Retrofit insulation of the exterior walls
Source: Fotolia
Exterior wall insulation is a frequently recommended measure for improving the energy quality of buildings. It has a technical lifetime of 30 to 50 years.
For practical reasons as well as for structural physical reasons, in case of a modernisation of the exterior wall one should consider the simultaneous modernisation of windows and potentially the roof. Scaffolding work and connection details in this case would have to be done just once.
The achieved energy cost savings of a thermal insulation of an exterior wall also depend on the initial state.
U-values of selected constructions
Among other things, the energy performance of an exterior wall depends on the existing construction. Depending on the age of the building and on the region, a variety of constructions can be found. The age of the building alone only allows a limited inference of the energy quality.
The following table shows exemplary U-values of frequent exterior wall constructions.
| Exterior wall | |||
|---|---|---|---|
| Construction system | Year of construction | Structure of building element | U-Value W/(m²·K) |
| Brickwork, monolithic | before 1918 | 36,5 cm solid brick, plastered | 1.65 |
| Half-timber | before 1918 | 16 cm timber stud, partition, loam rendering | 1.66 |
| Mauerwerk, monolithisch | 1947-78 | 38 cm pumice stone hollow block, plastered | 1.14 |
| Mauerwerk, 2-schalig | 1969-78 | 24 cm vertically coring brick, 6 cm air cavity, 11,5 cm revetted brick layer, interior plaster | 1.01 |
| Mauerwerk, verkleidet | 1969-78 | 24 cm perforated sand-lime brick, 3 cm insulation, plastered / curtain wall | 0.78 |
| refurbished | 36,5 cm vertically coring brick, 12 cm insulation, plastered | 0.24 | |
| Mauerwerk, gedämmt | refurbished | 36,5 solid brick, 16 cm insulation, plastered | 0.22 |