Slate is an iconic roofing material that’s been a natural choice since the Roman empire and now its overall popularity and use as a rainscreen material is on the rise.

Globally, the overall market for slate is more than $1 billion, and it’s expected to reach nearly $1.4 billion by 2028. The rainscreen market is growing even faster and is expected to reach $20.43 billion by 2029, up from $11.30 billion in 2022, according to market research firm Exactitude Consultancy. Experts from the firm say the rainscreen cladding market is rising due to population growth, upscale residential interest, and increases in severe weather events.

A metamorphic rock formed from volcanic ash, slate can differ in color and character depending on where it is extracted. Most of the slate used today comes from Spain, and no matter the origin, slate has very low permeability to water, is non-combustible, and is unaffected by temperature changes and ultraviolet light. It’s a natural choice for exterior cladding beyond roofs, and it has proven itself as sustainable, adaptable, and dependable for about 2,000 years.

Sustainable Material

With thousands of companies making net zero commitments and 60% of large architecture firms implementing sustainability plans, the goal to optimize sustainable solutions has become a key driver of architecture in recent years.

While there are many newer building materials and systems on the market that offer low embodied carbon and environmental product declarations to back up those claims, there are few building materials with slate’s long track record for low environmental impact.

Slate has a low carbon footprint and an embodied carbon value that’s 16% or less than other roofing materials. “During its production process, it is only submitted to extraction and shaping,” says Jose Manuel Rivas from Cupa Pizarras, the producer of natural slate.“Slate requires no additional treatment.”

To make its slate rainscreen cladding, dubbed CUPACLAD, Cupa Pizarras extracts slate from 20 quarries located in northwestern Spain, between the provinces of Ourense and León, home of the and biggest natural slate outcrops in the world. “Every slate produced for CUPACLAD has been handcrafted and selected by hand, and only flat, smooth slates are selected,” Rivas says.

Adaptable Design

Even with its ancient track record of being an efficient system for construction envelope purposes, slate rainscreen cladding systems are adaptable to varied design styles. Slate can be manufactured in a range of shapes including hexagons, waves, mosaics, and trapezoids, and they can be placed vertically, irregularly, and integrated with other materials like wood. Plus, there are options for visible and nonvisible fasteners.

“CUPACLAD systems are constantly evolving,” Rivas says. “We listen to architects and installers to make a better product every day.” Their openness to innovation is allowing architects to have an expanding choice of design options.

Dependable Installation

Slate as a standalone material can last up to 200 years on its own, and it can last more than 100 years as a rainscreen cladding. As slate is just the exterior part of a rainscreen, the aluminum profiles, insulation materials, and other flashing details will need some reviews from time to time. The system’s longevity also depends on some technical aspects based on climate, type of building, and installation methods.

Naturally durable and strong, slate rainscreen cladding is easy to install and is compatible with most typical building materials and types of insulation. With pre-drilled slate tiles in the CUPACLAD rainscreen, possible installation inconsistencies and overall installation times are further reduced.

“It is important that our experts can give advice during all the stages of the project,” says Rivas, “to ensure the most beautiful and efficient outcome.”

For more information about natural slate rainscreens, visit the CUPACLAD website.