Partitions
Partition height against the manufacturer's maximum height
- where
- height margin (mm)
- maximum height from the system table (mm)
- actual partition height (mm)
- height used (%)
- deflection limit at this height (mm)
Explain this equation
Compares the height of your partition with the maximum height the manufacturer publishes for that exact stud, centres and board build-up.
Hmax is the table figure and H the actual height, both in millimetres. M is the margin left (negative means too tall). U is the percentage of the allowed height used. d is H/240, the mid-height deflection the partition is allowed to reach under the 200 Pa test pressure that British Gypsum uses to set its heights.
The table height already combines stud stiffness, board stiffness, fire test limits and deflection, so the only sensible check on site is a straight comparison. The 240 comes from the L/240 deflection criterion: a 2.4 m wall may deflect 10 mm at mid-height.
Sense check: a 2.6 m wall against a 2.8 m limit uses about 93% of the height. A 4.2 m wall against a 4.0 m limit fails by 200 mm.
Watch out: heights differ for each stud gauge, centres and number of layers; read the right row.
Checks a partition height against the maximum height published for the exact system (stud size and gauge, centres and board layers).
Enter your values to see the result.
Good to know
Manufacturers publish one maximum height per system, for example British Gypsum A206002 (48 mm C studs at 600 mm, one layer of 15 mm WallBoard each side) is 2800 mm. British Gypsum bases its limiting heights on the lower of the fire-test height and a mid-height deflection of L/240 under a 200 Pa pressure, so the third output shows the deflection the system is allowed at your height. Taller partitions need deeper studs, 400 mm centres, boxed or back-to-back studs, extra board layers or a different system; take the new limit from the table, do not scale it yourself.
Common mistake
Using the height for a deeper stud or two-layer system when the job has a single layer, or reading a duty rating table as a height table.
Limits
This is a comparison only. The published height already includes the board stiffness, fire test height and duty; it cannot be calculated from stud properties alone. Heights over 4.2 m usually need deep flange channels.
Sources
- British Gypsum, GypWall Single Frame A206002 technical specification (48 mm C studs at 600 mm centres, 1 × 15 mm WallBoard each side, 80 mm thick, maximum height 2800 mm based on fire limit or deflection L/240 at 200 Pa, 25 mm screws)
- British Gypsum, White Book Specification Selector (fire, acoustic and height performance of each partition and ceiling system)
- Knauf Performer PC-50-055-6-1-15-WB-0 (NBS Source): Knauf 50 C studs at 600 mm centres, U channel floor, deep flange U channel head
Results are calculations from the published methods and manufacturer figures shown, and depend on the data you enter. Always follow the manufacturers’ system and product data, BS 8212, BS EN 13914 and Building Regulations. Coverage rates vary by product, background and thickness. Check prices, VAT and CIS rules with your own records and HMRC.