Clay Walls: Using Earthen Plasters and Paints in Your Home

Clay walls beckon you to come closer—to see the subtle variations in color, to feel the textured surface, and to embrace the beauty of this natural and sustainable building material.

| November/December 2011

  • Clay plaster can be rough and tumble or smooth and subtle. American Clay's Porcelina line (shown in Tucson Gold) lets this room's strong architectural lines shine through.
    Photo Courtesy American Clay
  • Tierrafino’s Roman-Ochre and Iquitos-Green set a serene scene in this bedroom.
    Photo Courtesy Tierrafino
  • Based in Amsterdam and distributed in the United States through Hopper Finishes, Tierrafino offers clay plasters made from a mix of clays and colored sands. Djenne-Red lends warmth to this dressing room.
    Photo Courtesy Tierrafino
  • Adam Weismann and Katy Bryce, authors of Using Natural Finishes, use test panels in their studio to achieve ideal color and consistency. They recommend you do the same and test an area before beginning any job.
  • Natural clay plaster adds depth, texture and warmth to walls and creates a stunning background for weathered woods and industrial salvage. Shown in a custom blend of Sanibel Sunset and Nantucket Sand, American Clay's Loma line is made with reclaimed marble, sand and clay and has a matte finish.
    Photo Courtesy American Clay

Dig your hands deep down into the earth. Get beneath the dark layer of topsoil and into the rich subsoil, where the earth gets dense and sticky. Here you find clay, a plentiful raw material humans have been using throughout history to build and decorate structures around the world. Rudimentary clay plasters waterproofed our ancestors’ primordial structures. Refined versions covered the walls of well-to-do 19th-century European homes. Rich red clay was baked into bricks to form the shape of the humble adobes that dot the southwestern United States. Today we can take advantage of this healthy, sustainable, user-friendly material to warm up the walls of our homes.

“Clay is one of the most abundant raw materials available,” says Adam Weismann, coauthor of Using Natural Finishes. “It’s right under your feet—right now. You just have to know how to use it in a living space.” When mixed with water, natural fibers and aggregates, clay acts as a binding agent, adhering the malleable mix to walls. It can be manipulated into varied shapes and styles—clean lines for modern and traditional tastes or undulating curves for an organic feel. If you can get the materials from your own land (or from a friend’s), the cost is minimal, and sourcing locally conserves the energy that would otherwise be used for shipping. “It’s also extremely rewarding and visually pleasing when the building materials that create a structure are literally a part of their natural surroundings,” Weismann says.

Dig Deeper

Making your own clay plaster out of materials available onsite is an inexpensive, local option, but it’s not easy. Digging clay and creating the proper mix for use on walls can be a labor- and time-intensive endeavor. If you want to give it a go, see our recipe and instructions at the end of this article. If you’re in the market for clay walls that require less effort, purchasing a ready-made mix from a manufacturer such as American Clay is an easier route. Based in New Mexico, American Clay sources 72 percent of its materials from within 500 miles of its manufacturing site, and its pigments are made of naturally occurring oxides and minerals from the United States. Most of its plasters are shipped as 50-pound bags of powder, which you hand-mix with water and a packet of one of the company’s 42 colored pigments. At about $1 to $1.35 per square foot, it costs more than the DIY version but provides consistent, colorful results. Want the look of clay with even less work? Consider roll-on clay paints (see Resources), which offer the warmth of clay but aren’t as thick and textured as clay plaster.

When made without synthetic additives, natural clay plasters and paints are entirely nontoxic, making them ideal for people with chemical sensitivities, pregnant women, young children and anyone who wants a healthy home. Clay plaster walls’ thick thermal mass means they also help regulate temperature and humidity. “Clay is breathable,” Weismann says. “It can safely absorb and hold moisture vapor when humidity levels are high and then release it back into the atmosphere as the air becomes dry.” This provides a comfortable living space and helps prevent condensation and mold. In fact, museums and galleries have begun using clay plaster to help protect artwork and artifacts. 

Hands On

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