Dryvit is the brand name for an exterior insulation and finish system It's a home siding that looks like stucco but also functions as insulation. The manufacturer estimates that one in every 11 commercial buildings in the United States has a Dryvit exterior. It's becoming a popular choice for homes as well, as it requires less maintenance than conventional building materials. Dryvit still requires occasional cleaning, but this can be done easily by a small-business or homeowner.

Cleaning Dryvit Surfaces

Because Dryvit is an insulation system, the external coating is more susceptible to damage than traditional building materials. While the surface incorporates polymers that resist dirt, the manufacturer suggests cleaning your walls at least once every five years. Inspect where the surface panels meet window and door frames to make sure the sealant is not cracked or dried-out. Worn sealant could allow moisture into your walls. Use a soft-bristled scrub brush to apply a biodegradable detergent to the walls of your building. Test your cleaning compound on an inconspicuous spot to ensure it won't mar the exterior surface. Never use acidic cleaners or solvents such as mineral spirits on a Dryvit wall, as harsh cleaners could void your builder's warranty. Scrub gently, using an extension pole to reach second-story areas. Then use a spray nozzle and a garden hose to thoroughly rinse the detergent away. Use a stepladder to rinse from the top of the building downwards.

You may also use a power-washer to remove heavy dirt and grime. Avoid using high pressure: stay below 600 psi. Use a fan-tip nozzle held at a 45-degree angle to the wall and stay at least two feet back from the surface of the wall. Cold water alone is often enough to remove soil, though if your power-washer allows chemical injection you may add liquid dishwashing soap, followed by a rinse with a garden hose.

Dryvit materials are treated to resist mildew growth but in wet, shady areas mold or algae could still develop. Wet down the affected area then use a soft-bristled brush to scrub any growth away. Use a mixture of one part liquid soap, four parts chlorine bleach and 16 parts warm water. Rinse away any excess cleaner with a hose when you're done. Tar, asphalt, oil-based spray paints and some tree saps cannot be cleaned from the Dryvit surface and require a professional refinishing. Contact your builder or installer to make the appropriate repairs.