Basement Moisture

admin April 17, 2013 Waterproofing

When it comes to reducing moisture coming through a basement wall or floor, the solution will change depending on what you use the basement for. The products used to reduce moisture in an unfinished basement will vary greatly from the products you used when you plan on finishing your basement.

First, let’s go over the differences between a sealer and a coating. A penetrating concrete sealer is a breathable sealer designed to reduce the movement of moisture through the pores of the concrete. Breathable sealers can’t stop moisture. Certain coatings, like epoxy coatings, are not breathable and are designed to stop the movement of moisture through the concrete. A good rule of thumb to remember is that sealers are designed to reduce moisture and coatings are designed to stop moisture.

Which sealer is the best basement sealer to use to seal my basement floor and walls? Well, there are a few things to consider:

  • Is your basement unfinished? If your basement ins’t finished, and if you aren’t planning on finishing your basement, then you can use either sealer to reduce moisture or a coating to stop it.
  • Are you finishing your basement? If you are not finishing your basement, you can use a sealer to reduce moisture or a coating to stop it. If you are finishing your basement then you should consider a coating to stop moisture because if anything changes and moisture becomes present, the use of a sealer could let in enough moisture to cause mold growth behind the walls, or damage to the walls and floors. If you aren’t sure, consider a moisture test and go from there.
  • Is moisture a concern? If moisture isn’t a concern and you are looking to simply seal an unfinished basement for preventative reasons, then a penetrating concrete sealer is great. If you are worried about moisture, then why chance it? Sealers reduce, coatings stop.

Best Basement Wall and Floor Sealers

There are four primary types of sealers that can be used to seal basement walls and floors.

  • Sodium silicate concrete sealers: Sodium silicate sealers chemically react with the concrete to form calcium silicate hydrate (CSH) within the pores. The CSH structure formed will reduce the size of the pores with each coat applied. You can’t fully close the pores with a silicate because the CSH itself is breathable and has its own system of tracks and pores. Water and moisture can be significantly reduces with a silicate sealer, but never stopped. Silicate sealers are the most popular type of basement wall sealers.
  • Silane-Siloxane concrete sealers: Silane siloxane sealers chemically react to form a hydrophobic barrier within the pores. Silane siloxane sealers will help to reduce moisture by up to 2-4 LBS with two coats. Silane siloxane sealers are popular for basement sealing, but not as popular as silicate concrete sealers.
  • Acrylic Sealers: Acrylic sealers are breathable sealers that can help to reduce dusting and musty basement smells. They won’t stop water and can’t be used as a moisture barrier, but they do help to “freshen” up basement floors and walls. Acrylic sealers can’t be applied to concrete with high moisture levels so a moisture test, even if just a plastic test, should be done prior to applying an acrylic sealer.
  • Epoxy Coatings: Epoxy coatings, specifically ones rated for moisture mitigation, can stop moisture coming in through the concrete. 40% solids solutions are used on concrete with less than 10 LBs of moisture, and 100% solids solutions are used on concrete with 6+ LBS of moisture coming through.
    • Armor Epoxy Coating: Water based 2-part epoxy primer and top coat in one. Will reduce moisture in concrete, and protect the concrete surface against staining and deterioration caused by surface abrasion. A higher solids version is available for consumers that need more moisture protection, or want to apply the epoxy in a color.
    • Laticrete Epoxy: 2 part epoxy primer and top coat in one. Will reduce moisture in concrete and protect the concrete surface against staining and deterioration.

The Truth About Cracks

Penetrating sealers do not seal cracks, even hairline cracks. If water becomes present it will be able to move through the crack just as easily as it would if the crack had not been sealed with a penetrating sealer. Penetrating sealers are chemically reactive and produce a barrier within the pores. The size of that barrier is NOT determined by the sealer, it is determined by the amount of reactive materials in the concrete and/or the pore size. If you have a crack in your basement floor or wall then you should use the appropriate type of concrete repair products. Now, if you have a very tiny hairline crack that doesn’t let in water, and moisture isn’t a concern, then you can seal over the crack with a penetrating concrete sealer. It is important to understand however that sealers won’t stop water or moisture coming through a consistent opening in the concrete (i.e. crack).

Basement Sump Pumps

Sump pumps don’t stop water from coming in the basement, but they remove large amounts of water that has entered into the basement. If you are worried about basement flooding, or have issues with flooding in the past, you should consider installing a sump pump.

Basement Moisture Tests

If you still aren’t sure which product is best, start with a moisture test and let the moisture determine the solution.

 
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Author: admin