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The two-layer reflective package
Additional thermal insulation for habitable attics: Gold and Multistrat, with the sealed air between them, add R = 2.09 m²K/W to the insulation between the rafters.
Technical content: Bogdan Ivănescu, graduate engineer, PhD candidate at the Technical University of Cluj-Napoca · updated on 16.10.2026
Three zones, each with its own role
The package comprises two membranes: Gold, beneath the rafters, once the insulation between them has been installed, and Multistrat, before the plasterboard or timber panelling. With the sealed air layer between them, it adds a tested thermal resistance of 2.09 m²K/W to what you already have. You no longer need a separate vapour barrier membrane towards the interior.
R (m²K/W), thermal resistance: the extent to which the layer or assembly resists the passage of heat; the higher it is, the better it insulates. What it means →R = 2.09 m²K/W is measured on the Gold + 6 cm air + Multistrat assembly. What it means →176 kWh per square metre, every year
The annual saving is calculated relative to an uninsulated roof, under Romanian climatic conditions. The thermal resistance of the membrane assembly, R = 2.09 m²K/W, is a tested value.
kWh/m²/year: the energy saved in one year per m², calculated relative to an uninsulated roof. What it means →Beneath the rafters
It is installed once the insulation between the rafters is in place. Supplied in 12 m² rolls.
Before cladding
It is installed before the plasterboard or timber panelling. Supplied in 30 m² rolls.
R 3.01 instead of 2.09
The same installation position, but with two layers of Multistrat in the first phase. You gain almost one additional m²K/W.
R = 3.01 m²K/W is derived from INCD URBAN-INCERC test report no. 7039 / 18.10.2023. What it means →Installation steps
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Frequently asked questions
How much does the package add to the existing insulation?
R = 2.09 m²K/W, a tested value for the membrane assembly with the sealed air layer.
Do I still need a vapour barrier?
Not a separate membrane towards the interior; the package assumes this role.
What do I gain with the four-layer variant?
R 3.01 instead of 2.09, with two layers of Multistrat in the first phase, in the same installation position.