Stucco is one of the most ancient, well-beloved building materials still in use today. Its combination of looks, durability and ease of application makes it a great fit for many exteriors.

But just like any material on your exterior walls, it needs maintenance over time. Mold can dig in and change the color of your stucco, leaving green or brown patches that can be hard to deal with.

Stains will make your walls less attractive over time and lower the curb appeal of your building. They aren’t hard to fix, though. Here’s what you need to know.

Stucco vs. EIFS

First you need to know whether you’re dealing with stucco or EIFS, which is similar to stucco but can require a little more caution in cleaning. EIFS is made of insulation foam covered in an exterior stucco-like layer.

Knock on the exterior walls with your knuckles. If it makes a hollow sound, it’s probably EIFS. A wall that feels and sounds solid is stucco. You can also check by looking at the bottom of the cladding if it’s not below the grade. If it’s thicker than ¾ of an inch, it should be EIFS.

Stucco stands up to harder cleaning methods than EIFS because the outside layer is tougher. It doesn’t have the same insulation values, though, which makes EIFS a common choice for newer buildings.

Finding the cause

If you see streaks and stains from mold, mildew or other organic material, check to find the cause. Are your gutters leaking? Is water pooling on the outside of the building? Fixing the stain but not the cause just means you’ll have to come back and do the job again, usually when the problem has gotten worse.

Mold and mildew often thrive where plants grow close to the walls. Make sure your plants are trimmed and away from your building to avoid making areas where mold and mildew grow heavily.

Check your stucco or EIFS for chipping, flaking and tears while you’re at it. These can make mold problems worse as water can get in behind the surface and wreak havoc. Clean carefully and make repairs afterwards.

Choose a method

A pressure washer is often enough to get stucco clean, but be careful. If the pressure is too high you can strip away material, particularly with the softer EIFS. Start your pressure low and work up as needed to remove stains.

For bad stains, a mixture of water regular dish soap will often work. Oxygen bleach or regular chlorine bleach will work too. Just be careful with chlorine bleach near plants. A bristle brush will help you get out any stubborn areas.

Exercise caution and use the mildest cleaning method first, then work your way up if that doesn’t work.

Keeping your exteriors clean isn’t hard, but you have to know what you’re doing. If you have any questions, contact us at JK Industries. We specialize in exterior surfaces, and we’ll help you keep yours clean and structurally sound.