Chimney & Valley Flashing RebuildsReinforcing the Most Vulnerable Roof Joints
The intersections around chimneys, brick walls, and valleys are where most roof leaks occur. We install custom lead and copper flashing wraps to seal joints for the long term.
Why Choose NorthForge for Chimney & Flashing?
Custom Step Flashing
We weave individual step flashing tins under each shingle course along brick walls, ensuring water flows outward.
Mortared Counter-Flashing
We cut directly into brick mortar joints to lock in counter-flashing, sealing the top seam from water entry.
Cricket Installation
For wide chimneys, we construct wooden crickets (roof diversions) to direct pooling water around the structure.
Masonry Crown Waterproofing
We seal cracked concrete chimney crowns and apply siloxane water-repellent coats to porous bricks.
Deep-Dive: Rebuilding Chimney & Valley Flashing to Stop Persistent Leaks
Chimneys and valley intersections represent the most vulnerable points on a roof. These areas channel high volumes of water. Because brick chimneys are separate structures, they expand and contract at different rates than the roof deck. If the junction is sealed only with roofing tar or cheap metal sheets, the shifting roof will pull the joint apart, resulting in persistent leaks.
Our chimney flashing rebuild is a two-part system designed to handle this movement. First, we install step flashing. These are individual L-shaped metal cards woven underneath each shingle course along the side of the chimney, preventing water from getting under the shingles. Second, we cut a horizontal groove into the brick mortar joint and tuck in counter-flashing, which overlaps the step flashing from above. This allows the chimney and roof to shift independently without breaking the water seal.
We also construct wooden crickets behind wide chimneys. A cricket is a V-shaped diversion peak that sheds water and snow around the chimney structure, preventing pooling. We fabricate these flashing details from premium materials like pliable lead (which conforms perfectly to brick textures) or cold-rolled copper for long-term leak protection.
System Characteristics & Metrics
How We Execute Chimney & Flashing
Our rigorous, step-by-step installation process ensures quality that lasts.
Old Metal Removal
We pry out old shingle borders, tear off corroded flashing, and clear the chimney base.
Deck Prep & Ice Wrap
We check deck wood, rebuild framing if needed, and wrap the chimney base in self-adhering membrane.
Step Flashing Placement
We weave custom-bent step flashing metal sheets under each shingle course up the sides.
Mortared Counter-Flashing
We cut grooves into brick joints, tuck in counter-flashing, seal with mortar, and clean the site.
Premium Components We Install
We install quality roofing and siding products from trusted manufacturers, based on the needs, design, and specifications of each project.
16oz Cold-Rolled Copper
Flashing MetalCorrosion-resistant copper sheet custom cut for valleys and chimney wraps.
Custom-Bent Flashing Lead
Flashing MetalPliable lead sheets easily molded to seal brick texture profiles.
Self-Adhering Membrane
Waterproof ShieldRubberized asphalt base membrane sealing around nails.
Masonry Crown Sealer
Crown SealerElastomeric crown coat sealing cracks on concrete masonry crowns.
Frequently Asked Service Questions
NorthForge Exteriors
We coordinate inspections and project sites throughout MetroWest, Greater Boston, and Worcester County. Reach out to schedule a free on-site visit.
Free On-Site Estimates
No pressure, no obligation. We respond within one business day with clear next steps and a free inspection.
Emergency roof tarping and urgent exterior repair services are available, subject to scheduling and crew availability.