Installing roof flashing against a wall is a crucial step in preventing water damage to your home. When done correctly, flashing channels water away from the roof deck and down the wall, protecting it from rot and leaks. This guide will walk you through the process of installing roof flashing against a wall, ensuring your home stays dry during even the heaviest downpours.
Before you begin, gather your materials, including step flashing, roofing cement, and a hammer or nail gun. Step flashing is specifically designed to create a watertight seal between the roof and wall. It is typically made of aluminum or galvanized steel and comes in various widths and lengths. Roofing cement is a sticky substance that helps seal the flashing against the roof and wall, preventing leaks. Ensure you have enough materials to cover the entire area where the roof meets the wall.
The first step is to prepare the surface where the flashing will be installed. This involves cleaning the roof and wall of any dirt or debris. If necessary, scrape away any old caulk or sealant that may interfere with the flashing’s adhesion. Once the surfaces are clean, you can start installing the step flashing. Cut the flashing to the desired length and bend it at a 90-degree angle. The longer leg of the flashing should extend up the wall, and the shorter leg should extend over the roof shingles. Secure the flashing to the wall using roofing nails or a nail gun. Drive the nails into the wall at a slight downward angle to prevent water from seeping underneath the flashing.
Selecting the Right Flashing Material
Choosing the appropriate flashing material is crucial for ensuring effective sealing and protection of roof-to-wall intersections. Here are key considerations when selecting the right material:
Metal Flashing
- Durability: Metal flashing is highly resistant to corrosion, weathering, and impact, making it ideal for long-lasting performance.
- Flexibility: Aluminum and copper flashing are particularly flexible, allowing them to conform to complex shapes and create tight seals.
- Fire Resistance: Metal flashing is non-combustible, providing an additional layer of fire resistance to the roof structure.
Asphalt Flashing
- Cost-Effective: Asphalt flashing is an economical option that offers adequate protection against water infiltration.
- Self-Adhesive: Asphalt flashing is typically self-adhesive, simplifying installation by eliminating the need for additional sealants.
- Temperature Sensitivity: Asphalt flashing can become brittle in cold weather or melt in excessive heat, compromising its effectiveness.
Rubber Flashing
- Elasticity: Rubber flashing is highly elastic, allowing it to expand and contract with temperature changes, maintaining a tight seal.
- UV Resistance: Rubber flashing is resistant to ultraviolet radiation, preventing degradation and ensuring longevity.
- Limited Color Options: Rubber flashing typically comes in limited colors, which may not be suitable for all aesthetic requirements.
| Material | Durability | Flexibility | Cost |
|---|---|---|---|
| Metal | Excellent | Good (Aluminum, Copper) | Moderate to High |
| Asphalt | Good | Fair | Low |
| Rubber | Very Good | Excellent | Moderate |
Preparing the Wall Surface
Before installing roof flashing against a wall, it is essential to prepare the wall surface to ensure a proper seal and prevent water damage. This involves several steps:
Cleaning the Wall
- Remove any dirt, debris, or mold from the wall using a stiff brush or power washer.
- Allow the wall to dry completely before proceeding.
Inspecting the Wall for Cracks and Holes
- Carefully inspect the wall for any cracks, holes, or damage that may compromise the seal.
- If any damage is found, repair it with appropriate materials such as caulk or mortar.
Smoothing the Wall Surface
- For a smooth and even surface, sand or grind down any rough patches or protrusions on the wall.
- This will create a better surface for the flashing to adhere to and prevent leakage.
Installing a Backer Rod
- Install a backer rod made of foam or polyethylene into the joint between the wall and roof flashing.
- The backer rod provides support for the flashing and helps prevent water from seeping behind it.
Priming the Wall
- Apply a primer to the wall surface to enhance the adhesion of the flashing.
- Use a primer specifically designed for the type of wall material (e.g., masonry, stucco, vinyl).
- Allow the primer to dry completely before installing the flashing.
Applying Base Flashing
Installing base flashing is the first step in waterproofing the junction between the wall and roof. It helps to prevent water from leaking into the building envelope, which can lead to costly damage. Here’s a step-by-step guide on how to apply base flashing:
- Cut the base flashing to size. Measure the length of the wall where flashing will be installed and cut the flashing to that length. The flashing should extend at least 6 inches up the wall and 6 inches out over the roof.
- Bend the flashing into a 90-degree angle. Mark the center of the flashing and bend it into a 90-degree angle, forming a “L” shape. The vertical leg of the flashing will be attached to the wall, and the horizontal leg will be attached to the roof.
