How to renovate an external wall

The external walls of a building make up a major part of the heat-transferring surfaces of the building envelope, which is why insulating them is essential for really efficient renovation.

Comparison of heat loss through the building envelope elements before and after proper ther-mal insulation is installed (source: Deutsche Energie-Agentur, adapted)

Comparison of heat loss through the building envelope elements before and after proper thermal insulation is installed (source: Deutsche Energie-Agentur, adapted)

External walls can basically be insulated in three ways: with external, cavity wall, or interior insulation.

Which of these options is chosen, depends, among other things, on the state of the building.