Masonry Leak Detection & Repair
Finding where water gets in — and stopping it permanently.
Masonry leak detection is the process of systematically identifying where water is penetrating a masonry wall — and then repairing the root cause so it doesn't come back. McNamara Masonry Restoration brings over 36 years of masonry expertise to every leak investigation, using a diagnostic approach that traces the actual water path rather than guessing. We fix the source of the leak, not just the spot where water appears inside.
The Diagnostic Approach
Water is deceptive. It can enter your wall at the roofline and not show up inside until it reaches a window two stories below. That's why guesswork doesn't work — and why we follow a systematic diagnostic process.
- Exterior visual inspection — mortar joints, flashing, lintels, sealants, cap stones, and weep holes
- Interior damage mapping — documenting where water appears to trace likely paths
- Targeted water testing — isolating sections of wall to pinpoint entry points
- Root cause identification — understanding WHY water is getting in, not just where
- Repair recommendation — detailed plan addressing the actual cause, with clear pricing
Common Causes of Masonry Leaks
🧱 Deteriorated Mortar Joints
Mortar erodes over time, creating gaps where water penetrates. Repointing with properly matched mortar restores the weather barrier.
⚡ Failed Flashing
Missing or corroded flashing at roof-to-wall junctions, window heads, and through-wall locations allows bulk water entry.
🪟 Cracked Lintels
Steel lintels above windows and doors rust and expand, cracking the masonry above them and creating leak paths.
🔧 Failed Sealant
Caulk and sealant around penetrations, expansion joints, and window perimeters fails over time, opening water entry points.
🏔️ Cap Stone & Coping Failure
Cracked or loose cap stones on parapet walls and chimneys allow water to enter from the top of the wall — the worst location.
💧 Missing Weep Holes
Without weep holes, moisture trapped in the wall cavity has no exit path and builds up until it forces its way through.
Our Repair Arsenal
Once we've identified the root cause, we have the tools and materials to fix it right.
Mortar joint restoration with properly matched mortar
New through-wall and counter flashing at all critical junctions
Corroded steel lintel removal and replacement
Waterproof masonry coating with 10-year warranty
Elastomeric masonry waterproofing in multiple colors
Reset or replace cap stones with proper mortar bedding
Frequently Asked Questions
We use a systematic diagnostic process — not guesswork. We start with a visual inspection of the exterior masonry, looking for cracked mortar joints, failed sealant, missing flashing, and other common entry points. When the source isn't obvious, we perform targeted water testing to isolate the leak path. With 36+ years of masonry experience as McNamara Masonry Restoration, we've seen every type of leak and know where to look first.
Masonry leak investigations typically start with a diagnostic assessment, with repair costs varying based on the root cause. Simple tuckpointing or sealant repairs may run a few thousand dollars. More extensive issues involving flashing replacement, waterproofing, or structural repair will cost more. We provide a detailed assessment and clear pricing before any work begins — no surprises.
Masonry walls leak for several common reasons: deteriorated mortar joints that have cracked or eroded over time, missing or failed flashing at roof-to-wall junctions, cracked lintels above windows and doors, failed sealant around penetrations, and hydrostatic pressure in below-grade walls. The key is finding the actual entry point — not just the spot where water appears inside, which is often far from where it enters.
Masonry repair addresses the structural defects that allow water in — repointing mortar joints, replacing cracked lintels, installing proper flashing. Waterproofing applies a protective coating (like Thorolastic or Sherlastic) to create a secondary barrier. Often you need both: repair the root cause first, then add waterproofing as an extra layer of protection. We never just waterproof over defects.
In most cases, yes. Our diagnostic approach identifies the specific failure point so we can target the repair precisely. Full wall replacement is rarely necessary for leak issues. Targeted tuckpointing, flashing repair, lintel replacement, or waterproof coating application can resolve most masonry leaks permanently when the root cause is properly identified.
Yes — McNamara Masonry Restoration has over three decades of experience with commercial masonry, churches, and historic structures. These buildings present unique challenges: higher walls, more complex flashing details, historic mortar matching requirements, and preservation considerations. We have the equipment, expertise, and scaffolding capabilities to handle large-scale masonry projects.
We use Thorolastic and Sherlastic masonry coatings for waterproofing applications. These products are formulated specifically for masonry — they waterproof the surface, protect against staining, discoloration, and cracking, and come in a range of colors. Both products are covered by a 10-year transferable warranty.
When the root cause is properly identified and addressed, our masonry leak repairs last for years. All work carries our 10-year transferable warranty. The key is solving the actual problem — not just patching symptoms. That's the difference between a repair that lasts a season and one that lasts a decade.
Get Your Free Estimate
Tell us about your project and we'll provide a detailed assessment — no obligation.