- Apply adhesive to the base of the vertical leg. Apply a generous amount of roofing adhesive to the base of the vertical leg of the flashing. Press the flashing firmly against the wall, starting at the bottom and working your way up.
- Secure the base flashing with nails. Drive roofing nails through the horizontal leg of the flashing into the roof sheathing. Space the nails 6 inches apart. Make sure to drive the nails in straight and flush with the top of the flashing.
- Seal the edges of the flashing. Apply a bead of roofing sealant around the edges of the flashing, where it meets the wall and the roof. This will help to further waterproof the joint.
Additional Tips
- Use galvanized steel or aluminum flashing, which are highly resistant to corrosion.
- Make sure the flashing extends at least 6 inches up the wall and out over the roof. This will help to prevent water from leaking behind the flashing.
- Apply a generous amount of roofing adhesive to the base of the flashing. This will help to keep the flashing in place and prevent water from leaking through.
Installing Step Flashing
Step flashing is a type of flashing that is installed between the roof and a wall. It is used to prevent water from leaking into the home at the intersection of the two surfaces. Step flashing is typically made of metal, such as aluminum or copper. It is cut into strips that are wide enough to extend over the roof and down the wall by at least 4 inches. The strips are then bent at a 90-degree angle to create a “step” that the roof shingles can overlap.
To install step flashing, you will need the following materials:
- Step flashing
- Tin snips
- Hammer
- Nails
- Caulk gun
- Caulk
Follow these steps to install step flashing:
- Measure and cut the step flashing to the desired length. The strips should be wide enough to extend over the roof and down the wall by at least 4 inches.
- Bend the strips at a 90-degree angle to create a “step” that the roof shingles can overlap.
- Install the step flashing over the roof underlayment and under the roof shingles. The step should face up and the flashing should extend down the wall by at least 4 inches.
- Nail the step flashing in place. Use roofing nails and space them about 6 inches apart. **Start nailing the flashing about 3 inches up the wall to prevent water from getting underneath the flashing**
- Caulk the joint between the step flashing and the wall. This will help to seal out water and prevent leaks.
Tips for Installing Step Flashing
- Use a chalk line to mark the location of the step flashing before you cut and install it.
- Make sure that the step flashing is installed under the roof shingles and over the roof underlayment.
- Nail the step flashing in place securely. Space the nails about 6 inches apart.
- Caulk the joint between the step flashing and the wall to seal out water.
Sealing the Flashing
Sealing the flashing is crucial to prevent water penetration and leaks. Follow these steps for a secure seal:
1. Remove Loose Rust and Debris
Clean the flashing and wall surface thoroughly using a wire brush or sander. Remove any loose paint, rust, or debris that could compromise the seal.
2. Apply Roofing Cement
Apply a thick bead of roofing cement along the top and bottom edges of the flashing where it meets the wall. Use a putty knife or caulk gun to ensure even application.
3. Embed Reinforcement Fabric
Cut strips of reinforcement fabric (e.g., fiberglass mesh or tar paper) slightly wider than the flashing. Place the fabric over the roofing cement and press it down firmly into the adhesive.
4. Seal with Additional Roofing Cement
Apply another layer of roofing cement over the reinforcement fabric, ensuring it covers the edges and creates a watertight seal. Smooth out the cement using a putty knife or trowel.
5. Finishing Touches
To enhance the seal and provide a finished look:
| Additional Sealing Options | |
| Option | Description |
| Caulk | Apply a bead of silicone or polyurethane caulk along the edges of the flashing for added water resistance. |
| Counterflashing | Install a second layer of flashing (counterflashing) over the step flashing at the top of the wall to create a double layer of protection. |
| Metal Capping | Cover the exposed edges of the flashing with a strip of metal capping to improve durability and aesthetics. |
Counter Flashing Installation
Once the step flashing is in place, the next step is to install the counter flashing. Counter flashing is a metal strip that is installed on top of the step flashing and extends up the wall. It helps to prevent water from leaking behind the step flashing and into the wall.
Materials Needed
- Counter flashing
- Roofing cement
- Nails
- Hammer
- Utility knife
Instructions
- Measure and cut the counter flashing. The counter flashing should be the same length as the step flashing below it. Use a utility knife to cut the counter flashing to size.
- Apply a bead of roofing cement to the top of the step flashing. This will help to seal the joint between the step flashing and the counter flashing.
- Place the counter flashing on top of the step flashing. Align the counter flashing with the edge of the roof and press it down into the roofing cement.
- Nail the counter flashing to the wall. Use nails to secure the counter flashing to the wall. Space the nails about 6 inches apart.
- Caulk the joint between the counter flashing and the wall. This will help to further seal the joint and prevent water from leaking.
