Did you know, according to the 2022 Home Improvement Report by NerdWallet, about 39% of American homeowners prefer to do DIY roofing projects by themselves?
If you have landed here, then you’re probably one of them. It also says your search for how to install flashing on corrugated roof is over!
Flashing a corrugated roof involves installing protective material in vulnerable areas to prevent water infiltration. The flashing is strategically placed along the roof’s edges, ridges, valleys, and penetrations, such as chimneys or skylights.
In this 2023 updated guide, I will take you through the step-by-step guide for installing flashing on a corrugated roof and introduce a detailed buyer’s guide for corrugated roof flashings.
How to Install Flashing on a Corrugated Roof?
Installing flashing is crucial in ensuring the durability and waterproofing of a corrugated roof, preventing water intrusion, and safeguarding vulnerable areas.
Here’s a comprehensive guide on properly installing flashing on a corrugated roof for a professional and watertight result.
Step 1: Measure and Cut Flashing
- Start by determining the length of the section on the roof where the flashing will be placed.
- Use a tape measure to measure the distance accurately.
- Ensure that the flashing will cover the desired width of the corrugated roof, providing sufficient coverage for the intended purpose.
- It’s important to include a slight overlap on each end of the flashing when measuring the length.
- This overlap ensures a proper seal and prevents water infiltration.
- Typically, a 2-4 inch overlap is recommended.
- Mark the dimensions on the flashing material using a tape measure or straightedge. Make precise markings to ensure accurate cutting.
- Using tin snips or shears specifically designed for cutting metal or roofing materials, carefully cut the flashing along the marked lines.
- Use a straightedge or ruler to guide the cutting tool for better accuracy.
- After cutting, smooth out any sharp or jagged edges using a file or abrasive material.
- This helps prevent injuries during installation and ensures a proper fit.
Required Tools
- Tape measure
- Straightedge or ruler
- Marking tool (e.g., pencil or marker)
- Tin snips or shears designed for cutting metal or roofing materials
- File or abrasive material for smoothing sharp edges
Step 2: Position and Align the Flashing
- Carefully place the cut piece of flashing onto the roof, positioning it in the desired location where it will be installed.
- Ensure that the flashing covers the intended width of the roof and aligns with the corrugations.
- Leave a small gap between the flashing and any adjacent structures, such as walls, chimneys, or other roofing elements.
- This gap allows for the natural expansion and contraction of the materials due to temperature changes.
- Take a moment to double-check the alignment and positioning of the flashing.
- Verify that it is centered over the desired area and properly aligned with the corrugations of the roof.
- Pay attention to ensure that the flashing is straight and not crooked or misaligned.
- If the flashing is not aligned correctly or centered, carefully make any necessary adjustments.
- Gently move and reposition the flashing to achieve the desired alignment and positioning.
- Confirm that the flashing fits well within the designated area and does not extend beyond the edges of the roof or interfere with other components.
- This step ensures that the flashing will function effectively in diverting water and protecting the roof.
Required Tools
- Level
Step 3: Fasten the Flashing
- Begin the fastening process at one end of the flashing.
- This ensures a systematic approach and helps maintain alignment throughout the installation.
- Select roofing screws or nails that are suitable for the type of flashing material and the roofing surface.
- Position the fasteners in the flat area of the flashing above the corrugations.
- This helps secure the flashing without puncturing the corrugations themselves, which could compromise their structural integrity and water resistance.
- Use a power drill or impact driver to drive the fasteners through the flashing and into the roof’s underlying structure.
- This ensures a strong and reliable connection.
- Apply sufficient force to secure the flashing without overtightening or damaging the materials firmly.
- Place the fasteners approximately 6 to 12 inches apart along the length of the flashing.
- This spacing provides adequate support and stability for the flashing, helping to prevent it from lifting or becoming loose during extreme weather conditions.
- Ensure that the fasteners are driven consistently and uniformly.
- This helps maintain a neat and professional appearance while ensuring the flashing is securely attached to the roof.
- If the flashing material is particularly rigid or brittle, pre-drilling pilot holes may be necessary to prevent cracking or splitting.
Required Tools
- Roofing screws or nails
- Power drill or impact driver
Step 4: Seal the Flashing
- Choose a roofing adhesive or sealant compatible with the flashing material and the roofing surface.
- Opt for a high-quality product that offers durability and weather resistance.
