Should I Seal My Brick? The Surprising Answer

Here's a surprise: sealing brick can sometimes cause more harm than good. The key is understanding the difference between film-forming sealers and breathable penetrating sealers.

Film-forming sealers (like many products at hardware stores) create a barrier on the brick surface. The problem? They trap moisture inside the brick. In Michigan's freeze-thaw climate, this trapped moisture causes spalling.

Breathable penetrating sealers work differently. They allow water vapor to escape while repelling liquid water. If you seal brick, this is the only type you should use.

Many well-maintained brick walls don't need sealing at all. Brick is naturally durable. If your mortar joints are in good condition and you don't have moisture problems, sealing may be unnecessary.

When sealing makes sense: high-exposure areas like chimneys, retaining walls with ground contact, below-grade foundation walls, and brick that has shown moisture problems in the past.

Never seal brick that's actively showing efflorescence. The seal traps salts inside, making the problem worse. First identify and fix the moisture source, then consider sealing.

New mortar needs to cure before sealing. Wait at least 28 days after repointing before applying any sealer. Sealing too soon traps moisture in uncured mortar and causes premature failure.

For patios and walkways, penetrating sealers help prevent staining and make cleaning easier. These horizontal surfaces benefit more from sealing than vertical walls.

If you're unsure whether your brick needs sealing, ask a masonry professional. We can assess your specific situation and recommend the right approach—which might be no sealer at all.