Brick is very porous and for that reason, should only be sealed with a breathable sealer. A breathable sealer is a sealer that allows for moisture vapors to pass through the brick and the sealer. While a breathable sealer may slow down the movement of moisture, it won’t stop moisture from passing through, or trap it below the surface.

There are three types of sealers that are classified as breathable and those are silicate densifiers, water repellent sealers, and acrylic sealers.

As you can see, even though a sealer is considered to be breathable, the level of breathability will determine the life and performance of the sealer when applied to different types of brick.

Silicate Densifiers are chemically reactive sealers that form a crystal-like barrier within the pores. They are applied to bricks experiencing issues with dusting and deterioration caused by a weak surface or surface abrasion. Silicate sealers are great sealers, but they need to be applied in thin light coats. Over applying a silicate to brick will result in crystal formation on the surface and these crystals are near impossible to remove. Silicate densifiers are used on brick, but they aren’t the best brick sealer.

Best Sodium Silicate Brick Sealers:

• Armor S2000 Concrete Sealer Review (concentrated)
• RadonSeal Concrete Sealer Review (pre-diluted)
• Stone Technolgies X-1 Concrete Sealer Review (pre-diluted)
• Ashford Formula Concrete Sealer Review (pre-diluted)

Water repellent sealers are chemically reactive sealers that form a hydrophobic barrier within the pores that causes water and other liquids to bead off the surface. Water repellent sealers are the best brick sealer to use if you are trying to reduce deterioration and staining caused by water absorption. Water repellent sealers will also help to reduce mold, mildew, and efflorescence. Water repellent sealers are penetrating sealers and they will not change the look or color of the brick. The brick will look exactly as it did before being sealed. The best water repellent sealer for brick is a Silane Siloxane water repellent sealer. Silane Siloxane sealers help to fill up the large pore space inside of the brick. Siliconate water repellent sealers are a second type of water repellent sealer, but they aren’t designed for use on dark surfaces as they can leave behind a white residue.

Best Silane-Siloxane Brick Sealers:

• Armor SX5000 Concrete Sealer Review (average 4.8 star review)
• Siloxane PD Concrete Sealer Review (average 4.5 star review)
• DryWay Water Repellent Concrete Sealer Review (average 3.8 star review)

Acrylic sealers are used to enhance brick with a wet look, low gloss, or high gloss finish. They are also designed to leave behind a visible surface film that protects the brick against deterioration caused by surface abrasion. The problem with acrylic sealers is that while they are breathable, they are the least type of breathable sealer. If high amounts of sub-surface water or moisture are present, the acrylic will blush (turn white) or delaminate. This isn’t really an issue with concrete pavers so much as it is an issue with red clay brick pavers because red clay brick pavers are very porous. If you are unsure, apply to a test area first.

Best Acrylic Brick Sealers:

• Eagle High Gloss Sealer (average 4.6 star review)
• Armor AR350 Wet Look Sealer (average 4.8 star review)
• Armor AR500 High Gloss Sealer (average 4.9 star review)
• Enduraseal SB Acrylic Sealer (average 4.5 star review)