When rainwater gets absorbed into brick, it can cause damage not only with the brick, but to interior walls and floors as well. The damage isn’t always evident during the rainstorm, but as the water collects in the bricks and pushes through the brick, it will become apparent there is a problem within 3-5 days after the storm. It doesn’t have to be a heavy rainstorm with high winds to cause damage either. A light sprinkle can cause just as much damage as a heavy rainstorm if the rainwater hits the right spot on the brick, at the right time.
You can protect brick against rain water by sealing brick with a water repellent sealer. Water repellent sealers chemically react below the surface to form a hydrophobic barrier within the pores that causes water and other liquids to bead off the surface. When rain comes into contact with brick that has been sealed with a water repellent sealer, the rain water will bead off the brick and roll down the face of the brick to the ground. The brick will look dry during and after the rainstorm.
Brick Water Repellent Sealer Reviews:
- Eagle Natural Seal (average 4.0 star review)
- Armor SX5000 Concrete Sealer Review (average 4.8 star review)
- Siloxane PD Concrete Sealer Review (average 4.5 star review)
- Okon S-20 Concrete Sealer Review (average 4.0 star review)
- Thompson’s Water Seal Concrete Sealer Review (average 3.2 star review)
Under the category of water repellent sealers there are silane sealers, siloxane sealers, silane-siloxane sealers, and siliconate sealers. You don’t want to use siliconate sealers on brick because brick is dark and porous. Siliconate sealers are known to leave behind a white residue and will stain the brick. Silane sealers and siloxane sealers are great when used alone, but they each offer their own set of strengths and weaknesses. For example, siloxane sealers have a small resin and will penetrate deep into the brick. They will protect the brick from deep within the pores, but don’t leave much of a surface barrier. Siloxane sealers have a larger resin and are great for porous substrates like brick, but they are known to work better on the surface and don’t penetrate deep into the brick. Silane-Siloxane hybrid sealers are the best sealers to use because they work equally above and below the surface to protect the brick on the surface and from within the pores.
Not all Silane-Siloxane brick sealers are the same. There are low and high solids solutions. Low solids solutions typically contain 2-8% active materials while high solids solutions contain 20-40% active materials. Both types of Silane-Siloxane sealers will offer immediate gratification in terms of water repellency, but the higher solids solutions will perform better and last for up to 8 years longer than a low solids solution.
Sealing brick with a water repellent sealer is easy. First, make sure the brick is clean and free of anything that would prevent proper penetration or absorption of the sealer. If water or a pressure washer was used, allow the brick at least 24 hours to dry completely. Once the brick has had a chance to dry, use a roller or sprayer to apply the first coat of the water repellent sealer. If you used a water based water repellent, two coats should be applied and the second coat should be applied when the first coat is still wet. If you used a solvent based water repellent sealer, you want to wait until the first coat looks dry before applying the second coat. Solvent based water repellent sealers are typically more flexible and the second coat can be applied immediately after the first coat, or as long as a few days later.
There are many benefits to sealing brick with a water repellent sealer:
- Staining caused by rainwater will be reduced.
- Cracking, spalling, and pitting caused by the absorption of rainwater will be reduced.
- Mold and mildew caused by rainwater sitting in the pores will be reduced.
- Efflorescence brought to the surface by rainwater will be reduced.
In most cases, a water repellent sealer will stop rainwater from staining, damaging, and moving through brick, but in severe cases, other actions may need to be taken. Make sure the brick and grout lines are in tact, and that the brick doesn’t need to be re-pointed. If you are having issues with water leaking into your basement, make sure there is proper drainage set up.