EXTERNAL WALL INSULATION SYSTEMS / LAMELLA /

THERMAL PERFORMANCE

The thermal insulation requirements of the Building Regulations call for levels of thermal resistance for walls that can easily be achieved through the use of external wall insulation.

PermaRock Lamella Insulation has a thermal conductivity of 0.040 W/mK when tested in accordance with BS EN 12667 and BS EN 12939, and thermal calculations are carried out for each project to determine the optimum thickness of insulation required to achieve any required U-value.

PermaRock Lamella Insulation Boards are available in a range of thicknesses from 30 mm to 300 mm depending on the individual project requirements. The table above shows how the PermaRock Lamella System can achieve a range of target U-values for a number of wall constructions.


PERMAROCK LAMELLA INSULATION BOARD THICKNESS (mm) REQUIRED TO ACHIEVE THE TARGET U-VALUE SHOWN*

Solid 229 mm brick102 mm brick 50 mm cavity 100 mm block200 mm no-fines concrete 17 mm render150 mm lightweight metal frame 10 mm Pyrok89 mm timber stud frame 12 mm plywood140 mm aerated concrete block (7 N/mm2)
U-VALUE (W/m2L)solid 229 mm brick102 mm brick
50 mm cavity
100 mm block		200 mm no-fines150 mm lightweight metal frame 10 mm Pyrok89 mm timber stud frame 12 mm plywood140 mm aerated concrete block (7 N/mm2)
0.35959095959075
0.3210510010510510085
0.3011510511511511095
0.27130120125130120110
0.25140135140140135120
0.20180170175180170160
0.15250240250240240230

* Based on PermaRock Lamella System incorporating PermaRock Lamella Insulation Boards (0.040 W/mK) and with plaster or plasterboard internally and PermaRock K-finish Acrylic Textured Render decorative finish externally. The U-values shown are indicative only and take into account the effects of cold bridging in accordance with BS EN ISO 6946:1997. For complete U-value and condensation risk analyses for specific wall constructions please contact PermaRock's Technical Department.