Introduction
Kickout flashing is a metal or plastic piece that redirects roof water away from a wall at a roof-to-wall transition. It helps keep water from getting behind siding and causing damage.
To install it, fit the kickout snugly against the wall framing and under the roofing edge, then fasten according to the material you’re using. Make sure water sheds away from the wall and into the gutter or flashing system. Check the product label, manufacturer instructions, and local rules for any requirements.
Key takeaways
- Kickout flashing directs runoff from roof to siding to prevent leaks.
- Verify compatibility with roofing, siding, and local codes before install.
- Use proper sealant and flashing lap details per manufacturer instructions.
- Prepare the wall edge and fascia to accept kickout without gaps.
- Secure all components, keep work area clear, and wear PPE during installation.
- Inspect from ground and ladder line for proper integration and water shedding.
Table of Contents
- Introduction
- Key takeaways
- What Is Kickout Flashing and Why It Matters
- Building Codes, Standards, and When It Is Required
- Types, Materials, and Material Specs Explained
- Tools and Materials Checklist
- Pre-Installation Preparation and Visual Checkpoints
- Step-by-Step Installation — Standard Asphalt Shingle Roof to Vertical Siding
- Installation Variations: Masonry, Metal Roofs, and Complex Rooflines
- Common Mistakes, Troubleshooting, and Inspection Checklist
- Conclusion
- FAQ
What Is Kickout Flashing and Why It Matters
Kickout flashing is a metal boot that directs roof runoff away from the wall where the roof meets siding. Its shape and placement are designed to bridge the gap between the roof edge and the vertical surface. The basic function is to prevent water from traveling behind siding and under roofing materials.
When kickout flashing is missing or installed incorrectly, water can intrude at the wall line, leading to rot, mold, and eventual exterior damage. The consequences can show up gradually, but they all trace back to misdirected runoff and failed water control. Always verify the manufacturer’s instructions for how your kit should be installed.
Definition and function
Kickout flashing is a crucial component at roof-to-wall transitions. It’s an L-shaped metal strip that diverts water from the roof edge, preventing it from running down the wall.
Unlike step or counterflashings which protect joints between different building materials, kickouts direct water away from walls to protect them from moisture damage.
Key point: Kickout flashing isn’t just about aesthetics; it’s a vital part of your home’s defense against water intrusion.
Failure modes and risks
Missing or improperly installed kickout flashing can lead to serious issues. Water running down walls can seep into gaps, causing rot, mold, and mildew.
You might not notice these problems immediately. They often hide behind siding or within wall cavities, growing worse over time. By the time you see signs, repairs can be costly and extensive.
Tip: Regularly inspect your roof-to-wall transitions for any signs of water damage to catch potential issues early.
Building Codes, Standards, and When It Is Required
Most jurisdictions and manufacturers expect kickout flashing at roof terminations where the roof meets a vertical wall or siding. Check the local code book or the authority having jurisdiction for specifics in your area. The goal is to ensure the flashing is integrated with both the roofing and wall assemblies as intended.
Inspectors commonly look for flashing at roof terminations against vertical walls, and many codes reference installation in accordance with manufacturer instructions. If you’re unsure, compare the installation with the product data sheet and your local rules before proceeding. Always document the code references you rely on for future inspections.
Relevant codes and best practices
To ensure your kickout flashing meets standards, consult these documents:
Local Building Code: Check for specific requirements in your area. Most codes mandate flashing at roof-to-wall intersections.
Roofing Manufacturer Instructions: Follow their guidelines for proper installation and placement of kickout flashing.
WRB (Water-Resistive Barrier) Guidelines: Ensure the WRB extends up the wall and is properly flashed to prevent water intrusion.
Typical locations inspectors check
Inspectors commonly look for kickout flashing at these critical points:
Exterior Wall Junctions: Where the roof meets exterior walls, especially at corners and intersections.
Eaves: At the overhanging edge of the roof where it meets the wall below.
Dormers and Other Roof-Wall Intersections: Inspectors will check for proper flashing where dormers or other roof features meet vertical walls.
