Rainscreen Cladding Details
Rainscreen Cladding Introduction
Rainscreen cladding provides an outer layer to the building that screens the rain down its surface. The joints of the system are often left open, to allow any excess moisture to pass through, and be drained down the cavity. The backing wall or frame is usually fitted with insulation with a water resistant layer to provide the weather protection. Rainscreen cladding systems are popular and can be seen in a variety of shapes, sizes and materials including timber, ceramic tiles, terracotta, render, metal, laminates to name a few. It is worth seeking out some manufacturers literature to get a true sense of the options available.
Rainscreen cladding systems were developed when standard cladding joints were being penetrated by water due to the outside air pressure being greater than pressure inside the joint. The rainscreen system allows water to enter the joint but ensures the air pressure in the void is the same as the air pressure outside. The main functions of a rainscreen system are to provide a decorative weather resistant layer for the waterproofing system behind, to provide a protective layer to the thermal insulation fixed to the face of the structure and suitably drain any excess moisture down the cavity and away from the building. Later we will look at some rainscreen cladding details examples.
The void behind the cavity has the potential to spread smoke and flame, therefore cavity barriers must be installed in accordance with the Building Regulations.
Metal rainscreen cladding
A metal rainscreen system allows wind blown rain water to pass through the joints between panels and drain away down the cavity. The panels are installed on a metal frame system, fixed to the concrete or steel structural frame. Behind the cavity sits the waterproofed thermal insulation. The backing wall is not visible from the outside so is usually constructed of an economic material.
The metal panels can be visually striking with crisp lines. Most systems tend to avoid having visible fixings by using a hook on system or slot system. Different manufacturers have developed a variety of fixing and installation options that allow for a number of configurations.
When working with openings to the rainscreen, in order to avoid staining sills are usually formed to direct rainwater to the sides of the opening and down the joints between panels, rather than directly down the face of the panel below.
See below for some metal rainscreen cladding details examples.
Metal Rainscreen Cladding Details
Masonry rainscreen cladding
As with the stone facings we explored earlier, the masonry cladding can be designed as a rainscreen if desired. The panels are individually supported but the rainscreen fixing system, with the joints remaining open to allow rainwater to pass through the facing and drain down the cavity.
Terracotta rainscreen cladding is a more recent development and proving popular. The panels are fixed to a vertical or horizontal framing system. The panels are available in a variety of colours and textures. The panels remain relatively lightweight due to their hollow extruded profile.
As well as terracotta panels, it is also possible to use terracotta shingles which are fixed to horizontal rails. Finishing trims are usually made from folded aluminium or rolled steel channels.
See below for some masonry rainscreen cladding details examples.