Porch Roof Flashing Installation: How to Do it the Right Way


If you plan to add a new porch to your home, you’ve perhaps thought about roof flashing installation. Most homeowners with porches attached to their houses tend to have water leak issues at the points where the porch roof meets the wall of the house.

Roof flashing installation should help to prevent leaks by sealing the junctions between the porch roofs and the adjacent walls. When installed incorrectly, the flashing may still allow water to leak into the house. So how can you install porch roof flashing properly?

This guide explores the basics of roof flashing installation, including what it entails and the right steps to follow to avoid future inconveniences. Keep reading to learn more.

What is Porch Roof Flashing Installation?

Roof flashing installation involves adding a flashing material on the gaps between the roof of a porch addition and the sidewall of a house. You’ll install step flashing along with the porch’s roof shingles. That will ensure that water flows away from the wall.

Before installing roof flashing, you have to remove the siding on the wall portion that meets the porch addition. If the process seems complicated, hire a reliable roofing company like Roof Master & Construction to help you. Learn more about the company at the link. 

Installing the roof flashing is not an easy task. The good news is that you can properly install the roof flashing yourself when you follow the correct procedure.

How to Install Roof Flashing on the Porch Roof: Step-by-Step Guide

If your porch roof is leaking due to poor flashing installation, you can stop the leaks by reinstalling the roof flashing correctly. Here are the steps to follow during installation.

Step 1: Prepare the Installation Area

You have to prepare the area where you intend to install the new porch roof flashing. If the existing flashing is faulty, you must first remove it to create space for new flashing.

If there is a siding on the wall adjacent to the porch roof, consider removing the lowest strip to install the new flashing below it. Remember to put on leather-palm gloves when doing that to avoid potential injuries.

Step 2: Take the Porch-Roof Joint Measurements

Using a measuring tape, measure the length of the joint between the porch roof and the house wall. It will help you figure out the number of flashings you’ll need on the rooftop.

Generally, most flashings come in sections, each measuring 10-feet long. If your porch-roof joint is longer, you’ll have to join two pieces together to fit the entire length.

Step 3: Choose the Right Flashing Material

There are several flashing materials on the market, including copper, galvanized metal, and aluminum. However, most DIY homeowners prefer aluminum as it is easy to install.

In a nutshell, let’s look at the features of the various roofing materials.

  • Aluminum: Aluminum is soft and easy to manipulate, making it a famous roof flashing material. However, it may need to be coated when being used in alkaline environments to prevent corrosion.
  • Pre-Bent Steel: Steel is another excellent material for roof flashing because of its numerous benefits. It is malleable and corrosion-resistant when galvanized. Its aesthetic value is another reason many homeowners love it.
  • Copper Metal: Copper is the premium choice for flashing installation projects. It is malleable and soldiers easily. Copper can also discolor over time when it patinas, which may be beneficial for some homeowners.

Before selecting any of the roof flashing materials, check if the local building codes allow you to install the material of your choice. Some building codes may specify the materials for flashing in their regions and the minimum thickness required.

Step 4: Cut the Flashing Material to Size

If the flashing is longer than the length of the porch-roof joint, cut it to size using tin snips. Cut one side of the flashing piece at an angle from the end corner to the bend, depending on the roof’s pitch. 

The purpose of the angle cut is to allow one part of the flashing to rest flat on the roof while the curt part wraps around the house corner. It’s a freehand cut, and you may try severally before the flashing piece rests on the roof correctly.

The bend on the flashing will fit automatically into the joint where the porch roof meets with the wall of the house.

Step 5: Install the Cut Flashing Piece

At the corner, place the flashing piece down over the shingle that’s already in place with the corner cut facing upwards. Hammer the angled cut around the corner of the roof-porch seam until it rests flat. Secure the piece to the wall using a roofing nail.

Apply caulking on the edges of the flashing piece where it meets the roof and the wall of the house on the corner. If you handle this area poorly, the chances are that it will leak because the flashing won’t cover the entire area. The caulk helps to prevent leaks.

Step 6: Install Another Flashing Piece up the Seam 

Lay another piece of flashing up the seam while ensuring that it overlaps the corner piece. If it has an overhang on the upper corner on the lower end, hammer it to bend it around the corner flat. Nail the flat end on the wall with a nail at each corner.

Step 7: Lay Down the Shingles

Once you’ve installed the flashing pieces, install a row of shingles covering the roof and a piece of seam flashing. The first shingle’s end should extend over the flashing and onto the flat section of the corner flashing piece.

Install the next flashing piece, ensuring that the bend lies in the seam between the roof and the house. The bottom edge of the piece should end immediately below the nail line of the shingles you just laid. Nail the upper part to the wall in the upper corner.

Continue up the roof in that manner as you alternate the flashings with rows of shingles. Make sure that the nails are not visible, except the last one hammered.

Final Words 

When planning a porch roof flashing installation, you should do it properly to maintain the structural integrity of your roof. That way, you can avoid the leaks that usually occur in the joints between the porch roof and the wall. The good news is that you now know the steps on how to install roof flashing by yourself.