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What are the Best Tips for Sealing Basement Walls?

Matthew Brodsky
Matthew Brodsky

The basement of a house can add extra living space and comfort when it is finished and furnished. When the basement is cold and wet, however, it can often not even be fit to be a storage area. To dry the area, the key is to seal the basement walls and end seepage. The best tips for doing so include properly cleaning the foundation walls and other basement walls, removing any hazards during the process and allowing the walls to properly dry.

When sealing basement walls, the first step is to clean the area. This involves cleaning the basement walls entirely with a typical household cleaner. Some sealants used to waterproof basement walls might require a special cleaner in addition to or instead of this. Read the sealant's directions to find out. When cleaning, be sure to watch out for grease stains on the basement walls. These need to be removed and might require a detergent to do so.

Applying waterproof sealant is one of the final steps when sealing basement walls.
Applying waterproof sealant is one of the final steps when sealing basement walls.

Other things to look out for on basement walls include old paint, loose plaster or concrete, and residue salts from flood waters. Old paint can be removed by scraping it away, or with paint thinner or another chemical paint remover. Loose plaster should be chipped away and removed. Residue salt requires the use of a solution of muriatic acid.

The next step in the process of sealing basement walls is to fill in any cracks in the walls. After you have cleaned the walls and the cracks, the first step is to actually make the cracks larger. The cracks must be at least an inch wide with cut-in edges. This can be done with a ball peen hammer and a chisel. This is done to ensure that the cement can properly fill the space.

Powdered cement paints should be applied to wet basement walls.
Powdered cement paints should be applied to wet basement walls.

Hydraulic cement should be used to fill the cracks when they are ready. Overfilling will leave rough and uneven spots and should be avoided. It will take at least a week for the cement to dry fully before it's time to turn to sealing basement walls.

The final step in sealing basement walls is to apply the basement waterproofing sealant. There are two kinds. Liquid waterproofing sealant can be used only if the basement walls are entirely dry. Powdered cement paint must be applied to wet walls, and two tools are required to properly apply it to the walls. A roller or brush is required to apply the sealant, and a paint brush is used to tamp the sealant into less smooth areas of the basement walls. Applying a second coat is necessary for the best results.

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    • Applying waterproof sealant is one of the final steps when sealing basement walls.
      By: DyMax
      Applying waterproof sealant is one of the final steps when sealing basement walls.
    • Powdered cement paints should be applied to wet basement walls.
      By: Rob
      Powdered cement paints should be applied to wet basement walls.