Types, Materials, and Material Specs Explained
Common kickout flashing materials include aluminum, galvanized steel, copper, and PVC-coated options. Each has its own balance of durability, corrosion resistance, and ease of work in different climates. Consider how it will respond to sun exposure and heat cycles on your roof edge.
When selecting material, verify properties that affect compatibility with your roof and cladding, such as thickness, coating, and corrosion resistance. Ask about how it bonds with sealants and with the WRB system you’re using. If in doubt, check the label, product data sheet, or manufacturer guidance for your climate and materials.
Profiles and Prefab vs Field-Formed
Kickout flashings come in two main types: prefabricated and field-formed.
Prefab: These are factory-made, shaped to specific profiles. They’re easy to install, fit well, but may not suit complex roof lines perfectly.
Field-Formed: Metal sheets bent on-site. They offer a custom fit but require more skill and time for installation.
Compatibility and Corrosion Concerns
When different metals meet, galvanic corrosion can occur. This happens when one metal acts as an anode, sacrificing itself to protect the other.
Prevent it: Use compatible materials or add protective barriers like tape or paint between them.
For instance, don’t mix aluminum and copper directly. Always use a barrier or ensure they’re not in direct contact.
Tools and Materials Checklist
Assemble a practical kit: a snips or shears suitable for the flashing material, a hammer or crimping tool, sealant compatible with roofing and siding, and fasteners of the correct type for the substrate. Don’t forget lath or a backing under the edge if your wall requires it.
Include safety gear such as gloves, eye protection, and a stable ladder or scaffolding. Before starting, verify inventory and ensure all parts match the roofing and siding materials you’re tying together. If you’re unsure about fastener type, consult the product instructions or manufacturer recommendations.
Essential tools
Before you start, check off this list to ensure you have everything needed for a smooth installation.
- Snips: For cutting metal. Get both straight and tinsnips for different cuts.
- Seamer: To bend and shape metal flashings as needed.
- Hammer: For tapping down fasteners and shaping metal.
- Caulk gun: To apply sealants and adhesives.
- Fasteners: Nails, screws, or other fasteners that match your siding and roofing materials.
- Tape measure: To ensure accurate cuts and placement.
- Level: For checking the horizontal alignment of your flashing.
- Chalk line: To mark out cutting lines on metal.
Quick rule: Having the right tools saves time and prevents mistakes. Don’t skip this step.
Materials and sealants
Use this checklist to gather all necessary materials before starting your kickout flashing installation.
- Kickout flashing: Pre-formed or field-formed, matching your roofing and siding materials.
- Underlayment: Ice and water shield or felt paper, depending on your roof type.
- Fasteners: Nails, screws, or other fasteners that match your chosen flashing material.
- Sealant/Adhesive: Appropriate for your flashing material (e.g., butyl tape for metal).
- Roofing cement: For securing the top of the flashing to the roof.
- Siding material: Matching siding pieces or trim for finishing the kickout.
- Drip edge: To prevent water from getting behind the flashing at the bottom.
- J-channel or corner trim: For finishing the sides of the kickout.
Quick rule: Using compatible materials and sealants prevents leaks and ensures longevity.
Pre-Installation Preparation and Visual Checkpoints
Start with a thorough visual check of the roof deck, shingles, WRB, and siding terminations. Look for loose or damaged shingles and compromised WRB spots that could impact flashing performance. Address any obvious rot or soft spots before installing the kickout.
Ensure the substrate is flat and dry, with any uneven areas corrected. Confirm WRB continuity at the wall edge and ensure the siding is properly backed to receive the flashing. If anything looks suspect, repair or replace before you proceed.
Assessing the intersection and substrate
Before installing new flashing, use this checklist to inspect the roof-to-wall intersection. This will help you identify any issues that could lead to costly rework or water damage.
- Check for rot at the intersection: Look for soft, crumbly wood or discoloration. Use a screwdriver to poke the area; if it’s soft, there’s rot. What goes wrong if you skip this: Water will continue to seep in, causing further damage and potentially leading to structural issues.
- Inspect sheathing condition: Check for missing, damaged, or loose sheathing. Tap it with a hammer; if it sounds hollow or feels weak, replace it. What goes wrong if you skip this: Inadequate sheathing can’t support flashing properly and may lead to leaks.
