How To Clean Cinder Block Basement Walls [Plus Mold & Stain Removal]

A cinder block basement wall has a unique aesthetic. Keeping this distinct look requires the practice of regular cleaning. Now you’re wondering how you should clean your cinder block basement walls. We researched potential solutions and here’s what we found.

Cleaning cinder block basement walls often has different steps based on the main issue. For instance, mold removal for concrete blocks typically requires bleach. But routine maintenance may only need some materials and tools to complete the job efficiently. Regular cleaning for cinder block walls often demands these steps:

  1. Spray the wall with a pressure washer at 500 psi.
  2. Apply a TSP and water solution to the concrete block basement wall.
  3. Let the TSP mixture sit for approximately 15 to 20 minutes.
  4. Scrub the cinder block wall with a wire brush.
  5. Rinse the surface with warm or room temperature water.

Some households might also have to deal with efflorescence on their cinder block basement walls. Keep reading as we discuss the solutions to these issues in greater detail.

closed cell spray foam insulation in basement crawl space. How To Clean Cinder Block Basement Walls [Plus Mold & Stain Removal]

Can You Power Wash Concrete Blocks?

Power washing is generally an effective and fast method to clean concrete block walls, particularly in basements. It should only take about half a day to pressure wash large basement wall sections, which would otherwise take a full day or more if you use an ordinary hose or wire brush.

a man wearing hat and white shirt using high pressure cleaners to clean dirty wall

A 3,000 psi gas-powered power washer should suffice in eliminating dust and other filthy substances latched onto the concrete block wall. Users should also pay attention to the direction they’re using the pressure washer’s wand. Etching the concrete wall with the tool is important as arbitrarily waving it around will yield less than satisfactory results.

Find out more about the proper way of handling a power washer in cleaning concrete block walls by watching this video:

You can also read our post on how to clean a dusty concrete floor for you to gain more insight on the ways to make your basement spotless.

How Do You Clean Concrete Block Walls?

photo of a cinder block wall

Take note that cinder block basement walls don’t usually require deep cleaning until necessary. But regular maintenance can prevent serious issues from surfacing.

Next, make sure that you’re wearing a respirator or safety mask for this task. Dirt, dust, and other unclean particulates will become airborne while you’re cleaning the wall. Inhaling these substances will put you at risk of contracting health problems, such as coughing, wheezing, and other respiratory issues.

After preparing yourself for the upcoming cleaning operation, continue with the following guidelines:

What You’ll Need

  • Pressure washer
  • Pump sprayer
  • Trisodium phosphate (TSP)
  • Wire brush
  • Hose
  • Stepladder (optional)

Step-by-Step Guide

  1. Remove loose dust, muck, and grime from the cinder block basement wall with the pressure washer. Set it to 500 psi to prevent peeling the surface’s paint.
  2. Mix a cup of TSP (a natural degreaser) with a gallon of hot water. Place the solution in a pump sprayer and stir until the TSP dissolves.
  3. Spray the wall with the mixture, ensuring that you reach offending regions.
  4. Let the TSP solution sit for about 15 to 20 minutes.
  5. Use a wire brush to scrub the cinder block wall. Climb on a stepladder if necessary.
  6. Rinse the basement wall with a steady stream of water from a typical garden hose.
  7. Repeat steps 2 to 6 as many times as necessary to help remove stains.

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How Do You Remove Mold From Cinder Block Walls?

Mold is a problematic fungus that can grow on surfaces, such as cinder block walls, when in and around ideal propagating conditions. One factor that can make mold grow is moisture. In turn, removing dampness can help eliminate and prevent mold from developing on concrete block basement walls.

mold and mildew and peeling pain on a cinder block wall

As with any cleaning operation, it’s important to take precautionary measures to ensure your safety. For mold removal from cinder blocks, you need to protect your eyes, nose, and mouth. This fungus can enter your system through these areas, which can trigger health problems like asthma and allergy attacks.

Additionally, the effort needed to get rid of mold from cinder blocks depends on the fungus’ level of development. Fairly small growth patterns may not require more than an hour to clean. On the other hand, mold that took over large sections of cinder block basement walls may require more time and effort.

Heed the following instructions when you’re ready to tackle this operation:

What You’ll Need

  • Bleach
  • Water
  • Scrub brush
  • Mold preventer spray
  • Mold repellent paint (optional)

Step-by-Step Guide

  1. Dilute bleach in a container.
  2. Dip a scrub brush in the diluted bleach solution and apply it to the moldy surface.
  3. Let the mixture sit. Continue with the next step when the cinder block wall is dry.
  4. Apply mold preventer spray on the offending areas.
  5. If the cinder block basement wall doesn’t have paint, you may apply mold repellent paint to prevent the development of this fungus.

Check out this mold control spray on Amazon.

How Do You Remove Hard Water Stains From Concrete Walls?

Water can stain cinder block basement walls. Homeowners can use relatively common household items to clean hard water pigments.

The steps to potentially remove hard water stains on concrete walls are:

  1. Mix equal parts white vinegar with water and put the mixture in a spray bottle.
  2. Spray the offending areas and let the solution sit for 15 to 20 minutes.
  3. Wipe the mixture and stain away using a damp cloth or rag.
  4. Repeat steps 1 to 3 two or three more times to remove the pigments.
  5. If the white vinegar doesn’t work, proceed by mixing one part vinegar with three parts baking soda in a bowl or dish.
  6. Rub the paste on the offending areas and let it sit for about 15 minutes.
  7. Wipe the paste away using a damp cloth or rag.

How To Remove Efflorescence From Concrete Block Walls?

Efflorescence is a white, chalky, powder-like substance appearing because of moisture intrusion. Removal of this material is important for it can lead to structural harm to concrete block walls and a reduction of indoor air quality.

Take note that eliminating efflorescence begins by searching for the source of the moisture. Leaks and problems caused by heavy rainfall are examples of culprits that can lead to the appearance of this powdery material.

Focus on the areas around the moisture source for this project. Once found, you can proceed with the following instructions:

What You’ll Need

  • Sandblaster
  • Chlorine
  • Concrete densifier
  • Waterproofing paint

Check out this sandblaster kit on Amazon.

Step-by-Step Guide

  1. Use a sandblaster to remove the efflorescence from the concrete block wall.
  2. Apply chlorine onto the surface.
  3. Turn on a dehumidifier, heat pump, or basement furnace to dry the chlorinated wall.
  4. Apply a concrete densifier and let it cure. Make sure to read the manufacturer’s instructions to know the product’s precise curing time.
  5. Seal the concrete wall by covering it with waterproofing paint.

Learn additional details about this efflorescence removal project by watching the video below:

You might also be thinking about using other waterproofing techniques to prevent efflorescence from reappearing on your concrete block basement walls. If so, read our post on the costs of basement waterproofing to help you prepare for the overhead.

A worker wearing non-slip safety gloves is stacking concrete building blocks in a new residential basement foundation. How To Clean Cinder Block Basement Walls [Plus Mold & Stain Removal]

Final Words

It's advisable to use a power washer for the routine cleaning and maintenance of cinder block basement walls. Only use this tool at 500 psi, particularly if it's a painted surface. Other cleaning solutions are available to ensure your basement's concrete block walls remain spotless.

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