The short answer
Assess the Brick Condition
Before you apply anything, look closely at the brick and mortar. Check for cracks, spalling, or loose mortar joints. If the brick is crumbling or flaking, that is a sign of trapped moisture or freeze-thaw damage. You need to repair these issues first, or the sealer will not stick and water will still find a way in.
Water can also enter from above, such as through a damaged roofline or gutter. Walk around your home and see where water pools or runs down the wall. If you live in Euless, heavy spring storms can push water against brick for hours. Fix any downspout or grading issues before you seal the surface.
Clean and Prepare the Surface
Dirt, efflorescence, and old paint block sealers from bonding. Use a stiff brush and a masonry cleaner, or a pressure washer on a low setting, to wash the brick. Let the wall dry completely. Depending on the weather, that can take a few days. Sealing damp brick traps moisture inside, which leads to bigger problems later.
Check the forecast before you start. You want several dry days in a row. If the wall is shaded or the humidity is high, give it extra time to dry. A simple test is to tape a sheet of plastic to the brick overnight; if moisture collects on the inside, the wall is still too wet.
- Use a wire brush to remove loose mortar and dirt
- Rinse with clean water from the top down
- Let the wall dry for at least two sunny days
- Repair cracks with a masonry patching compound
- Re-point mortar joints that are missing or crumbling
Choose the Right Sealer
Not all sealers work for brick. You need a breathable, water-repellent product, usually a silane or siloxane based sealer. These penetrate the brick and let water vapor escape while keeping liquid water out. Avoid film-forming paints or acrylic coatings, because they trap moisture and cause the brick to deteriorate.
Read the label to check the coverage rate and whether it is suitable for vertical surfaces. Some products change the color of the brick slightly, so test a small, hidden area first. If you are unsure what type of brick or mortar you have, ask a local building supply store for guidance.
Apply the Sealer Evenly
Apply the sealer with a brush, roller, or low-pressure sprayer. Work in small sections so the product does not dry before you cover the area. Use a back-brushing technique to work the sealer into the pores. One coat is often enough, but a second coat may help on very porous brick.
Keep the sealer off windows, trim, and plants. Cover anything you do not want coated. Follow the manufacturer's instructions for drying time and reapplication. Most sealers last several years, but you will need to reapply them eventually. Recoating frequency depends on the product and how much weather the wall faces.
When to Call the Pros
If water has already soaked into the brick and interior walls, sealing the outside will not solve the problem. You may need structural drying and moisture mapping to see how far the water has traveled. The pros use specialized equipment to dry wall cavities and measure moisture levels before any sealer is applied. Policies vary, and your insurer decides what is covered, so check your policy to see if water damage repairs are included.
Also, if you suspect a leak inside the wall, such as from a pipe or flashing, locate and fix that first. Sealing the brick would only trap the water inside. In that case, a water damage inspection can help you find the source. After the wall is dry and repaired, you can proceed with waterproofing.
- Water stains or dampness on interior walls
- Efflorescence, the white powder on brick surfaces
- Cracks wider than a hairline or spalled brick faces
- Mold or mildew smell inside the home
- Recent heavy rain that left visible damp patches
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Call Now (817) 799-6732Frequently asked questions
Does waterproofing brick stop all water damage?
No. A sealer reduces water absorption, but it does not make the wall waterproof. Water can still enter through flashing, windows, or foundation cracks. You still need proper drainage and routine inspections. Sealing is just one layer of protection, not a permanent fix.
How often should I reapply brick sealer?
Most masonry sealers last 3 to 5 years, but it depends on the product, the brick's porosity, and how much sun and rain the wall gets. Check the surface each year for beading. If water soaks in instead of beading up, it is time to reapply.
Can I waterproof brick from the inside?
Sealing the inside of an exterior brick wall is usually a bad idea. It traps moisture in the brick and can cause spalling. Focus on the exterior surface and fix any drainage issues. If you have an interior dampness problem, find the source first.