When it comes to protecting your home from water damage, proper flashing installation is essential—especially where a roof meets a vertical wall. This is where headwall flashing plays a crucial role. Headwall flashing is a critical component in roofing systems, designed to prevent water infiltration at the junction where the roof slopes up to meet a wall. There are several headwall flashing types, each suited to different roofing materials, architectural styles, and climate conditions. Understanding these types can help homeowners, builders, and roofing contractors choose the right solution to ensure long-term durability and weather resistance.
What is Headwall Flashing?
Headwall flashing is a waterproof material installed where a roof meets an upper vertical wall to stop any water seepage from seeping in between them, protecting homes against leakage that would otherwise occur between roof and walls and their joints. In doing this, headwall flashing helps stop moisture seepage that would otherwise leak between them, further protecting from:
✔ Water damage – Prevent leaks which could rot wood and ruin drywall for damage.
✔ Mold growth – Prevent moisture build-up behind walls.
✔ Structural issues – Shield the roof/wall connection against damage through headwall flashing.
Without proper headwall flashing, water can penetrate beneath shingles and siding leading to costly repairs.
Headwall Flashing Types:
There are various flashing types, each tailored specifically to various roofing materials and climate conditions. Here, we explore some of the more prevalent choices:
1. Step Flashing (Most Common for Shingle Roofs):
✅ Best for: Asphalt shingles roofs.
✅ Materials: Aluminum, copper or galvanized steel roofs might require different solutions.
✅ Installation: Layering L-shaped metal pieces under each shingle for water drainage.
✅ Cost: Range between $8-8-20 per linear foot (materials + labor).
Pros:
✔ High water-diverting efficiency.
✔ Compatibility with most roofing materials.
Cons:
✖ Labor costs installation.
✖ Must be properly sealed to prevent leaks.
Real-World Example:
According to research by the National Roofing Contractors Association (NRCA), proper Step flashing reduces leaks by 95% compared to unflushed joints.
2. Continuous Flashing (Apron Flashing):
✅ Best for: Metal roofs or low slope roofs.
✅ Materials: Aluminum, copper, or PVC.
✅ Installation: An extended metal strip bent into shape to cover the roof-wall joint can be easily.
✅ Cost: 5–5–15 per linear foot.
Pros:
✔ Faster installations require less work in terms of timeframe compared with step flashing.
✔ Utilizing long metal strips bent into fits more quickly provides seamless water barrier.
Cons:
✖ Not flexible when dealing with complex roof angles.
Experts Tip
Combine continuous flashing with peel-and-stick membrane for extra waterproofing.
3 .Counter Flashing (Used with Step Flashing)
✅ Best for: chimneys, brick walls.
✅ Materials: Made from Copper, Stainless Steel or Aluminum.
✅ Installation: Integrating directly into wall structure and overlying step flashing to cover.
✅ Cost: 10-10-25 per linear foot.
Pros:
✔ Extra layer of protection.
✔ Durability and longevity.
Cons:
✖ Professional installation required.
Case Study:
Historic brownstone buildings in New York utilize copper Counter flashing, with some installations lasting 80+ years.
4. Z-Flashing (For Horizontal Siding Joints):
✅ Best for: Vinyl, wood and fiber cement siding.
✅ Materials: Made out of aluminum or galvanized steel for horizontal joint flashing applications.
✅ Installation: Cover horizontal seams to block water.
✅ Cost: 3-3-12 per linear foot for installation.
Pros:
✔ Easy to install
✔ Prevents seeping water seeping behind siding.
Cons:
✖ Not suitable for vertical roof-wall joints.
Common Mistake:
DIYers often install Z-flashing incorrectly, which channels water behind siding rather than away.
5. Kick-Out Flashing (Diverts Water into Gutters):
✅ Best for: Roof edges near walls requiring diverting into gutters for drainage.
✅ Materials: Such as aluminum, copper or PVC.
✅ Installation: Redirecting water away from walls into gutters will save time.
✅ Cost: Piece should range between $15-15-30.
Pros:
✔ These systems prevent costly siding and foundation damages.
✔ Required by most building codes.
Cons:
✖ Many roofing projects tend to overlook.
Code Alert:
The 2024 International Residential Code (IRC) mandates kick-out flashing at roof-to-wall intersections.
How to Choose the Right Headwall Flashing?
| Factor | Best Flashing Type |
|---|---|
| Asphalt shingle roofs | Step flashing + counter flashing |
| Metal roofs | Continuous flashing |
| Chimneys/brick walls | Counter flashing |
| Vinyl or wood siding | Z-flashing |
| Roof edges near walls | Kick-out flashing |
Conclusion:
Selecting the proper headwall flashing types is vital in order to avoid leaks and protect your home from water damage. Key takeaways include:
🔹 Step flashing is best used on roofs made up of shingles.
🔹 Continuous flashing works great on metal roofs as shingle roofs.
🔹 Counter flashing is necessary and counter flashing essential.
🔹 Z-flashing protect horizontal siding joints.
🔹 Kick-out flashing prevents water damage to walls by sealing them against leaks ingress of rainwater ingress from rain gutters.
Employ a professional roofer when installing headwall flashing, as improper flashing installation may lead to major water damage.
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FAQs
How long does headwall flashing last?
Copper: 50+ years
Aluminum: 30–40 years
Galvanized steel: 20–25 years
PVC: 10–20 years
How can I install headwall flashing myself?
Simple flashing (such as
Z-flashing) may be DIYed; however, step and counter flashing should always be installed by professionals to prevent leaks.
What material makes for durable flashing?
Copper offers long-term durability at a higher cost, while aluminum provides a balanced mix of cost and lifespan.
How do I know my flashing is failing?
✔ Water spots on walls or ceilings
✔ Rust or cracks in metal flashing
✔ Loose or missing flashing pieces
Does homeowner insurance cover flashing repairs?
Only for damage caused by covered events (e.g., storms). Wear and tear is typically not covered.
What’s the average cost to install headwall flashing?
Expect costs between $500–$2,500, depending on roof size and flashing type.
Are different materials compatible for flashing?
No. Avoid mixing metals like copper and steel to prevent galvanic corrosion.
How often should flashing be inspected?
Inspect at least once annually or after major storms to ensure it remains secure and effective.
Is flashing required by building codes?
Yes, modern building codes require flashing at all roof-wall intersections.
What sealant works best when flashing?
Use high-quality polyurethane or silicone-based sealants for optimal performance and water resistance.
