Supplementary thermal insulation for walls using Finnfoam renovation panels

Finnfoam's renovation panel S40 is intended specifically for interior supplementary thermal insulation. In general, supplementary thermal insulation can be implemented using Finnfoam's standard rebated insulation panels, but the renovation panel S40 is more suitable for applications where you want to minimize the increase in the size of the structures. The thickness of the renovation panel is 40 mm, and it measures 600 x 2,600 mm. The panel is attached to the wall with batten strips (20 mm x 50 mm) that fit into the recesses at the edges of the panel. Thus, the insulation is pressed in between the existing wall and the strip at the seams. The airtightness of the seam can be increased further by applying a flexible foam sealant or sealing paste on the seam. This will ensure that the insulation is continuous and eliminates thermal bridging. The interior cladding or paneling is attached to the batten strips. The structure saves space and is airtight. It also does not interfere with the behavior of the timber structures and improves the moisture performance of the wall. A flexible foam sealant is used to seal the top and bottom edges and any lead-throughs. This ensures that the new wall is continuous and air-tight, without cold corners or draft.

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By renovating an existing wall (U value 0.28) built to the previous standards (valid from 1985 to 2003) with the Finnfoam S40 renovation panels, the insulation capacity of the wall would improve more than 30%. The new U value of the wall after renovation would be approximately 0.20 W/(m² K). In reality, the improvement might be even more significant, as the airtightness of the structure would also be improved. On average, the leakage rate of a timber framed house is 4. As the leakage rate is reduced to 1 by improving the airtightness, the energy consumption of a single-family house will be reduced by up to 15% as the result of the improved airtightness alone. The calculation of the U value does not consider the airtightness of the structure (leakage rate).

The relative improvement of the insulation capacity of even older walls would be more significant. If an existing wall was insulated with 100–120 mm of porous insulation material, the insulation capacity of the wall could be improved by more than 50% using Finnfoam S40 renovation panels. The U value of the wall would be 0.25.

The Finnfoam renovation panels have a high insulation capacity and have sufficient rigidity, even though the S40 panels are just 40 mm thick. The panels are comfortable to handle and easy to work on. The panels do not crumble or produce dust.

FI-300/40S renovation panel for supplementary thermal insulation

Thickness 40 mm

Width 600 mm

Length 2,600 mm

Supplementary thermal insulation of a wall with renovation panels.

Interior supplementary thermal insulation for a heated building using Finnfoam renovation panels

The Finnfoam renovation panels can be used to construct supplementary thermal insulation solutions quickly and cost-effectively. Finnfoam and foam sealant combine to produce a continuous and leak-proof insulation, which also functions as a vapor barrier. If the existing wall includes a plastic vapor barrier, the plastic has to be punctured with approximately 10 holes per square meter. This is done to eliminate areas within the structure that are placed between two vapor-proof layers.

Start insulating from a corner. In the corner, you can use screws and washers to fix the panel in place. Next, seal the end of the panel at the corner using flexible foam sealant. Leave a gap of approximately 10 mm at the top and bottom of the panel, to ensure that the foam sealant can be applied easily to the top and bottom seams as well.

The panels can be attached using batten strips (20 x 50). Before attaching the batten strip, apply some flexible foam sealant into the seam between the panels. The Finnfoam and the flexible foam sealant will be pressed in between the batten strip and the existing wall, thus ensuring a tight seam.

Interior cladding or paneling can be easily attached to the batten strips. Before you put up the interior cladding, remember to seal the top and bottom edges of the panels and any lead-throughs, such as wall sockets. The proper airtightness of a structure is part of its energy economy! The formula used to calculate the U value of a structure does not consider airtightness.