- Measure slope of the roof: Use a level to ensure the roof slopes away from the wall at least 1/8″ per foot. What goes wrong if you skip this: Improper slope can cause water to pool and leak into your home.
- Check for proper flashing overlap: Ensure existing flashing overlaps the roofing material by at least 2 inches. What goes wrong if you skip this: Inadequate overlap allows water to get behind the flashing and cause leaks.
- Inspect drip edge: Make sure there’s a drip edge along the roof’s lower edge to direct water away from the building. What goes wrong if you skip this: Without a drip edge, water can run down the sides of your home and cause damage.
- Check for proper ventilation: Ensure there are no obstructions in the roof’s overhang that could trap heat and moisture. What goes wrong if you skip this: Improper ventilation can lead to ice dams, mold growth, and structural damage.
- Look for signs of animal intrusion: Check for nests, droppings, or other signs that animals may have entered the roof. What goes wrong if you skip this: Animals can cause damage to your roof and bring pests into your home.
- Verify attic insulation: Ensure there’s adequate insulation in the attic to prevent ice dams and keep your home energy-efficient. What goes wrong if you skip this: Insufficient insulation can lead to heat loss, increased energy bills, and potential water damage.
Quick rule: Always address any issues found during the inspection before installing new flashing. This will help ensure a durable, long-lasting repair.
WRB, Underlayment, and Siding Tie-In
Use this checklist before installing siding to ensure proper integration with the weather-resistant barrier (WRB) and underlayment. This will help maintain a continuous water shedding plane.
- Check WRB laps: Ensure all WRB layers overlap by at least 4 inches. Check for any tears or punctures.
- Inspect underlayment: Make sure the underlayment is flat, secure, and free of wrinkles. Check that it extends beyond the WRB by at least 2 inches.
- Verify siding starter course: Ensure the siding’s starter course is installed correctly, covering the bottom edge of the WRB and underlayment.
- Check siding laps: Confirm that each row of siding overlaps the one below it by at least 1 inch. Check for any gaps or misalignments.
- Inspect corner trim: Ensure corner trim is installed properly, covering both sides of the WRB and underlayment at corners.
- Check window/door flashing: Verify that all windows and doors have proper flashing in place behind the WRB to prevent water intrusion.
- Inspect siding nailing fins: Ensure siding’s nailing fins are properly aligned with the underlayment and nailed securely. Check for any gaps or misalignments.
- Verify drip edge at eaves: Confirm that a drip edge is installed at the eaves to direct water away from the WRB and underlayment.
Quick rule: Always remember: “Water should never be allowed to wick or migrate behind your WRB.”
Step-by-Step Installation — Standard Asphalt Shingle Roof to Vertical Siding
Begin with layout marks to position the kickout so runoff is directed away from the wall when shingles sit over the edge. Cut the flashing to fit the roof edge and test fit before sealing. Secure with fasteners appropriate for the substrate, keeping the flashing tight against the wall.
Seal the joints with a compatible sealant, then continue with the shingle installation, maintaining proper overlaps and WRB integrity. Finish with trim or siding to integrate the flashing into the wall assembly. Follow the manufacturer’s sequencing guidance for the best results and leak protection.
Step-by-Step Installation Process
The following steps guide you through installing kickout flashing from a standard asphalt shingle roof to vertical siding, ensuring proper water management and maintaining shingle overlaps.
- Preparation: Inspect the area for any damage. Ensure your safety with appropriate gear like harnesses on high roofs.
- Measure and mark: Determine where you’ll place the flashing. Mark it out using a chalk line or pencil.
- Cut the underlayment: If needed, cut the roofing felt or underlayment to accommodate the flashing.
- Install the flashing: Position the flashing at your marks. Secure it with nails or screws as per manufacturer’s guidelines.
- Install shingles: Place shingles up to and over the flashing, maintaining proper overlap with existing shingles.
- Check for leaks: After installation, use a garden hose to simulate rain conditions. Check for any leaks around the flashing.
- Cleanup: Remove any debris or nails left behind after installation.
Layout, fit, and securing the flashing
Start by measuring the area where you’ll install the flashing. The flashing should extend beyond the siding to direct water away from it.
