A sealer and a coating are very different from one another and there is often a lot of confusion that surrounds basement sealers. Use this article as a resource to explain the types of basement sealers so you can made a more educated buying decision.
Sodium and Lithium Silicate Sealers: Silicate based sealers, like sodium and lithium silicates, are Densifiers. They chemically react with the free lime and calcium in concrete to form CSH within the pores. Each type of sealer forms the exact same CSH structure, the difference between the two being how fast the structure is formed (lithium reacts faster). The CSH structure formed will partially fill in the pores of the concrete. The pores aren’t completely filled and the concrete will remain breathable. Through densification, the movement of water and moisture can be reduced.
The downfall to silicate based sealers is that the size of the CSH structure formed can’t be predicted, controlled, or even measured. The size of the structure will vary from pore to pore and is dependent on the amount of free lime and calcium present, the applied solids percentage, the porosity of the concrete, the amount of moisture present within the pores, and other factors. Multiple coats are required and a full reaction cycle can take up to 90 days.
Silane-Siloxane and Silicone Sealers: Silane-Siloxane sealers are silicone based sealers. They chemically react to form a hydrophobic barrier within the pores. The benefit to going with a Silane-Siloxane blend sealer is that it takes the benefits of each of the three types and eliminates the weaknesses. High solids (10% water based, 40% solvent based) will provide the best protection below the surface and on the surface.
Silane-Siloxane sealers are breathable. They can reduce moisture and will stop virtually all water absorption. They help to reduce dusting, mold and mildew, efflorescence, and moisture. When used in a basement application, moisture will be reduced. It can’t be stopped because Silane-Siloxane sealers are breathable, but moisture can be reduced as much as 40%.
Epoxy Sealers: Some epoxy coatings, like the ones manufactured by Foundation Armor, are designed to stop 10-24 LBS of moisture. If there is a requirement by flooring contractors to bring moisture down to below 3 LBS, an epoxy designed to hold back moisture is the most guaranteed solution.
Paint: Do your self a favor and avoid paint at all costs. Paint chips, peels, flakes, and doesn’t last. It is very sensitive to moisture and doesn’t hold a strong bond.
Sealing a Basement
There are a few steps that can be taken to reduce moisture. The products you require to seal your basement will be dependent on your budget, the source of water/moisture, and the amount of water/moisture penetration.
- Seal joints and cracks. The first step to stopping water and reducing moisture is to seal the joints (floor joints and coveseams), wall cracks and floor cracks. Some cracks need professional grade concrete repair products while others can get by with the use of a silicone grout, or similar product.
- Seal the walls and the floor. Moisture comes in through any concrete below grade. If you are looking for a preventative solution, or to reduce moisture, a sealer alone may be sufficient. If you need to bring moisture down to below a certain point, you may require a coating like the epoxy mentioned above.
- Install a drainage system. If large amounts of water enter into the basement during or after heavy rain storms, or in the Spring, consider installing a drainage system around the perimeter of the exterior to divert water away from the foundation/basement.
- Seal the outside. Use a water repellent Silane-Siloxane sealer to seal any exposed concrete on the exterior. Should water or snow be pushed against the concrete, it will be repelled and won’t absorb into the concrete and penetrate through into the basement.
- Armor SX5000
- Foundation Armor S2000
- Foundation Armor Epoxy