External wall insulation is the application of an insulation layer to the outside of the facade, which is then finished with render (a rendered system, also known as ETICS) or with a ventilated rainscreen cladding. The insulation sits in front of the load-bearing structure, keeping the mass of the wall inside the thermal envelope.
Application
External wall insulation is widely used in renovation and in new-build projects where thermal bridges must be avoided. Because the insulation runs continuously across the entire facade — including lintels, columns and junctions — weak spots in the envelope are greatly reduced. The internal mass (such as concrete or brick) stays on the warm side and acts as a buffer, which makes the indoor climate more stable.
Characteristics
A rendered system consists of insulation boards (often mineral wool or EPS) bonded and anchored to the facade, with a reinforcement layer and a decorative render on top. In a rainscreen system, the facade cladding is mounted on battens at a distance, with a ventilated cavity between the insulation and the cladding. Both solutions improve the insulation value without losing internal floor space.
Related terms
- facade
- insulation
- facade cladding
- facade rendering
- cavity
- mineral wool
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