- Using a caulking gun or suitable applicator, apply a continuous bead of sealant along the edges of the flashing.
- Start at one end and work your way around, ensuring coverage along the entire length of the flashing.
- Pay special attention to areas where the flashing overlaps with the roof or meets other surfaces.
- Apply sealant along these areas to create a watertight seal.
- Also, focus on joints and corners where water may have a higher chance of penetration.
- Apply the sealant consistently and evenly, creating a continuous bead of the desired thickness.
- This helps ensure an effective seal and prevents water from seeping through gaps.
- Use a putty knife or a caulking tool to smooth out the applied sealant.
- This helps create a neat and uniform appearance while ensuring that the sealant is properly pressed against the flashing and the roof.
- Thoroughly inspect the sealant for any gaps or areas that may require additional application.
- Look out for any visible openings or areas where the sealant may not have fully filled the gap.
- Using a clean cloth or rag, carefully wipe away any excess sealant that may have squeezed out during the application process.
Required Tools
- Roofing adhesive or sealant
- Caulking gun
- Putty knife or caulking tool
- Clean cloth or rag for wiping away excess sealant
It’s essential to follow proper safety precautions and consult with a professional roofer or contractor if you need clarification on any part of the installation process.
Types Corrugated Roof Flashings – Buyer’s Guide
There are several types of flashings used for corrugated roofs. The specific type of flashing you choose will depend on your project’s specific needs and requirements.
Here are some common types of corrugated roof flashings:
Ridge Flashing
Ridge flashings play a crucial role in maintaining the integrity of a corrugated roof by creating a watertight seal at the highest point of the roof, which is the ridge.
Their primary function is to prevent water from entering the roof along the ridge line and causing leaks or damage to the underlying structure.
Material
Ridge flashings are commonly made of durable and weather-resistant metals such as aluminum or steel.
These materials offer excellent strength, longevity, and resistance to corrosion, making them suitable for long-lasting protection.
Shape and Profile
Ridge flashings are specifically designed to match the corrugated profile of the roof.
They are formed in a way that aligns with the shape and contours of the roof’s corrugations, ensuring a proper fit and optimal coverage.
Installation
Ridge flashings are typically installed by placing them over the roof’s ridge and aligning them with the corrugations. They are secured in place using appropriate fasteners such as roofing screws or nails.
The fasteners are driven through the flashing and into the roof’s underlying structure to ensure a secure attachment.
Overlapping
When installing ridge flashings, it is essential to ensure they overlap properly to create a continuous and seamless barrier.
The overlapping sections of the flashings help redirect water away from the ridge and down the roof’s slopes, preventing water penetration.
Valley Flashing
Valley flashings are crucial components in corrugated roofing systems that are designed to effectively manage water runoff in the valleys where two roof slopes intersect.
Their primary function is to guide water away from the joint or valley, preventing water from pooling or leaking into the underlying structure.
Location
Valley flashings are installed in the V-shaped valleys created by the intersection of two roof slopes.
These valleys naturally collect and channel water, making them susceptible to leaks if not properly protected.
Material
Valley flashings are commonly made from metal, such as aluminum or steel, due to their durability and weather resistance.
Metal flashings provide excellent protection against water intrusion and can withstand the elements.
Alternatively, flexible materials like EPDM (Ethylene Propylene Diene Monomer) rubber may also be used, especially in cases where flexibility is required to accommodate the movement of the roof.
Shape and Design
Valley flashings are typically designed to fit the contours of the roof valleys.
They are formed in a V-shape or a similar profile to effectively channel water down the valley and away from the joint.
The shape and design of the flashing ensure that water is directed toward the gutters or other drainage points.
Installation
Valley flashings are installed by positioning them in the valley and aligning them with the roof slopes on either side.
The flashings are securely fastened to the roof decking or underlayment using appropriate fasteners, such as roofing screws or nails.
The fasteners are placed at regular intervals to ensure a secure and tight fit.
Wall Flashing
Wall flashings are essential components in corrugated roofing systems that are installed at the junction where the roof meets a vertical wall or chimney.
Their primary purpose is to create a watertight seal and prevent water from seeping into the building through this vulnerable area.
Location
Wall flashings are installed at the intersection of the roof and a vertical wall or chimney.
This area is prone to water intrusion, as water can easily penetrate the joint between the roof and the vertical surface if not adequately protected.
