When roof flashing is installed near brick chimneys, walls, or masonry structures, it is typically “let into” (embedded into) the mortar joints to create a watertight seal. This involves cutting grooves into the mortar and embedding the flashing to ensure proper adhesion and prevent water penetration. If this critical step is skipped, the flashing may fail, leading to water leaks and potential damage.

1. Watertight Seal

• Embedding flashing into mortar joints prevents water from seeping behind the flashing and into the structure.

2. Secure Installation

• Flashing let into mortar joints is less likely to detach or shift due to wind, weather, or thermal movement.

3. Long-Term Durability

• Properly embedded flashing is better protected from wear and tear, ensuring it remains effective over time.

1. Improper Installation

• Contractors may skip this step to save time or due to lack of expertise.

• Incorrect tools or techniques may result in flashing being surface-mounted instead of embedded.

2. Aesthetic Concerns

• In some cases, installers avoid cutting into mortar joints to preserve the visual integrity of older masonry, sacrificing functionality.

3. Use of Adhesives Alone

• Some installations rely solely on adhesives or sealants to secure flashing, which are less reliable than embedding it into mortar joints.

1. Water Penetration

• Without being embedded, flashing can allow water to seep behind it, leading to leaks in the roof, walls, or interior spaces.

2. Detachment

• Surface-mounted flashing is more likely to loosen or detach over time due to wind, rain, or thermal expansion and contraction.

3. Shortened Lifespan

• Flashing not let into mortar joints is more susceptible to damage from weather and wear, requiring more frequent repairs or replacement.

4. Structural Damage

• Water intrusion can lead to rot, mold, and deterioration of surrounding materials, including masonry, wood framing, and insulation.

1. Inspection

• Check for signs of water intrusion, such as leaks, stains, or mold near the flashing.

• Look for gaps or loose sections of flashing along the masonry.

2. Temporary Fixes

• Use high-quality roofing sealant to seal gaps between the flashing and masonry as a short-term solution.

• Apply a waterproof adhesive to reinforce the flashing until proper repairs can be made.

3. Reinstall Flashing Properly

• Remove existing flashing and cut grooves into the mortar joints using a masonry grinder or chisel.

• Insert the flashing into the grooves and secure it with a waterproof sealant or mortar.

• Ensure the flashing overlaps and is properly angled to direct water away from the structure.

4. Install Counter-Flashing

• Add counter-flashing above the embedded flashing to provide an additional layer of protection against water infiltration.

1. Hire Experienced Professionals

• Work with contractors who have expertise in roofing and masonry to ensure proper flashing installation.

2. Specify Installation Requirements

• During installation or repairs, specify that flashing must be let into mortar joints to ensure a watertight seal.

3. Use Quality Materials

• Opt for durable flashing materials such as stainless steel or copper, which are less prone to wear and tear.

4. Inspect Work During Installation

• Monitor the installation process to ensure flashing is embedded correctly into the mortar joints.

• Persistent Leaks: If water infiltration continues, a professional roofer or mason should inspect and repair the flashing.

• Widespread Damage: If the surrounding masonry or roofing materials are compromised, a complete repair or replacement may be necessary.

• Complex Masonry Features: Flashing around chimneys, parapet walls, or decorative masonry requires specialized skills.

Flashing that is not let into mortar joints is a critical issue that compromises the waterproofing of your roof and masonry structures. Proper installation is essential to protect your home from water damage and ensure the longevity of your roofing system. If you suspect your flashing has been improperly installed, consult a professional to correct the issue and safeguard your home. Investing in quality materials and skilled workmanship will provide long-term protection and peace of mind.