Rainscreen Cladding

Metal, terracotta, UHPC, GFRC, stone, fiber cement: today's façades can be clad in almost anything. What makes most of them work is the same principle behind the cladding, the rainscreen. Beau Designs helps architects, developers and contractors select the right cladding and, more importantly, design the wall behind it so it stays dry, efficient and code compliant.

What is a rainscreen?

A rainscreen is a wall with two lines of defense. The outer cladding sheds most of the rain. Behind it, a ventilated cavity lets any water that gets past drain away and lets the wall dry out. Behind the cavity, the air and water barrier on the backup wall is the true line of protection.

The cladding is the face of the building. The barrier is what keeps the building dry.

How it's built

  • Backup wall: steel studs with sheathing, concrete block or concrete

  • Air and water barrier: continuous across the whole wall and tied into every window, door and transition

  • Continuous insulation: typically mineral wool, outboard of the backup wall

  • Subframe: clips, rails and girts that hold the cladding, ideally thermally broken

  • Cavity: open at the base and top to drain and ventilate

  • Cladding: the visible finish, with open or closed joints

Why rainscreen?

  • Durability: water that gets behind the cladding drains and dries rather than being trapped.

  • Thermal performance: insulation outside the structure reduces thermal bridging and helps meet energy code.

  • Design freedom: almost any material, color, shape or texture can hang on the same basic system.

  • Quality and speed: most cladding is factory-finished, and systems can be panelized off site, much like unitized curtain wall.

  • Maintenance: individual panels can often be removed and replaced.

Cladding types

Metal panel. Aluminum plate, aluminum composite (ACM), zinc, copper, stainless steel and perforated or folded metal. Lightweight, crisp and available in endless finishes. ACM requires a fire-rated core and a tested wall assembly. Watch for oil-canning on large flat panels, and for dissimilar metal corrosion at fasteners.

Terracotta. Extruded fired clay panels and baguettes, with a long history on New York buildings. Extremely durable, colorfast and available in custom glazes and profiles. Requires careful attention to clip design, tolerances and breakage during handling and installation.

UHPC (ultra-high performance concrete). A fiber-reinforced concrete with very high strength, allowing thin, lightweight panels and complex three-dimensional shapes that conventional precast can't achieve. A premium material suited to sculptural and high-profile façades.

GFRC (glass fiber reinforced concrete). A thin, lightweight concrete skin, often on a steel stud frame, used for complex shapes, cornices and the replication of historic stone and terracotta. Quality control in fabrication and curing is critical to avoid cracking.

Natural stone. Thin stone panels on rails or kerf clips, offering the look of masonry with a lighter, drained system.

Fiber cement and porcelain. Economical, durable and widely used on low- and mid-rise buildings.

Brick. A traditional brick veneer is itself a drainage cavity wall, and thin brick or brick tile rainscreen systems offer a lighter alternative.

Fire

Rainscreen walls combine insulation, barriers, cavities and cladding, any of which can be combustible. Wall assemblies on taller buildings generally need to comply with NFPA 285 testing, and cavities need fire stopping at floor lines. Product substitutions during construction can quietly break a tested assembly, so they need careful review.

Where rainscreens go wrong

  • Treating the barrier as secondary. If the barrier fails, the cladding won't save the wall.

  • Gaps at transitions to windows, doors, curtain wall, roofs and the base of the wall.

  • Thermal bridging through steel girts and clips that undermines the insulation and energy code compliance.

  • Blocked cavities with no drainage or ventilation at the base and top.

  • Openings where the window, flashings and cladding returns all compete in a tight space.

  • Barrier left exposed to sunlight longer than the manufacturer allows before cladding is installed.

  • Tolerances and movement not accommodated in the subframe and joints.

  • Corrosion where dissimilar metals meet.

Quick guide

  • Cost-effective low or mid-rise: fiber cement, porcelain or metal panel

  • Crisp, modern high-rise: aluminum plate or composite metal panel

  • Warm, durable and contextual: terracotta or brick

  • Sculptural or thin, complex forms: UHPC

  • Ornament or historic replication: GFRC

  • Masonry look with less weight: thin stone or thin brick systems

How Beau Designs helps

  • Cladding and system selection balancing cost, performance and design

  • Barrier, insulation and subframe design and detailing

  • Transitions to windows, curtain wall, roofs and below grade

  • Thermal bridging and energy code compliance

  • Fire assembly and NFPA 285 review, including substitutions

  • Shop drawing and submittal review

  • Mockups, testing and construction observation

  • Investigation of existing cladding failures