EXTERNAL WALL INSULATION SYSTEMS / PHENOLIC /
THERMAL PERFORMANCE
The thermal insulation requirements of the Building Regulations Parts L1 and L2 call for levels of thermal resistance for walls that can easily be achieved through the use of external wall insulation.
PermaRock Phenolic Insulation has a thermal resistivity that is considerably higher than other commonly used external wall insulants and therefore enables the specifier easy access to low U-values without the need for thick insulation layers.
PermaRock Phenolic insulation has a lambda value of 0.021-0.024 W/m2K and boards are available in a range of thicknesses up to 100 mm. Thermal calculations are carried out for each project to determine the optimum thickness of insulation required to achieve the required U-value.
The table shows how current and future U-value requirements for walls can be achieved using the PermaRock Phenolic System.
| PERMAROCK PHENOLIC INSULATION BOARD THICKNESS (mm) REQUIRED TO ACHIEVE THE TARGET U-VALUE SHOWN* |
|  |  |  |  |  |  |
| U-VALUE (W/m2L) | solid 229 mm brick | 102 mm brick
50 mm cavity
100 mm block | 200 mm no-fines | 150 mm lightweight metal frame 10 mm Pyrok | 89 mm timber stud frame 12 mm plywood | 140 mm aerated concrete block (7 N/mm2) |
|
| 0.35 | 55 | 50 | 50 | 55 | 50 | 40 |
| 0.32 | 60 | 55 | 55 | 60 | 55 | 45 |
| 0.30 | 65 | 60 | 60 | 60 | 60 | 50 |
| 0.27 | 70 | 65 | 70 | 70 | 65 | 60 |
| 0.25 | 80 | 70 | 75 | 75 | 70 | 65 |
| 0.20 | 100 | 90 | 95 | 100 | 90 | 85 |
* Based on the PermaRock Phenolic System with an Acrylic Textured Render decorative finish, taking into account the effects of thermal bridging in accordance with BS EN ISO 6946:1997. The U-values are indicative only. For complete U-value and condensation risk analyses for specific wall constructions please contact PermaRock's Technical Department.