Adobe walls were originally made with a mud and straw mixture baked by the sun to create a hard surface. This type of mixture is not very practical when it comes to interior design. There is an easy way to create the look of adobe walls using a joint compound mixture. Joint compound, when applied in a creamy mashed potato consistency, will create the look of adobe with more ease and a faster drying time than the sun-dried version.
Tape around the desired area with painter's tape. This includes the ceiling line and the top of the trimboard.
Sand the area, if previously painted, with 180- to 220-grit sandpaper until the shine disappears from the paint. The sandpaper creates small grooves in the paint to help the joint compound adhere.
Mix two batches of joint compound in separate 5-gallon buckets. Add enough water to create the consistency of creamy mashed potatoes. Add your colors to the mixture at this time. If the paint causes the mixture to become runny, add more dry joint compound.
Fill two drywall trays with the completed mixtures, putting one color in each tray.
Dip a plastic spatula in the lighter color and load a masonry trowel. Spread the mixture across the width of the trowel.
Press the loaded edge against your wall. Apply pressure while you move the joint compound over the wall to create a 1/4- to 3/8-inch thick swatch of compound. Reload and repeat the process until the wall is entirely covered. Imagine you are frosting a cake. Skip over the wall in places to add streaks if desired. As you are completing this process, blend the edges of each swatch into the previous swatches to create a more even look.
Add texture as you complete each 4-foot swatch if desired. Use a texture tool such as a texturing squeegee, window squeegee, notched trowel, corrugated cardboard or broom bristles. The texture is easy to remove immediately after you put it on the wall if you do not like it because the joint compound is still wet. Simply smooth the area with your masonry trowel to remove the texture, adding more joint compound to your trowel if necessary.
Load the masonry trowel with the darker color. Apply the darker color on top of the lighter color in small areas. Work the edges of the new swatches into the layers underneath. The use of two colors creates subtle shades within the faux adobe surface. Texture each area as you go if texture was added to the light color.
Allow the joint compound to dry completely. Knock off any unwanted ridges, points or bumps with a putty knife.
Seal the new faux adobe surface with a coat of water-based polyurethane sealer.