Rainscreen Cladding Systems

A rainscreen is a ventilated cladding system in which an open-jointed outer panel screen is held off the building’s weather-tight wall on a cavity, so that the two surfaces share the job of keeping rain out. The outer screen breaks the force of wind-driven rain and gives the building its appearance; the cavity behind drains and ventilates away the small amount of water that gets past; and the real air-and-water barrier is the back-up wall behind the cavity.

A different philosophy from sealed cladding

A sealed (face-sealed) cladding tries to stop all water at a single, perfectly sealed outer face — a line that inevitably degrades and leaks. The rainscreen accepts that some water will pass the outer joints and designs for it: the cavity drains and dries, and the protected back-up wall stays dry. This drained-and-ventilated, pressure-managed approach is far more robust and forgiving, which is why rainscreen is the dominant philosophy for opaque cladding on modern commercial and residential buildings.

The science behind the rainscreen is pressure equalisation. Wind-driven rain is pushed through a joint by the pressure difference across it; if that pressure difference can be removed, the main force driving water inward disappears.

Drained-and-ventilated vs pressure-equalised

Two related strategies are used. A drained and back-ventilated rainscreen relies on the cavity to drain and evaporate any water that passes the open joints, with continuous ventilation top and bottom. A pressure-equalised rainscreen (PER) goes further, compartmentalising the cavity so its air pressure rapidly equalises with the outside; with little or no pressure drop across the outer joint, very little water is driven in at all. True pressure equalisation needs the cavity to be reasonably air-tight to the inside (the back-up wall does that) and vented to the outside, with compartment baffles limiting air movement behind the panels.

The back-up wall does the sealing

Crucially, the outer screen is not the weatherproof line — the air-tight, water-tight barrier is on the back-up wall (a breather membrane or a sealed sheathing board over the structural wall). This division of labour is the essence of the system: appearance and rain-breaking outside, sealing and insulation inside.

Reading from outside in, a rainscreen is an assembly of four coordinated layers.

Outer panel screen

The visible cladding panels — metal, composite, terracotta, stone, fibre-cement, HPL, ceramic, GRC or timber — are open-jointed (open or baffled joints rather than sealed ones) and carry the architecture. Panel choice is covered in the dedicated cladding-material entries; the rainscreen is the way they are hung and drained.

Cavity and ventilation

A continuous air cavity (typically 25–50 mm) separates the panel from the insulation, allowing drainage and back-ventilation. Openings at the base, top and around openings admit and exhaust air; the cavity must be kept clear and its ventilation paths protected by cavity barriers where fire compartmentation requires.

Support system (sub-framework)

The panels are carried on a sub-framework of brackets and rails — usually aluminium, sometimes stainless steel or treated timber — fixed back to the structure. Brackets project through the insulation to set the cavity depth and are designed with thermal isolators to limit the cold bridge they create. Helping hands, T-rails, L-rails and proprietary carrier systems make up this layer.

Insulation and back-up wall

Continuous insulation is fixed to the structural back-up wall (concrete, blockwork or a steel/SFS framed wall with sheathing), outboard of the air-and-vapour control line. The back-up wall and its membrane form the true weather and air barrier, kept dry and protected by everything outboard of it.

How the panel is attached sets both the appearance and the cost of a rainscreen, and ranges from cheap and visible to expensive and seamless.

Face-fixed, secret-fix and cassette

Face-fixed panels are screwed or riveted through the face into the rails — the simplest and cheapest, with the fixings visible (often colour-matched). Secret-fix (hook-on) systems hang the panel on undercut anchors or hooks engaged with the rails, leaving a clean unbroken face. Cassette panels are folded into trays that hook or clip onto the carrier, giving a crisp, deep-reveal modern appearance. Clip and extruded-rail systems suit plank and linear panels. The choice trades cost, replaceability and the desired joint pattern against the seamless look.

Adjustability and tolerance

The bracket-and-rail system must take up the considerable tolerance of the structural wall while setting the panels to a flat, true plane with consistent joints. Slotted brackets and adjustable rails provide three-dimensional adjustment, and the setting-out is controlled from a continuous datum to keep joint lines true across the elevation.