Material
Wall flashings can be made from various materials, including metal or flexible materials like EPDM (Ethylene Propylene Diene Monomer).
Metal flashings, such as aluminum or steel, are commonly used due to their durability and weather resistance.
Flexible materials like EPDM are also popular choices, especially when the joint between the roof and the wall requires flexibility to accommodate any movement.
Shape and Design
Wall flashings are typically designed to provide a barrier between the roof and the vertical surface.
They are often L-shaped or bent at a 90-degree angle to cover both the roof and the wall.
The shape and design of the flashing ensure that water is directed away from the joint and safely routed down the roof.
Installation
Wall flashings are installed by positioning them against the vertical surface, ensuring a proper fit and alignment with the corrugated roof.
The flashing is then securely fastened to both the roof and the wall using suitable fasteners.
It is important to ensure the flashing is tightly sealed to create a watertight connection.
Drip Edge Flashing
Drip edge flashings are essential components of corrugated roofing systems that are installed along the edges of the roof, specifically at the eaves (lower edge) and rakes (sloping edge).
Their primary function is to guide water away from the roof edges, preventing water from seeping underneath the roofing materials and causing potential damage.
Location
Drip edge flashings are installed horizontally along the edges of the roof, where water runoff occurs.
They are commonly installed at both the eaves, which are the lower edges of the roof, and the rakes, which are the sloping edges of the roof.
Material
Drip edge flashings are typically made of metal, such as aluminum or steel. These materials offer excellent durability, weather resistance, and longevity.
Metal flashings are capable of withstanding harsh weather conditions and are less prone to warping or cracking over time.
Shape and Design
Drip edge flashings are designed with a downward-facing flange or lip. This flange helps to guide water away from the roof edge and directs it into the gutters or onto the ground.
The shape of the flashing is designed to create a barrier that prevents water from infiltrating under the roofing materials.
Installation
Drip edge flashings are installed by positioning them along the edges of the roof, with the downward-facing flange extending over the eaves or rakes.
The flashing is secured to the roof decking or underlayment using appropriate fasteners, such as roofing nails or screws.
Water Diversion
The downward-facing flange of the drip edge flashing acts as a barrier that diverts water away from the roof edge.
It helps to prevent water from flowing back onto the roof surface or being forced underneath the roofing materials.
Instead, the water is directed into the gutters or away from the building’s foundation.
Eave Flashing
Eave flashings are crucial components in corrugated roofing systems that are installed along the lower edge of the roof, specifically at the eaves.
Their primary function is to provide a protective barrier against water intrusion and safeguard the underlying structure from potential damage caused by moisture.
Location
Eave flashings are positioned horizontally along the lower edge of the roof, known as the eaves.
The eaves extend beyond the walls of the building and provide protection for the underlying structure against water runoff.
Material
Eave flashings can be made from various materials, including metal (such as aluminum or steel) or other suitable waterproof materials.
Metal flashings are commonly used due to their durability, resistance to weathering, and ability to withstand harsh conditions.
Alternatively, waterproof materials like EPDM (Ethylene Propylene Diene Monomer), rubber, or PVC (Polyvinyl Chloride) may also be used, providing flexibility and excellent waterproofing properties.
Shape and Design
Eave flashings are designed to create a barrier that prevents water from penetrating the eaves and causing damage to the building’s structure.
They are typically installed along the roof’s edge, overlapping the eaves and extending beyond the roofline.
This design helps direct water away from the eaves and safely route it down the roof.
Installation
Eave flashings are installed during the initial roof installation or as part of a roofing replacement project. They are positioned along the roof’s lower edge, aligning with the eaves.
The flashings are securely attached to the roof decking or underlayment using appropriate fasteners, ensuring a tight and watertight seal.
Water Diversion
The primary purpose of eave flashings is to manage water runoff. They act as a barrier that directs water away from the eaves and prevents it from infiltrating the underlying structure.
By guiding water off the roof and preventing it from pooling or entering the building, eave flashings help maintain the roofing system’s integrity.
Step Flashing
Step flashings are vital components of corrugated roofing systems, specifically used around roof penetrations such as chimneys, skylights, or dormers.
Their primary purpose is to provide a watertight barrier and redirect water away from these vulnerable areas, ensuring effective waterproofing and preventing leaks.