If necessary, trim or bend the flashing to fit your specific installation. Use tin snips for this task, ensuring clean cuts.
Secure the flashing using nails or screws. Place fasteners every 6-8 inches along the length of the flashing. Ensure they’re close enough to prevent the flashing from buckling but not so tight that it causes stress on the material.
Integrating with shingles and drip edge
Begin installing shingles up to the flashing. The first course of shingles should cover the top edge of the flashing, providing a second layer of protection.
Install drip edge along the eaves before placing the starter strip. This helps direct water away from the fascia and prevents it from getting behind the siding.
The starter strip goes on next, covering the bottom edge of the shingles and providing a base for the rest of your roofing. Ensure it overlaps the top edge of the flashing by at least 2 inches.
Final seals and siding termination
Once the shingles are in place, apply a bead of sealant along the top edge of the flashing. This helps prevent water from getting behind the siding.
Bedding the siding over the flashing is crucial. Apply a generous amount of caulk or sealant to the top edge of the flashing before installing the siding. This creates a tight seal, preventing any water intrusion.
After installing the siding, apply a finish coat as per manufacturer’s instructions. Ensure it covers the seam between the siding and flashing, providing an extra layer of protection against moisture.
Installation Variations: Masonry, Metal Roofs, and Complex Rooflines
On brick or stone walls, adapt the flashing profile to fit the flush surface and use appropriate anchors and sealants for masonry. For metal roofs, use flashing parts that match the metal profile and ensure clean, continuous sealing. In complex rooflines, plan for multiple planes and dormers where the wall is penetrated by flashing at several angles.
Different substrates require different attachment and sealing methods, so check the substrate type and use compatible fasteners and sealants. If you’re unsure, reference the substrate manufacturer instructions or consult the local building codes for guidance. Always test fit multiple sections before final sealing.
Masonry walls and counterflashing
When dealing with masonry walls, you’ve got a few options for your kickout flashing. You can embed it directly into the mortar joints or use reglets – those are metal strips that go into the wall.
If embedding: Make sure to cut the flashing long enough to go at least 8″ into the joint. Use a hacksaw for straight cuts, and be careful not to damage the surrounding bricks or stones.
With reglets: Install them before laying the wall, then slide your flashing in once the mortar’s set. Seal with a masonry-appropriate sealant.
If you’re doing any repointing work after installing, be careful not to damage the flashing. You might need to temporarily remove it and reinstall once you’re done.
Metal roofs and standing-seam detail
For metal roofs, especially those with standing seams, avoid penetrations at the seams. You don’t want to compromise your roof’s integrity.
Tie-in method: Use a clip or screw that goes through the seam’s lip and into the flashing. This way, you’re not piercing the seam itself. Seal with an appropriate metal roof sealant.
Direct water away from the wall. On standing-seam roofs, this might mean using a wider flashing or adding a diverter at the low point of the seam.
Always follow the manufacturer’s guidelines for your specific metal roofing profile.
Complex junctions and multiple rooflines
When you’ve got offsets, intersecting valleys, or stepdowns, a single kickout might not cut it. You’ll need to get creative.
Offsets: Use a stepped flashing here. It’s like a regular kickout but with an extra bend to follow the offset. Seal at both bends and where it meets the wall.
For intersecting valleys, you might need multiple kickouts, one for each valley. Make sure they overlap properly to direct water away from the wall.
Stepdowns: Use a combination of kickouts and step flashing. The key is to create a path for water to follow off the roof and away from the wall.
Common Mistakes, Troubleshooting, and Inspection Checklist
Common errors include incorrect slope or angle, poor integration with the WRB, and using the wrong material for the substrate. Fixes start with rechecking the angle, resealing joints, and replacing incompatible flashing. Revisit each step to ensure continuity with the wall assembly.
Use a concise inspection checklist for rainy weather: verify water shedding away from the wall, confirm seams are sealed, and look for any gaps or misalignments. During a rain test, observe for any active leaks and address them promptly. If in doubt, pause and verify with product instructions or local requirements before finishing the job.
Typical installation errors and fixes
Use this checklist during or after installation to catch and fix common mistakes.
