5 Ugly Stains on Basement Walls: What Are They and How to Cope?

Unfinished basements aren't exactly eye candy, and for those of us who use our basements mainly for laundry and storage, looks aren't really important. That is, except for when ugly and suspicious stains begin to appear on our basement walls.

If you have ugly stains of any color on your walls or have noticed undetermined substances that are starting to peel, flake, fall, or ooze off of the walls, you're probably wondering if this could be a sign of other major problems. When basement wall stains appear, many homeowners begin to worry about mold and the implications it can have on their indoor air quality and health.

While not every basement wall stain is mold, all of them do have the same source and happen for the same reason as mold – water intrusion. When groundwater consistently infiltrates the porous concrete walls through capillary action, wall stains and related problems can occur. Therefore, the first step to correct any type of basement wall stain problem is to provide adequate foundation drainage in order to minimize the water infiltration. Unless you take every step to keep the soil surrounding the walls as dry as possible, those ugly stains will just keep coming back.

Before you attempt to clean up, it's important to recognize the different types of basement wall stains and know how to deal with them on an individual basis. Using the wrong products or procedures to get rid of wall stains can lead to more problems, and can sometimes pose undesirable and unnecessary health risks. Keep reading to find out more about the five most common types of basement wall stains!

1. Efflorescence

Efflorescence is commonly confused with mold. It is a white, powdery, sometimes glistening substance that appears on basement wall surfaces. Efflorescence is a loose mineral salt that is carried in with the water that infiltrates the concrete, being deposited on the walls during the process.

Although somewhat unsightly, efflorescence is harmless and poses no health concerns. It is, however, a sign of humidity. Basement humidity should be controlled, as it might cause more problems – including mold - to appear over time.

2. Reddish or orange (rusty) stains:

Rusty stains on the wall are a sign of iron ochre infiltration. Iron ochre is common wherever there are high levels of iron in the soil. Just like efflorescence, iron ochre is carried into the basement with the water that seeps in.

While not detrimental to human health, it can lead to many problems in your drainage systems by building up in pipes and drains and causing them to clog and fail. At Sure-Dry, we have a drainage system specially designed for areas with heavy iron ochre incidence.

Iron ochre stains are very stubborn, and they're almost impossible to clean. They will stain anything they touch, including carpeting, drywall, plastic, and other materials. There is no effective way to clean them from the walls, so your best approach is to cover them. 

3. Dark stains

Dark black or grayish stains on the wall are a sign of mold. Mold thrives in the presence of high humidity, warmth, and organic matter, on which it feeds. It's always warm enough in your home for mold to grow, even in the cold basement, and household dust carries enough organic matter to feed it.

The only thing you can do to stop mold growth in your basement is keep the relative humidity levels down, preferably at or below 60%. This can be accomplished with a good basement dehumidifier, like Sure-Dry's SaniDry Sedona basement dehumidifier. The SaniDry Sedona will not only keep mold under control, but it also has a powerful air filtration system that removes harmful particles like mold spores and dust mite pellets from the air you breathe.

Mold removal is a bit trickier than mold prevention and, according to both the EPA and the CDC, if the area infested is larger than 10 square feet (roughly 3 x 3 ft) you should not attempt to do it on your own without professional help. Smaller infestations can be cleaned with a bleach solution following the guidelines and safety measures provided by these agencies, which include using the proper ratio of bleach in the solution and wearing protective gear to avoid health problems.

4. Chipping and flaking materials

Many basement walls have coatings such as paint, waterproofing coats, sealants, or hydraulic cement, usually applied to either seal the basement walls or spruce them up. These coatings can and will eventually cave in as groundwater infiltrates the wall and the pressure builds underneath. When that happens, the coatings will bubble up, flake, or peel off of the walls – making for a very ugly and very messy basement with chips of paint all over the floor.

Paint and sealants should never be applied to basement walls. They all tend to fail over time, and when they do the cleanup is neither easy nor cheap and may involve messy or labor intensive procedures such as scraping, sanding, and power washing.

The best way to deal with this problem is to remove as much of the coating as you can and cover the walls with one of our basement wall protection products. And keep in mind, chipping coats should not be confused with spalling.

5. Spalling

Spalling occurs when the surface of the concrete itself, and not just the paint or the sealant, begins to crumble and flake. While it may appear similar to a chipping wall coat, spalling is often a much more extensive problem. The good news is, complete concrete replacement will not be necessary if the spalling is caught early enough.

Just like the other four problems we've discussed, spalling is due to water intrusion and the salts that it carries. When these salts expand, the concrete breaks and begins to flake away. The result is a bubbly, peeling wall surface.

Keep your basement dry to prevent water intrusion and wall damage

Once again, remember that these five common basement wall stains are all symptoms of a more significant problem. It's very important to fix the common source before you do anything else, so take action to stop the water intrusion into your basement before you tackle those ugly stains.

If you've noticed any of the above problems in your own basement, call Sure-Dry, and let us show you how to correct them once and for all! We can get rid of those ugly basement wall stains, and we can do it the right way so that they never come back. Call today and schedule your free, no-obligation cost estimate!