What is Step flashing and How to Install It - Digital Roofing Innovations

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What is Step flashing and How to Install It

What is Step flashing and How to Install It

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One of the most overlooked areas of your home is where your roof deck meets a side wall.

When the rain starts to pour, absent flashing in these areas put your roof in severe danger.

Combined with wind-driven rain, the water can easily seep underneath your shingles and damage your roofing structure.

How do you fix this problem? What steps should you take for the safety of your home?

The solution is step flashing. In this guide, we’ll teach you how to install one, but first…

What is Step Flashing?

Step flashing is a type of flashing that is applied to areas where your roof meets a side wall. The material used for step flashing is either aluminum, galvanized steel, or copper.

Preferably, galvanized steel is a better option than aluminum. As for copper, it will last 100 years or more, but it is very expensive.

If you’re wondering what is flashing on a roof, here’s what we can tell you:

Put simply, it’s a piece of metal bent at a 90-degree angle and applied to vulnerable areas of your roof. This bent piece of metal is installed in the joint between your roof shingles and the adjacent wall.

There are also other techniques, such as continuous, base, and valley flashing.

Each type has its own specific functionality and area of application. For example, we already know step flashing is ideal for areas where your roof meets a sidewall.

On the other hand, base flashing is used for your chimneys, while valley flashing is for your roof valleys. Continuous flashing works similarly to step flash, wherein it protects the joints between a sloped roof and a vertical wall.

Benefits of Step Flashing

The main benefit of step flashing is providing structural integrity to your roof. Since water leaks easily seep in the sidewall and are one of the most vulnerable areas, step flashing prevents this from happening.

As a result, it’s advised that you shouldn’t skip on flashing installations just to cut down costs. Without it, water leaks damage your roof structure and also result in mold & mildew growth.

How to Install Step Flashing

Before we dive into how to install step flashing, here are two key reminders to take note of before you start:

  1. The primary concern of a step flashing installation is to counter any water that flows downhill. This is not always the case, though. It’s also possible for water to run uphill like when it absorbs debris or backs up behind the ice. As a result, you should lap all flashing by 2 inches, at least.
  2. Don’t nail step flashing to your roof and wall. You’ll want to avoid placing extra holes on your roof’s surface. Instead, you should only nail it to the sidewall. The next flashing piece and siding will then cover the nail head.

Step 1: Start with Corner Flashing

When installing step flashing on roof, corner flashing should always come first.

  1. Once you’ve installed corner flashing to the sidewall, cut the step flashing piece at a 45-degree angle, starting from the outside corner to the bent seam.
  2. Bend the trimmed piece down and back so it can sit flat in the corner.
  3. Hammer in two nails in the wall near the top. Make sure there is one nail for each face.

Step 2: Apply Sealant

Apply roofing sealant to wherever the next flashing piece will overlap. This will help seal the corner. Make sure to apply the bead of sealant evenly since it’s essential for the next step.

Step 3: Bend Your Flashing Piece Along the Plumb Line

  1. Take your first flashing piece and bend it so that it makes a clean overlap over the corner flashing you installed in Step 1.
  2. Hammer in one nail to the step flashing piece to hold it in place.

Step 4: Install the Next Piece in a Weave Fashion

The next pieces should follow a weave fashion. It’s essential to properly seal your sidewall. Each step flashing piece should overlap the shingle below it and under the shingle above.

Note: As a guide, remember that the bottom edge of the flashing piece should extend below the nail line. 

Step 5: Cut Along the Fold Line

After installing all the pieces, you’ll eventually reach the roof peak. Since the roof peak is two slopes that meet, you’ll have to do this step for both sides.

  1. Once you reach the roof peak, on the first side, you’ll want to cut the flashing piece along the fold line and bend the lower flap down. Hammer in one nail to keep it in place.
  2. Do the same for the other side, installing the pieces in a weave fashion together with the shingles.
  3. Before you put the final piece, vertically apply a bead of sealant in the piece you installed on the first side.
  4. The final piece should also be cut along the fold line, and its flap should also be bent down. Afterward, press the final piece onto the piece on the first side.
  5. Finally, hammer in one nail into the wall to secure the final piece.

Retrofitting Step Flashing: Re-Roofing vs. Tearing Off the Shingles

Installing flash on roofs is a step you should take on first before proceeding to any shingle installment.

In some cases, the installation needs re-working or lacks an element that is vital to the roof structure.

Retrofitting is a case that happens when your roofing contractor leaves the old flashing as is and had no step flashing installed.

In times like these, you can retrofit flashing by either re-roofing or tear off the shingle.

Some prefer to roof over existing shingles, and while re-roofing is permissible, there are also risks involved.

What makes it appealing is it’s less costly, and the installation is fast and easy.

Compared to tearing off your roof shingles, this will require more time, labor, and effort overall. Take note though, that tearing off your shingles provides you with twice the advantages and benefits compared to re-roofing.

These advantages are:

  • Proper Shingle Installation and Sealing
  • Proper flashing in roof
  • Proper adhering to your roof deck
  • Manufacturer Warranty

With re-roofing, manufacturer warranties don’t apply, and this will also prevent your roofing contractor from inspecting your roof deck for any damage or rotting.

In addition, it’s possible your roofing contractor will not use longer roofing nails that allow it to penetrate deep enough into the wood deck.

Finally, re-roofing isn’t exactly on the list of best practices out there.

Regarding retrofitting step flashing, most contractors refrain from accepting jobs like this because it’s added labor and cost on their part. It’s also more of a hassle and can lead to even bigger problems in the future.

If you meet a case like this in the future, it’s better to opt for tearing off your shingle piece by piece for a more effective installation.

When to Call a Professional

Flashing a roof is no simple task and requires roofing experience as well.

In addition, this step is so vital to your roofing structure that poor installations can easily lead to repeating the installation process all over again, which doubles your costs.

If you have plans of installing step flashing on your own, we recommend calling a professional first to assess any roof leaks and which areas need the highest priority and urgency.

Installing flashing on roofs does take skill, and it can also be tricky to install. If there are any gaps (even one is enough), water will leak through and damage your roofing structure.

Improper roof flashing installations can also lead to potential danger for your roof during winter.

When the snow on your roof melts and then freezes over again, this cycle of melting and freezing will cause the ice to back up between the gaps & cracks of the flashing and penetrate your home.

Bottom Line

Step flashing is best left to professionals who have handled similar jobs in the past or are familiar with installing one.

Roofs with different pitches and slopes are also essential factors to consider in the installation process. After all, not all roofs are constructed the same.

Some have vents, pipes, skylights, and chimneys, which makes the installation more challenging than a flat roof.

All in all, your roofing contractors should be able to meet your needs and install step flashing appropriately while protecting your roof’s structural integrity.

Last but not least, check the building code in your area. If there are any standards or requirements needed, you’ll have to follow these guidelines accordingly, too.

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