Insulation packages for rafters 20 cm deep
Published on 06.06.2025 · Isoflect Insulation technical team
The complete Isoflect system for roofs with 20 cm rafters
6 insulation specifications – a single standard: performance without compromise
Whether your project is a passive house, an NZEB dwelling or a standard building with modern requirements, the Isoflect System 10 system offers a perfectly adapted solution: six technical configurations, each with a different balance between performance, budget and composition. All of them are designed specifically for roofs with 20 cm rafters, so that no structural adaptation is necessary.
Thermal performance for all 6 specifications
| Configuration | R (m²·K/W) | U (W/m²·K) | λeq (W/m·K) |
|---|---|---|---|
| System 10 Premium+ – with Wolle P2100 | 9,068 | 0,110 | 0,0285 |
| System 10 Premium – with Wolle P1500 | 8,617 | 0,116 | 0,0299 |
| System 10 Medium+ – with Wolle P2100 | 8,768 | 0,114 | 0,0294 |
| System 10 Medium – with Wolle P1500 | 8,317 | 0,120 | 0,0310 |
| System 10 Basic+ – with Wolle P2100 | 8,164 | 0,122 | 0,0301 |
| System 10 Basic – with Wolle P1500 | 7,713 | 0,130 | 0,0319 |
R (m²K/W), thermal resistance: the extent to which the layer or assembly opposes the passage of heat; the higher it is, the better it insulates. What it means →U (W/m²K): how much heat passes through one m² at a difference of 1 °C between the interior and the exterior; the lower it is, the better (U = 1/R). What it means →λ (W/mK), thermal conductivity: how readily the material conducts heat; the lower it is, the better the material insulates. What it means →
All systems are designed for a fixed thickness of 20 cm, that is, the depth of the rafters, and include the complete package of interior and exterior membranes (depending on the specification).
Components of Isoflect System 10
Isoflect Wolle technical mineral wool:
Reflective membranes:
Benefits common to all configurations:
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No mould, no settling, no VOCs
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Eliminates thermal bridges, even in critical areas
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Complete protection against moisture and UV radiation
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Hydrophobic system with controlled vapour diffusion
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Fully recyclable materials without chemical additives
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Safe installation for teams – does not prickle and causes no discomfort
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Warranty for the service life of the building
Which package should you choose?
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Passive houses / NZEB / premium → System 10 Premium+
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Balanced performance-to-price ratio → System 10 Medium
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Optimised budgets → System 10 Basic
All versions offer performance superior to traditional insulation materials such as stone wool, cellulose or open-cell foam – at a much smaller total thickness.
See all available packages here:
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Isoflect System 10 –
The architecture of performance for the smart homes of the future.
Part of the complete guide: Insulating the habitable attic — cases, layers and thicknesses.
Not sure which Isoflect product suits you? See the complete map — which Isoflect product is installed in each area of the house or open the package configurator to find out exactly what you need and in what quantity.