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Habitable attic insulation – System 10 Medium
The complete membrane package: 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
Medium is installed from the room side. Wolle is installed between the rafters; in phase 1, two layers of Multistrat and Gold are installed; the metal profile framework forms a sealed air layer of at least 3 cm; in phase 2, Multistrat is installed, and the build-up is then closed with plasterboard. Medium uses Wolle P1500, with λ 0.038, while Medium+ uses Wolle P2100, with λ 0.035; the remaining layers are the same.
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.
Minimum 3 cm
The CD 60/27 metal profile framework forms the sealed air layer between the two phases.
Reflectiva Multistrat
Multistrat is installed on the profiles, with the aluminium facing the air layer, before the plasterboard.
System 10 Basic
The basic package for the habitable attic.
See the package →
Another packageSystem 10 Premium
The highest-performing Isoflect package.
See the package →
Package values
For each thickness of Wolle between the rafters.
System 10 Medium (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 | 5,686 | 0,176 | 0,02779 | 21.6 cm |
| 15 cm 10 cm λ 0.038 + 5 cm λ 0.038 | 7,001 | 0,143 | 0,02971 | 26.6 cm |
| 20 cm 2 × 10 cm λ 0.038 | 8,317 | 0,120 | 0,03102 | 31.6 cm |
| 25 cm 2 × 10 cm λ 0.038 + 5 cm λ 0.038 | 9,633 | 0,104 | 0,03197 | 36.6 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 Medium+ →
Installation steps
Click on the central image to enlarge it.
Products for this application
Warranty
- ✓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 Medium and Medium+?
Medium uses Wolle λ 0.038, while Medium+ uses Wolle λ 0.035. The other layers are the same; each variant has its table of values on its own page.
On which side is the aluminium of the Multistrat placed in phase 1?
Towards the Wolle, for both layers.
Can Medium be built with Roof Pro or Roof Optim?
Yes. Roof Pro or Roof Optim, beneath the roof covering, is optional. Medium with Roof Pro or Roof Optim becomes the Premium package.
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.