spacing are CW studs installed?
The system manufacturer gives 625 mm centres, and closer spacing (417 or 312.5 mm) for heavier linings, tiles or taller walls.
How much wool goes into a wall with 75 mm studs?
The manufacturer gives at least 60 mm of wool for a 75 mm cavity. The calculator counts wool by wall area with an allowance: for 11.7 m² that is 13.51 m².
When is a double layer of boards worth it?
When sound insulation or wall strength matters, e.g. between flats or bedrooms. A wall of 11.7 m² then needs 22 boards.
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