Preventing Water Damage in Masonry Structures: Tips from the Pros

Masonry structures are known for their beauty, strength, and durability—but even the most well-built stone or brickwork is not immune to the damaging effects of water. At JNM Construction, a Knoxville-based construction company specializing in concrete, masonry, and excavation, we’ve seen firsthand how water infiltration can deteriorate masonry over time.

Whether you own a home with a brick façade, stone retaining wall, or custom masonry fireplace, protecting your investment from moisture should be a top priority. In this post, we’ll share expert tips for preventing water damage in masonry structures, tailored especially for Knoxville’s climate and terrain.

Why Water is the #1 Enemy of Masonry

Masonry materials—like brick, block, and stone—are porous by nature. That means they can absorb water during heavy rainfall, snow melt, or high humidity. If not properly protected, trapped moisture can lead to:

• Efflorescence (white powdery salt deposits)
• Cracking and spalling (flaking or chipping surfaces)
• Mold and mildew growth
• Freeze-thaw damage in winter
• Structural weakening over time

In Knoxville’s humid summers and freeze-prone winters, water management is essential to preserving your masonry.

Common Sources of Water Damage in Masonry Structures

1. Leaking Gutters and Downspouts

Improper drainage from your roof can cause water to run directly down your masonry walls or pool near foundations.

2. Poor Grading

If your yard slopes toward your house instead of away from it, rainwater may flow into the base of masonry walls or retaining structures.

3. Unsealed Masonry Joints

Mortar joints between bricks or blocks are highly vulnerable to cracking, which allows water to seep in.

4. Lack of Flashing or Weep Holes

These small but essential components allow water to escape walls or redirect it safely away. Without them, moisture stays trapped inside.

Pro Tips to Prevent Water Damage

1. Apply Masonry Sealers

Masonry sealants form a water-repellent barrier while still allowing the structure to breathe. These are especially important for:

• Brick exteriors
• Stone retaining walls
• Outdoor fireplaces

Recommended: Silane/siloxane-based breathable sealers, applied every 3–5 years.

2. Ensure Proper Drainage Around Structures

You want rainwater to move away from your foundation and masonry features—not toward them.

JNM Pro Tip: We recommend grading the land so it slopes at least 6 inches over 10 feet away from the home.

Also:

• Keep gutters clean and extend downspouts at least 4 feet from the foundation.
• Install French drains or swales where necessary.

3. Repoint Mortar Joints

Repointing involves removing deteriorated mortar and replacing it with fresh, waterproofed mortar. This prevents water from seeping into the wall.

Knoxville Consideration: Because of our region’s temperature swings, we use flexible mortar mixes that expand and contract without cracking.

4. Add Flashing and Weep Holes

Flashing redirects water away from vulnerable areas, and weep holes allow water trapped inside to escape.

Critical locations:

• Around windows and doors
• At the base of masonry walls
• Near chimneys

If your home doesn’t have proper flashing or weep holes, now is the time to correct it.

5. Maintain Masonry Chimneys and Fireplaces

Chimneys are exposed to the elements year-round, and water penetration is a common issue.

Protect your chimney by:

• Installing a chimney cap
• Sealing crown and mortar joints
• Checking flashing regularly

6. Repair Cracks Immediately

Small cracks may seem harmless, but they quickly grow when water freezes inside them.

At JNM Construction, we use professional-grade sealants and fillers to stop cracks in their tracks.

7. Keep Vegetation Away from Masonry

Plants and vines might look beautiful, but they trap moisture and their roots can penetrate joints.

Keep at least 1–2 feet of clearance between plant beds and masonry surfaces.

Knoxville’s Climate and What It Means for Your Masonry

Knoxville experiences high annual rainfall, humid summers, and cold winters—conditions that make water management even more important for long-term structural integrity.

Key Local Considerations:

• Freeze-thaw cycles in winter increase the risk of cracking.
• Heavy spring and fall rains can lead to standing water.
• High humidity contributes to mold and mildew growth.

JNM Construction uses climate-specific materials and techniques to help protect your home against these conditions.

How We Help at JNM Construction

Masonry Inspection Services

We offer professional evaluations of existing masonry structures, checking for:

• Cracks and erosion
• Failing mortar
• Inadequate drainage
• Missing flashing or weep holes

Preventative Maintenance

• Sealing and waterproofing
• Repointing and joint repair
• Drainage installation
• Structural reinforcement

New Construction and Renovation

Whether you’re building a new retaining wall, custom stone patio, or fireplace, we design with drainage and weather resistance in mind.

Bonus: We also handle excavation and concrete work, so every part of your outdoor project is managed under one roof.

FAQ: Homeowners Ask About Masonry Water Damage

Q: How often should I reseal my brick or stone surfaces?

A: Every 3–5 years, or sooner if you notice water absorption or staining.

Q: What is efflorescence, and is it dangerous?

A: It’s a white powdery deposit caused by water-soluble salts. While not dangerous, it indicates moisture problems.

Q: Can water-damaged masonry be repaired?

A: Yes, but early intervention is key. The longer water damage goes unaddressed, the more costly repairs become.

Q: What is the cost of waterproofing masonry?

A: Prices vary based on structure size, condition, and product used, but expect a range of $2–$6 per square foot.

Final Thoughts: Don’t Wait Until It’s Too Late

Masonry structures are built to last—but only if they’re properly maintained. Water damage can quickly reduce the value, appearance, and safety of your property. Fortunately, proactive steps and regular inspections can prevent the majority of these issues.

If you suspect a water problem or want to protect your masonry before issues arise, JNM Construction is here to help. As Knoxville’s local experts in concrete, masonry, and excavation, we bring the experience, tools, and local knowledge needed to keep your home safe and strong.