Location
Step flashings are installed in a “stepped” pattern along the sides of roof penetrations where they intersect with the roof surface.
They are positioned in a series of overlapping layers to create a continuous barrier that diverts water away from the penetration points.
Material
Step flashings are commonly made of metal due to their durability and resistance to weathering.
Aluminum, galvanized steel, or copper are frequently used because they offer excellent strength and corrosion resistance.
The choice of material depends on factors such as the roofing system, climate, and aesthetic preferences.
Shape and Design
Step flashings are designed to integrate seamlessly with the roof and the roof penetration. Each step flashing piece is installed at a slight angle, overlapping the adjacent piece above it.
This design allows water to flow down and away from the penetration point, preventing water infiltration and potential leaks.
Installation
Step flashings are typically installed during the construction or installation of roof penetration.
Each piece of step flashing is secured directly to the roof deck or underlayment using appropriate fasteners like roofing nails or screws.
The flashing is aligned with the sides of the penetration, ensuring a snug fit and proper water diversion.
Water Diversion
The stepped pattern of the flashings creates a series of overlapping layers that effectively redirects water away from the penetration points. This helps prevent water from seeping into the roof system or the structure beneath.
Properly installed step flashings ensure that water is safely directed off the roof, minimizing the risk of leaks and water damage.
Maintenance Tips for Corrugated Roof Flashing
Proper maintenance of corrugated roof flashing is essential for the longevity and performance of your roofing system.
By regularly inspecting and maintaining the flashing, you can prevent potential leaks and water damage.
- Perform a visual inspection of the flashing at least once a year. Look for signs of damage, such as cracks, rust, or loose fasteners. Pay particular attention to areas where the flashing meets other roofing components, such as walls, chimneys, or skylights.
- Remove any debris, leaves, or branches that may have accumulated on or around the flashing. Debris can trap moisture and accelerate the corrosion process. Use a soft brush or broom to gently sweep away debris, being careful not to damage the flashing.
- Ensure that the flashing is properly aligned and securely attached to the roof. Check for any signs of shifting or misalignment, which can compromise the effectiveness of the flashing.
- If you identify any damaged flashing during your inspection, it’s crucial to address it promptly. Small cracks or gaps can be repaired with appropriate roofing sealant or adhesive. For more significant damage or deterioration, consider replacing the damaged sections of flashing to maintain a watertight seal.
- Inspect the sealant or roofing adhesive applied to the flashing. Look for signs of wear, cracking, or separation. If the sealant appears damaged or compromised, remove the old sealant and reapply a fresh layer to ensure a proper and watertight seal.
- Keep gutters and downspouts clean and free from debris to prevent water overflow. Clogged gutters can cause water to back up onto the roof, potentially compromising the flashing’s integrity. Regularly clean gutters and downspouts and ensure they properly direct water away from the roof.
- If you notice any signs of water leakage or staining on ceilings or walls inside your home, it could indicate a problem with the flashing. Act promptly to identify and repair the source of the leak.
Bottom Line
With this comprehensive guide, you now have the knowledge and step-by-step instructions to install flashing on your corrugated roof confidently.
Remember, the correct flashing installation is crucial for the long-term protection of your roof and home.
By following these guidelines and paying attention to maintenance, you’ll enjoy a durable and resilient corrugated roof that withstands the elements for years to come.
So, get started and give your roof the protection it deserves with expertly installed flashing.
FAQ
Can I screw in flashing on roof?
While modern flashing is typically installed using adhesive, older homes may have traditional flashing that was also secured with screws or nails.
For example, step-flashing around chimneys is often made of metal and nailed down before being covered by shingles.
The specific method of installation may vary depending on the type of flashing and the roofing system.
What screws to use for flashing roof?
When selecting screws for flashing a roof, it is crucial to prioritize durability and resistance to corrosion.
Stainless steel screws are highly recommended, particularly when working with aluminum metal roofs, as they offer excellent corrosion resistance.
For added protection, consider using mechanically galvanized fasteners with a zinc coating to guard against rust.
Alternatively, opt for zinc aluminum cap screws or stainless steel screws instead of carbon steel screws, as they provide better resistance to corrosion in outdoor environments.
Do all roofs need flashing?
Yes, all roofs typically require flashing. Roof flashing is an essential component of a roofing system as it helps to redirect water away from vulnerable areas such as walls, chimneys, and roof valleys.
