Partitions
Acoustic insulation roll or slab for partition cavities
- where
- insulation area (m²)
- partition length (m)
- partition height (m)
- openings (m²)
- cavities to fill
- layers per cavity
- packs
- waste allowance (%)
- coverage per pack (m²)
Explain this equation
Works out the area of partition cavity to insulate and how many packs of roll or slab to order.
L and H give the wall area; Ao is taken off for doors and windows. c is the number of separate cavities (two for a twin frame with quilt in each) and k the layers in each cavity. P is the packs needed: area plus waste w, divided by the pack coverage Cp.
Partition roll is made 600 mm wide to friction-fit between studs at 600 mm centres, so the whole wall area is covered without deducting studs. Rounding up gives whole packs.
Sense check: a 50 mm pack of about 15.6 m² does a 6 m × 2.7 m wall with a door. Double the thickness and the pack covers roughly half the area.
Watch out: pack coverage depends on product and thickness, so read it off the pack you are buying.
Number of packs of partition roll or slab to fill the stud cavities.
Enter your values to see the result.
Good to know
600 mm wide partition roll friction-fits between studs at 600 mm centres, so the full wall area is covered. Isover APR 1200 50 mm comes as 2 × 600 × 13000 mm, 15.6 m² per pack; thicker rolls and slabs cover less per pack, so always enter the coverage printed on the pack or data sheet. The insulation thickness and density must match the system specification (many fire-rated deflection heads need stone wool of at least 33 kg/m³).
Common mistake
Ordering by wall area for a twin-frame wall that needs quilt in both frames, or buying thicker roll without checking the reduced pack coverage.
Limits
Area-based. Does not deduct stud area (studs are within the roll width). Check the acoustic and fire specification for the required thickness and product.
Sources
- Isover Acoustic Partition Roll APR 1200, 50 mm: 2 × 600 × 13000 mm, 15.6 m² per pack (Jewson listing)
- British Gypsum, Best Practice Guide BPG002 Deflection heads (minimum 20 mm stud engagement in the head channel at all times; DC channel 50 mm flanges, EDC 70 mm; up to 50 mm total movement)
- British Gypsum, White Book Specification Selector (fire, acoustic and height performance of each partition and ceiling system)
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.