High Performance Partial Fill U Values
External masonry cavity walls - Partial fill, brick/block
Prescribed U Value W/m2K
(England and Wales) Extensions: 0.30
Renovation & Repair work: 0.35
New build requirement could range between 0.28 and 0.25
(Republic of Ireland) 0.27
(Scotland, with boiler SEDBUK ) 0.30
U Values (W/m2K)
Internal finishes: (a) plaster (b) plasterboard on dabs Block density
Block type
Block λ | 1400-1450kg/m3
Aircrete 7N
0.510
W/mK | | 750kg/m3
Aircrete
4N
0.190
W/mK | | 600kg/m3
Aircrete
2.8-3.5N
0.160
W/mK | | 470kg/m3
Medium
dense
0.110
W/mK | | Thikness
mm | a | b | a | b | a | b | a | b | | 70 | 0.36 | 0.34 | 0.33 | 0.31 | 0.32 | 0.31 | 0.30 | 0.29 | | 80 | 0.32 | 0.31 | 0.30 | 0.29 | 0.29 | 0.28 | 0.28 | 0.27 | | 90 | 0.30 | 0.29 | 0.28 | 0.27 | 0.27 | 0.26 | 0.26 | 0.25 |
Construction: 102mm Facing brick outer skin, cavity,
Rockwool High Performance Partial fill, internal concrete block 100mm.
| 
