Building extra living areas within the attic is a great way to maximise the space within a house without increasing the footprint.
To keep a lid on heating bills, ensure compliance with building regulations and maximise occupant comfort, it is essential that habitable loft spaces are well insulated and airtight. Isover’s solution for this application features Metac insulation in combination with the Vario® airtightness and moisture management system.
Metac is a glass mineral wool ‘slab on a roll’ insulation for pitched roof rafter applications which delivers a range of benefits for the housebuilder, installer and home owner. As well as excellent thermal performance, Metac provides a proven acoustic benefit by helping reduce external noise from traffic, trains, planes and weather by up to 49dB. It also offers a more cost effective and easy to install solution than many alternative insulation materials.
Vario® XtraSafe is an innovative ‘smart’ vapour barrier which ideal for use within loft spaces. It delivers airtightness alongside active moisture management to help you meet and exceed the latest Building Regulations and protect the building fabric.
Building Regulations
| Country | Building Regulation | New Dwellings - Required U-value | Renovation - Required U-value |
|---|---|---|---|
| England | New Dwellings – Part L | 0.20 W/m2K | 0.18 W/m2k Conversion 0.18 W/m2k Extension |
| Wales | New Dwellings – Part L | 0.15 W/m2K | 0.18 W/m2K Conversion 0.15 W/m2K Extension |
| Scotland | New Dwellings – Section 6 | 0.15 W/m2K | 0.25 W/m2K Conversion 0.18/0.13 W/m2K Extension* |
* Lower U-value is required when existing wall and roof U-values are less than 0.70 and 0.25 respectively
Isover Solutions
The table below gives you some examples of how Metac can be used to achieve a defined U-value. For additional options, or for further guidance, please contact our Technical Advice Centre on 0115 945 1143| U-value achieved (W/m²k)* | Insulation between rafters @ 600m centres | Insulation below rafters |
|---|---|---|
| 0.19 | 125mm Metac | 53mm Gyproc ThermaLine PIR |
| 0.18 | 125mm Metac | 63mm Gyproc ThermaLine PIR |
| 0.17 | 175mm Metac | 50mm Metac between counterbattens plus 12.5mm Gyproc WallBoard |
| 0.16 | 175mm Metac | 53mm Gyproc ThermaLine PIR |
| 0.15 | 175mm Metac | 63mm Gyproc ThermaLine PIR |
| 0.14 | 200mm Metac | 53mm Gyproc ThermaLine PIR |
| 0.12 | 200mm Metac | 78mm Gyproc ThermaLine PIR |
* Based on 50mm wide rafters