The rainscreen’s continuous outboard insulation is excellent for thermal performance — it wraps the structure in an unbroken insulating layer — but the brackets that pass through it to carry the panels are a notorious cold bridge that must be controlled.

Continuous insulation, broken by brackets

Placing insulation outboard of the structure keeps the wall warm, reduces condensation risk and avoids the thermal bridging of insulation set between studs. The penalty is the support brackets, which are highly conductive metal piercing the insulation at regular spacing; left unaddressed they can erode a large fraction of the insulation’s benefit. Thermally broken brackets (with isolating pads or low-conductivity composite sections), minimised bracket numbers and point-fixed rather than continuous rails all reduce the bridging, and the residual effect is quantified as a point or linear thermal transmittance (chi or Psi) added to the wall U-value calculation per ISO 6946 and ISO 10211.

Cavity and condensation

The ventilated cavity also helps manage moisture: it lets the back-up wall and insulation dry outwards, and the breather membrane allows vapour to escape while resisting liquid water. Correct vapour-control and air-barrier detailing on the warm side keeps interstitial condensation under control.

Fire safety is the most consequential aspect of rainscreen design. The ventilated cavity that makes the system work is also a concealed, oxygen-fed vertical pathway that can allow fire to spread rapidly up a building — the mechanism implicated in several catastrophic façade fires. Regulation in this area has tightened dramatically.

The cavity as a fire route

A continuous open cavity behind combustible panels or insulation can act as a chimney, drawing flame up the building far faster than a solid wall would burn. The two defences are material non-combustibility and cavity compartmentation.

Non-combustible materials and cavity barriers

Many jurisdictions now require the panels, insulation and cavity components on tall and high-risk buildings to be non-combustible — Euroclass A1 or A2-s1,d0 to EN 13501-1 — effectively excluding combustible ACM cores, foamed plastic insulation and similar from those buildings (for example, England’s ban on combustible materials in the external walls of tall residential buildings). Cavity barriers — intumescent or mineral-wool closures — are installed horizontally and vertically and around openings to subdivide the cavity and close it in a fire, while still permitting the ventilation the system needs (often using intumescent open-state barriers that seal only when heated). The fire strategy and the reaction-to-fire and fire-spread classifications (EN 13501-1, BS 8414 / BR 135 large-scale test where required) are central to any rainscreen specification.

Although the rainscreen abandons the single sealed face, it is still engineered and tested for the full range of façade loads.

Weathertightness

Watertightness is a property of the whole system — the draining cavity and the back-up wall barrier — rather than of the open outer joints. Performance is assessed against the curtain-wall/cladding framework (the EN 12152/12154/12155 family and the CWCT Standard and Test Methods for the UK), with particular attention to the base, head, corners and the junctions around windows and openings, where most water management is concentrated.

Wind load and structure

The panels and their fixings resist wind pressure and (critically) suction, which tries to pull panels off the wall; the sub-framework transfers these loads to the structure. Panel spans, fixing pull-out capacities and rail spans are engineered to the design wind loads (EN 1991-1-4), with safety factors against panel detachment — a key serviceability and safety check given the consequences of a panel coming loose at height. Differential movement between the panels and the structure is absorbed by the adjustable, sliding support connections.

Beyond weather and fire, the rainscreen contributes to acoustic and long-term durability performance.

Acoustic

The mass of the back-up wall does most of the acoustic work; the outer panel and cavity add a modest further reduction and help break up sound reflections. For demanding acoustic environments the back-up wall construction (mass, isolation) is the principal lever, with the rainscreen layer a secondary contributor.

Durability and replaceability

One of the rainscreen’s practical virtues is maintainability: because panels are mechanically fixed and the weather barrier is protected behind them, individual damaged panels can usually be replaced without disturbing the waterproofing, and the protected back-up barrier enjoys a long, sheltered life. Panel durability depends on the material (covered in the cladding-material entries) and its finish; the support system is designed for the building’s full service life in the relevant corrosion environment.

Rainscreen performance lives in the details — the base, head, corners, movement joints and especially the junctions with windows and doors, where the drained cavity must be closed, flashed and drained without bridging the weather line.