- **Additional Notes:
- The counter flashing should extend up the wall at least 4 inches.
- If the counter flashing is not long enough to reach the top of the wall, you can overlap two pieces of counter flashing.
- Be sure to use a sealant that is compatible with the type of roofing material you are using.
Valley Flashing Placement
Valley flashing is used to prevent water from leaking into your home at the intersection of two roof planes. It is important to install valley flashing correctly to ensure that it is effective. Here are the steps on how to install valley flashing against a wall:
1. Cut the valley flashing to the correct length. The flashing should extend at least 6 inches beyond the edge of the wall on both sides.
2. Fold the flashing up around the edges of the wall. The flashing should be folded up at a 90-degree angle to create a lip.
3. Nail the flashing to the wall. Use roofing nails to secure the flashing to the wall. The nails should be spaced about 6 inches apart.
4. Install the roofing felt over the flashing. The roofing felt will help to seal the flashing and prevent water from leaking into your home.
5. Install the roofing shingles over the roofing felt. The roofing shingles will help to protect the flashing and the roofing felt from the elements.
6. Install the chimney flashing. The chimney flashing will help to prevent water from leaking into your home around the chimney.
7. Install the ridge cap. The ridge cap will help to protect the peak of your roof and prevent water from leaking into your home. The ridge cap should be installed over the ridge of the roof and secured with roofing nails.
Here is a table summarizing the steps on how to install valley flashing against a wall:
| Step | Description |
|---|---|
| 1 | Cut the valley flashing to the correct length. |
| 2 | Fold the flashing up around the edges of the wall. |
| 3 | Nail the flashing to the wall. |
| 4 | Install the roofing felt over the flashing. |
| 5 | Install the roofing shingles over the roofing felt. |
| 6 | Install the chimney flashing. |
| 7 | Install the ridge cap. |
Chimney Flashing Techniques
Chimney flashing is a critical component of any roof, as it helps prevent water from seeping into the home. There are several different techniques that can be used to flash a chimney, each with its own advantages and disadvantages.
Step-by-Step Guide to Installing Roof Flashing Against a Wall:
1. Install the base flashing: This is a strip of metal that is installed around the base of the chimney. It should be sealed with sealant to prevent water from leaking.
2. Install the counter flashing: This is a strip of metal that is installed over the base flashing and up the side of the chimney. It should be sealed with sealant and nailed into place.
3. Install the step flashing: This is a series of small pieces of metal that are installed over the counter flashing and up the side of the chimney. They should be overlapped and sealed with sealant to prevent water from leaking.
4. Install the cap flashing: This is a piece of metal that is installed over the top of the chimney. It should be sealed with sealant and nailed into place.
5. Install the side flashing: This is a strip of metal that is installed down the side of the chimney. It should be sealed with sealant and nailed into place.
6. Install the chimney cricket: This is a piece of metal that is installed over the top of the chimney and down the side of the roof. It helps to divert water away from the chimney.
7. Seal all seams and joints: All seams and joints in the flashing should be sealed with sealant to prevent water from leaking.
8. Inspect the flashing regularly: The flashing should be inspected regularly for any damage or wear. Any damage should be repaired as soon as possible to prevent water from leaking into the home.
| Chimney Flashing Technique | Advantages | Disadvantages |
|---|---|---|
| Step flashing | Easy to install | Can be time-consuming |
| Counter flashing | More durable than step flashing | More difficult to install |
| Cap flashing | Provides the best protection against water | Most expensive option |
Vent Pipe Flashing Considerations
When installing roof flashing against a wall, it is important to consider the following factors for vent pipe flashing:
9. Vent Pipe Height and Proximity to Wall
The height of the vent pipe and its proximity to the wall can impact the type of flashing required. If the pipe is tall and close to the wall, a flashing base may be necessary to create a watertight seal. Depending on the height and proximity of the pipe, additional flashing material may also be required to ensure proper drainage around the pipe to prevent water from seeping into the wall or roof. In cases where the vent pipe is particularly tall or is in a high-wind area, additional reinforcement may be needed to secure the flashing and prevent damage.
