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Habitable attic insulation – System 10 Premium
The highest-performing Isoflect package: Roof Pro over the roof boarding, Wolle between the rafters, two layers of Multistrat and Gold in phase 1, the sealed air layer and Multistrat in phase 2.
Technical content: Bogdan Ivănescu, graduate engineer, PhD candidate at the Technical University of Cluj-Napoca · updated on 16.10.2026
What the package includes
Premium comprises all the layers of Medium and adds Roof Pro, or Roof Optim, over the roof boarding. Roof Pro is installed from the outside, together with the roof covering; the rest of the package is installed from the room side. Premium uses Wolle P1500, with λ 0.038, while Premium+ uses Wolle P2100, with λ 0.035; the remaining layers are the same.
Roof Pro or Roof Optim
The membrane is installed over the roof boarding, beneath the counter-battens, from the outside.
Wolle, over the full height
Wolle is installed between the rafters over their full height, without gaps. At 15 and 25 cm, the 5 cm layer (λ 0.038) is installed first, towards the exterior, and the 10 cm slabs towards the room. The 5 cm layer adheres very well to the porosity of the substrate and requires no anchoring whatsoever.
Two Multistrat layers and Gold
Multistrat is installed in two layers, with the aluminium facing the Wolle, and fixed with 6 mm staples. At the edges it is taken down beneath the perimeter profile, so that the layer remains continuous and airtight. Gold is installed directly on the Multistrat and fixed with 2.5 cm screws.
Profiles and Multistrat
The CD 60/27 metal profile framework forms the sealed air layer of at least 3 cm. Multistrat is installed on the profiles, before the plasterboard.
System 10 Basic
The basic package for the habitable attic.
See the package →
Another packageSystem 10 Medium
The complete membrane package.
See the package →
Package values
For each thickness of Wolle between the rafters.
System 10 Premium (Wolle P1500, λ 0.038)
| Wolle | R m²·K/W | U W/m²·K | Equiv. λ W/(m·K) | Conventional insulation λ 0.038 |
|---|---|---|---|---|
| 10 cm 10 cm λ 0.038 | 5,986 | 0,167 | 0,02640 | 22.7 cm |
| 15 cm 10 cm λ 0.038 + 5 cm λ 0.038 | 7,301 | 0,137 | 0,02849 | 27.7 cm |
| 20 cm 2 × 10 cm λ 0.038 | 8,617 | 0,116 | 0,02994 | 32.7 cm |
| 25 cm 2 × 10 cm λ 0.038 + 5 cm λ 0.038 | 9,933 | 0,101 | 0,03101 | 37.7 cm |
The values apply to the entire build-up of the package, with all the layers below, not to a single product. Calculated values, from the Isoflect document “System 10 thermal insulation packages”. “Conventional insulation” is the thickness that a conventional insulation with λ 0.038 would need in order to reach the same thermal resistance R.
The variant with Wolle P2100 (λ 0.035): System 10 Premium+ →
Installation steps
Click on the central image to enlarge it.
Products for this application
Warranty
- ✓Reflectiva Roof Pro: 30-year warranty, service life of over 50 years
- ✓Roof Optim: 15-year warranty, service life of over 30 years
- ✓Wolle: 50-year warranty (interior)
- ✓Reflectiva Gold: 50-year warranty, service life of at least 50 years
- ✓Reflectiva Multistrat: 50-year warranty, service life of at least 50 years
Frequently asked questions
What is the difference between Premium and Premium+?
Premium uses Wolle λ 0.038, while Premium+ uses Wolle λ 0.035. The other layers are the same; each variant has its table of values on its own page.
Can I use Roof Optim instead of Roof Pro?
Yes, the package can be built with Roof Pro or with Roof Optim, over the roof boarding.
On which side is the aluminium of the Multistrat placed in phase 1?
Towards the Wolle, for both layers.
What does the equivalent thickness of a conventional insulation mean?
It is the thickness that a conventional insulation with λ 0.038 would need in order to reach the same thermal resistance R as the package: R × 0.038.
See and touch the products before ordering
The Isoflect sample pack contains samples of the reflective membranes and of Wolle wool insulation, so that you can compare the materials at home or on site.