Critical junctions

Window and door perimeters, the base of the cavity (where collected water is drained and weeped out), the head and parapet (where the cavity is closed and vented), external and internal corners, and movement joints are the make-or-break details. Each must maintain drainage, ventilation, the continuity of the back-up air/water barrier, and the fire cavity-barrier line simultaneously.

Testing and standards

Systems are tested and specified to the CWCT Standard for Systemised Building Envelopes and the EN cladding framework; fixings and anchors are tested for pull-out; and fire performance is demonstrated by reaction-to-fire classification and, where required for tall buildings, large-scale system fire testing (BS 8414 assessed to BR 135, or equivalent). Bracket thermal performance is calculated and the whole-wall U-value verified.

Rainscreen cladding is the default opaque-wall technology for a vast range of contemporary buildings, precisely because the same drained-and-ventilated principle works with almost any panel material.

It clads commercial offices, residential and mixed-use towers, schools, hospitals, retail and leisure buildings, and is the standard re-cladding solution for refurbishment and over-cladding of existing structures. The specific panel — aluminium and composite, metal, terracotta, stone, fibre-cement, ceramic, HPL, GRC — is chosen for appearance, durability, weight and (now critically) fire performance, but the rainscreen way of hanging and draining it is common to all. Each panel family has its own dedicated entry in this Systems library.

Rainscreen cladding draws on the cladding, fire, structural and building-physics standards together, and — since the systems combine many products — relies heavily on system testing and engineered detailing.

Applicable frameworks

Performance and testing follow the CWCT Standard and Test Methods and the EN 12152/12154/12155 family; wind loading follows EN 1991-1-4 and structural design the Eurocodes (EN 1999 for aluminium support, EN 1993 for steel); reaction-to-fire and fire-spread follow EN 13501-1 and, where required, BS 8414 / BR 135 large-scale tests, with national bans on combustible external-wall materials (e.g. the English Building Regulations) applying to tall buildings; thermal performance follows ISO 6946 and ISO 10211 (bracket bridging). Individual panel products carry their own product standards and CE/UKCA marking, and anchors and fixings are assessed to the relevant ETA routes.

The rainscreen’s sustainability strengths are durability, repairability and the continuous insulation it enables; its weaknesses are the extra material of the panel-plus-support layer and the embodied carbon of the panels themselves.

The continuous outboard insulation it carries is among the most effective ways to reduce a building’s operational energy, and the protected, long-lived back-up barrier reduces lifetime maintenance. Mechanically fixed panels can be removed, repaired and replaced individually, and — with aluminium support systems and metal, stone or terracotta panels — the components are recyclable and, increasingly, designed for disassembly with material passports. Against this, the system adds a second material layer and its support, so the embodied carbon depends strongly on the panel material chosen (lightweight recycled-content metal and long-life terracotta or stone score well; some composite and plastic-rich panels less so). Design for disassembly, recycled-content support systems and durable, recyclable panels are the levers for a low-impact rainscreen.

A rainscreen is an assembly of products from several specialists: the carrier/support-system makers, the fixing and anchor manufacturers, the insulation and cavity-barrier makers, and the panel manufacturers (whose products are covered in the dedicated cladding-material entries).

Support systems, fixings, insulation & panels

• SFS (NVELOPE) Heerbrugg, Switzerland — rainscreen support systems & fixings
• Nvelope Rainscreen Systems UK — aluminium carrier systems
• Sotech (Optima) Walsall, UK — rainscreen cladding systems
• Fischer Waldachtal, Germany — façade anchors & rainscreen fixings
• Rockwool / Rockpanel Roermond, Netherlands — non-combustible boards & insulation
• Trespa Weert, Netherlands — HPL rainscreen panels
• Equitone (Etex) Belgium — fibre-cement rainscreen panels

Panel materials & specialist contractors

The visible panels come from the metal, composite, terracotta, stone, ceramic, fibre-cement, HPL and GRC manufacturers covered elsewhere in this library, and the complete systems are designed, supplied and installed by specialist cladding contractors. Curtain-wall system houses (Schüco, Reynaers and others) also offer rainscreen and combined glazed-and-clad envelope systems.