Retrofit in air layers of cavity walls from the 80s
/Nitpicking mode on
Significant air layers in cavity walls only existed in buildings from around 1900 to the early 1960s.
The layer thickness ranged between 2 cm and a maximum of 15 cm. Mostly, however, a 6-8 cm air layer was left, only in older buildings, especially villas from the turn of the century (1900), air layers between 12 and 15 cm can be found.
From the 1960s onwards, the clinker was mostly installed without an air layer, but with a mortar joint in a "sharp mix" as a moisture barrier directly in front of the load-bearing masonry. Since everything was allowed here until 1.11.1977, there are also outliers and special constructions within this timeframe. My old building, for example, from 1959, has according to the building permit a 4 cm air layer between the load-bearing wall and outer masonry. However, during the inspection for the planned injection insulation, we then discovered that 2 cm polystyrene boards had already been glued over the entire surface to the outer wall.
From 1977/78 onwards, clinker facades with insulation and partly with ventilation were installed again—but nothing is injected anymore because something is already inside.