The table below provides a guide to the recommended flashing materials and techniques based on the height and proximity of the vent pipe to the wall:
| Vent Pipe Height and Proximity to Wall | Recommended Flashing Materials and Techniques |
|---|---|
| Vent pipe less than 12″ tall and more than 6″ from the wall | No flashing base required. Install flashing directly to the roof using counter flashing and sealants. |
| Vent pipe less than 12″ tall and less than 6″ from the wall | Install flashing base to create a watertight seal at the base of the pipe. Install flashing around the pipe and secure with counter flashing and sealants. |
| Vent pipe more than 12″ tall and less than 6″ from the wall | Install flashing base to create a watertight seal at the base of the pipe. Install flashing around the pipe and tuck it behind the base flashing. Secure with counter flashing and sealants. |
| Vent pipe more than 12″ tall and more than 6″ from the wall | Install flashing base with a step flange to accommodate the height of the pipe. Install flashing around the pipe and tuck it behind the flange. Secure with counter flashing and sealants. |
Finishing Touches
After the flashing is installed, there are a few finishing touches that you should take care of. First, you should inspect the flashing for any gaps or holes. If you find any, you should seal them with a waterproof sealant.
Next, you should paint the flashing to match the color of your roof. This will help to blend the flashing in and make it less noticeable.
Finally, you should clean up any debris that has accumulated during the installation process.
Maintenance
To ensure that the flashing continues to function properly, you should inspect it regularly and perform maintenance as needed. Here are a few tips for maintaining your roof flashing:
- Inspect the flashing for any gaps or holes. If you find any, you should seal them with a waterproof sealant.
- Clean the flashing to remove any debris that has accumulated.
- Repaint the flashing as needed to protect it from the elements.
10. Additional Maintenance Tips for Roof Flashing
In addition to the tips above, here are a few more things you can do to help maintain your roof flashing:
| Tip | Description |
|---|---|
| Inspect your flashing after every major storm. | This will help you to identify any damage that needs to be repaired. |
| Clean your flashing regularly with a mild detergent and water. | This will help to remove any dirt and debris that could cause the flashing to corrode. |
| Lubricate the moving parts of your flashing with a silicone-based lubricant. | This will help to keep the flashing functioning smoothly. |
How To Install Roof Flashing Against A Wall
Roof flashing is an important part of any roofing system. It helps to prevent water from leaking into the home and can also help to improve the appearance of the roof. Roof flashing is typically made of metal and is installed around the perimeter of the roof, as well as around any chimneys or other protrusions. There are a few different types of roof flashing, but the most common type is step flashing.
Step flashing is installed in a series of overlapping pieces, with each piece being slightly higher than the previous one. This creates a watertight seal that prevents water from leaking into the home. Step flashing is typically used on roofs with a slope of 3:12 or greater.
To install roof flashing against a wall, you will need the following materials:
- Step flashing
- Roofing nails
- Caulk gun
- Caulk
- Hammer
Once you have gathered your materials, you can begin the installation process. Start by cutting the step flashing to the desired length. The flashing should be long enough to extend at least 6 inches up the wall and 6 inches over the roof shingles. Once the flashing is cut, you can begin to install it.
To install the flashing, start by nailing the bottom edge of the flashing to the wall.
Once the bottom edge is nailed in place, you can begin to bend the flashing up the wall. As you bend the flashing, be sure to overlap the previous piece by at least 2 inches. Continue bending the flashing up the wall until you reach the top. Once the flashing is in place, you can nail it to the wall.
Once the flashing is nailed in place, you can apply a bead of caulk to the seam between the flashing and the wall. This will help to seal the seam and prevent water from leaking into the home.
People Also Ask About How To Install Roof Flashing Against A Wall
What is the best type of roof flashing for a wall?
The best type of roof flashing for a wall is step flashing. Step flashing is a type of flashing that is installed in a series of overlapping pieces, with each piece being slightly higher than the previous one. This creates a watertight seal that prevents water from leaking into the home.
How do I install roof flashing around a chimney?
To install roof flashing around a chimney, you will need to cut the flashing to the desired length. The flashing should be long enough to extend at least 6 inches up the chimney and 6 inches over the roof shingles. Once the flashing is cut, you can begin to install it.
Start by nailing the bottom edge of the flashing to the chimney. Once the bottom edge is nailed in place, you can begin to bend the flashing up the chimney. As you bend the flashing, be sure to overlap the previous piece by at least 2 inches. Continue bending the flashing up the chimney until you reach the top. Once the flashing is in place, you can nail it to the chimney.
How do I repair roof flashing?
To repair roof flashing, you will need to remove the damaged flashing and replace it with new flashing. Start by removing the nails that are holding the damaged flashing in place. Once the nails are removed, you can carefully remove the flashing.
Once the damaged flashing is removed, you can install the new flashing. Start by nailing the bottom edge of the new flashing in place. Once the bottom edge is nailed in place, you can begin to bend the flashing up the wall or chimney. As you bend the flashing, be sure to overlap the previous piece by at least 2 inches. Continue bending the flashing until you reach the top. Once the flashing is in place, you can nail it in place.
