Home · Applications · Timber floor in the attic, with walkable boardingTimber floor in the attic, without walkable boarding · without walkable boarding
Insulating the timber floor in the attic, without walkable boarding
Thermal insulation for the timber floor in the attic: Multistrat on the floor boarding and Wolle P800 from the roll on top.
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
Reflectiva Multistrat is laid over the boarding, with the aluminium facing up. Above it comes the Wolle thermal insulation fibre. Wolle P800 is rolled out directly over Multistrat, continuously and butt-jointed.
Multistrat occupies 5 mm
The Reflectiva Multistrat layer is only 5 mm thick. The emissivity is 0.05, and the reflectivity is 95–97%.
Emissivity: an emissivity of 0.05 means that the aluminium face radiates only 5% of the heat that an ordinary surface would radiate, and therefore does not give off heat by radiation. The lower it is, the better. What this means →Reflectivity: the proportion of the radiant heat reaching the membrane that is sent back. What this means →Continuous insulation, from the roll
Wolle is unrolled continuously, butt-jointed, so the insulation has no joints along its length. The attic, including the insulation, can be walked on: Wolle withstands foot traffic, does not tear and does not crumble.
50 or 100 mm
The starting point is 50 mm of Wolle. For 100 mm, lay two layers of roll.
Distance from the chimney
Around the chimney and any strong heat source above 120 °C, leave a clear zone of 50 cm all around.
With walkable boarding
If the attic is to be walked on, the Wolle boards are fitted between spacers, with walkable boarding laid over them.
See the application →
Installation steps
Click on the central image to enlarge it.
Products for this application
Warranty
- ✓Reflectiva Multistrat: 50-year warranty, service life of at least 50 years
Frequently asked questions
Which side of Multistrat should the aluminium face?
The aluminium faces up, and the grey side faces down, towards the boarding.
Can I walk on the insulation if I do not install walkable boarding?
Yes. Wolle withstands foot traffic, does not tear and does not crumble.
What should I do around the chimney?
Around the chimney and any strong heat source above 120 °C, leave a clear zone of 50 cm all around.
Configure the application
Choose the option and the insulation thickness, enter the attic surface area and view the quantity required for each product.
Your selection
Option Wolle insulation thicknessMaterial requirements
The quantities include 3% for wastage and are rounded up to whole rolls and packs.
Enter the surface area in order to request the quote.