- Improper slope: Flashing should slope downwards at 1/4 inch per foot. Check with a level. If not, water can pool and leak.
- Poor WRB integration: Ensure flashing overlaps the water-resistive barrier (WRB). Inspect overlap length. Without this, water can bypass the WRB.
- Wrong material: Check if you’re using correct flashing type (e.g., step, apron, or counter). Using wrong type can lead to leaks.
- Inadequate sealing: Inspect all joints and seams for proper sealing. Unsealed areas allow water entry.
- Corroded sections: Check for rust or corrosion, especially at edges. Replace if found to prevent further damage.
- Loose flashing: Tighten any loose screws or nails. Loose flashing can flap in wind and cause leaks.
- Incompatible materials: Ensure flashing doesn’t react with nearby materials (e.g., aluminum near concrete). Reaction can cause corrosion and leaks.
- Incorrect drip edge tie-in: Check if drip edge is properly integrated. Without this, water can run behind siding.
Quick rule: Always double-check your work. Better to find mistakes now than later when it’s raining.
Maintenance schedule and seasonal checks
Perform these checks regularly to keep your flashing in top shape.
- Spring inspection: Check for any damage or blockages after winter. Remove debris to prevent water buildup.
- Summer heat check: Inspect sealants for signs of cracking or drying out. Reapply if necessary to maintain flexibility.
- Fall preparation: Ensure all joints and seams are sealed before winter. This helps prevent ice dams and leaks.
- Winter inspection (during thaw): Check for any water stains or leaks after snow melts. Address any issues promptly to prevent further damage.
- Corrosion check: Inspect for rust, especially at edges and joints. Replace if found to extend service life.
- Siding inspection: Check siding around flashing for signs of water intrusion. This can indicate a leak in your flashing system.
- Roof inspection: Ensure roof is in good repair and not causing water to flow over flashing. A damaged roof can lead to flashing leaks.
Quick rule: Regular maintenance extends the life of your flashing and keeps your home dry.
Conclusion
Kickout flashing is the small detail that protects your roof line from leaks, prevents rot, and keeps the look clean. Do it right, and you save time, money, and headaches down the road.
Check in plain terms: verify the correct flashing type and material for your roof and siding, confirm it is installed with proper slope and seal, test fit everything in a dry, calm window, then seal and fasten in the order your project requires, from flashing base to siding penetration, and finally do a live water test after it’s dry. Do it in that order and document any deviations before you commit to permanent sealants or caulks.
Two common mistakes to avoid are skipping the pre-install visual check and rushing through the transitions without matching the flashing to the siding profile. Don’t ignore building codes or local standards, and never work on a roof in wet, windy, or icy conditions. Always wear proper PPE, use tested materials, and verify compatibility before mixing products or making penetrations.
If the job involves masonry, a metal roof, or a complex roofline, or you’re unsure about the flashing’s fit to your specific wall profile, call in a professional. Safety and a correct seal are not negotiable. With careful planning and steady hands, you’ll have a solid, durable finish that protects your home and looks sharp. Stay deliberate, stay safe, and finish strong.
FAQ
When should I install kickout flashing on a roof-to-wall transition?
Install it at the first sign of water running from the roof edge toward the wall. If you’re retrofitting, plan to add it where water may shed from shingles onto the siding or flashing. Check manufacturer instructions for any specifics on your materials.
How do I tell if my kickout flashing is installed correctly?
Make sure the flashing is sloped toward the wall and extends behind the siding or weather barrier. It should be continuous and fastened securely with proper sealant or fasteners per the product instructions. Look for a clean seal where the roof and wall meet.
What are the most common mistakes to avoid with kickout flashing?
Avoid omitting the kickout entirely, under‑driving fasteners, or using sealant as the only barrier. Don’t let the flashing sit flat against the siding without proper clearance or a proper drip edge. Always follow the manufacturer’s installation steps for your materials.
What maintenance or inspection should I do after installation?
Inspect after heavy rain or wind for any leaks or gaps around the flashing. Look for rust, loose fasteners, or torn sealant and address promptly. Refer to product instructions or local guidelines for recommended inspection intervals.