Ventilated façade

A cladding detached from the wall by a continuous air cavity, open at the bottom and the top. The outer skin screens the rain, while the air rising in the cavity dries the insulation, sheds summer heat and keeps the wall dry. Insulation, water control and appearance become distinct layers, each optimised.

The ventilated façade applies the rainscreen principle to the envelope: it separates the aesthetic and first line of defence against water, entrusted to the outer cladding, from the insulation and weather seal, entrusted to the build-up on the wall. Between the two runs a ventilated air cavity that turns the façade into a dynamic system, able to manage water, vapour and heat.

Unlike an adhered cladding, the skin of a ventilated façade is not watertight: it accepts that a small amount of water passes through the open joints. It is the cavity that governs it. By equalising the pressure between outside and cavity, it cancels the force that would drive rain inward; the water that gets in runs down the back of the cladding and is drained at the bottom, never reaching the insulation. The façade sheds water by geometry and pressure, not by sealing.

The air in the cavity, warmed by radiation on the cladding, rises by the chimney effect, drawing fresh air from the base openings. This continuous flow does three jobs: it dries any moisture on the outer face of the insulation (which thus stays efficient), it carries off part of the summer heat before it reaches the wall (cutting cooling loads) and it vents the vapour migrating from inside. For it to work, the cavity must be continuous and the eaves and base openings correctly sized.

The cladding is held by a substructure of brackets and rails, usually aluminium or steel, anchored to the backing wall. These metal elements cross the insulation and break its continuity: they are the system's typical thermal bridge. They are controlled with thermal-break brackets, the minimum number needed for the structure, and careful fixing. The choice of materials, finally, is governed by reaction to fire: on a façade, where a fire can spread quickly upward, non-combustible insulation and cladding (class A) are often required by fire regulations.