How To Install a Rain Diverter

A rain diverter is a practical device that redirects rainwater away from your home’s entry points to ensure dry and safe entryways. It also helps prevent potential ice buildup, reducing the risk of slip hazards. In the video above, This Old House general contractor Tom Silva demonstrates how to install a rain diverter. We’ll also offer tips on maintaining it and other ways to manage rainwater in this guide. 

What Is a Rain Diverter?

A rain diverter is a simple piece of flashing you can install on your roof to redirect water flow. It’s often made from the same material as drip edge flashing, commonly used along roof edges. When you install a diverter at an angle under your roof shingles, it creates a channel that diverts water away from vulnerable areas, such as doorways or walkways.

Installing a rain diverter offers several advantages, such as the following:

• Extends the life of exterior paint and finishes
• Improves safety by reducing slip hazards
• Prevents water from dripping onto entryways
• Protects doors and windows from water damage
• Reduces the risk of ice formation on steps and walkways

Materials and Tools Needed for a Rain Diverter

Gather the following materials and tools for your installation:

• 80-grit sandpaper
• Aviation snips
• Caulk gun
• Drip edge flashing
• Flat pry bar
• Hammer
• Ladder
• Roofing nails
• Safety equipment (gloves, safety glasses)
• Spray paint (to match roof color)
• Tripolymer caulk

Tools

Prepare the Flashing for Your Rain Diverter

Before you install your rain diverter, prepare the flashing as follows. This will guarantee a successful installation and seamless integration with your roof’s appearance.

Cut and Paint the Flashing

1. Measure the length needed for your diverter.
2. Use aviation snips to cut the flashing to the appropriate size.
3. If necessary, cut the flashing in half to create two pieces for a longer diverter.
4. Sand the underside of the flashing with 80-grit sandpaper to help the paint adhere.
5. Wipe the sanded surface clean to remove any debris.
6. Apply spray paint that matches your roof color to the bottom surface and upturned edge of the flashing.
7. Allow the paint to dry completely before installation.

Rain Diverter Installation Process

Installing a rain diverter requires careful attention to detail to ensure proper function and prevent leaks. Follow these steps to install your rain diverter:

Step 1: Prepare the Roof

Use a flat pry bar to carefully loosen the shingles where you want to install your diverter. Be gentle to avoid damaging the shingles or creating weak spots on your roof.

Step 2: Position the Flashing

1. Lay one piece of flashing upside down (with the painted side facing up) on the roof at an angle.
2. Slip the flashing under the loosened shingles.
3. If using two pieces, overlap them slightly for better water flow and sealing.

Step 3: Secure the Diverter

1. Use roofing nails to secure the flashing.
2. Place each nail under a shingle to maintain the roof’s waterproof integrity.
3. Space the nails evenly along the length of the flashing for proper support.

Step 4: Seal and Finish

1. Apply tripolymer caulk over each nailhead to prevent water penetration.
2. Use additional caulk to seal down the edges of the shingles covering the diverter.
3. Smooth the caulk to ensure a watertight seal and neat appearance.

Step 5: Test the Rain Diverter

After installation, we recommend testing the rain diverter as follows to verify that it’s working properly:

1. Use a garden hose to simulate rainfall on the roof above the diverter.
2. Observe how the water flows along the diverter.
3. Check that your diverter is redirecting water away from the intended area.
4. Look for any signs of leaks or improper water flow.
5. If you notice any issues during testing, adjust the diverter’s position or sealing.

Rain Diverter Maintenance Tips

Once installed, you’ll need to maintain your rain diverter to keep it functioning properly. Follow these best practices:

• Check the caulk seals annually and reapply if necessary.
• Clear any debris that may accumulate on or around the diverter.
• Regularly inspect the diverter for damage or loose sections.
• Repaint the diverter as needed to maintain its appearance and protect against rust.

Additional Water Management Solutions

A well-maintained gutter system coupled with rain diverters can create a robust defense against water intrusion. However, you can also apply other complementary water management techniques if you need more protection. These options may be a good idea if your yard frequently gets waterlogged or has standing water after heavy rain, or if there are other areas of your home where water often pools. You should also consider them if you’re in an area prone to flooding or have a lot of slopes on your property.

• French drains: French drains can direct water away from difficult areas using a perforated pipe system.
• Proper grading: Proper grading ensures your yard slopes away from your house, preventing water from pooling near the foundation.
• Rain chains: These chains guide water from the roof to the ground or a drainage system, which minimizes soil erosion and protects your landscape.