As a seasoned professional in the field of construction and home maintenance, I've had the opportunity to work on a variety of projects involving flashings, including chimney flashing. Chimney flashing is a critical component of a roof's weatherproofing system. It's the piece that bridges the gap between the roof and the chimney, preventing water from seeping in and causing damage. Here's a detailed step-by-step guide on how to flash a chimney:

### Step 1: Assess the Situation
Before you start, it's important to assess the current state of the chimney and the roof. Look for signs of damage or wear that could affect the flashing installation. This includes checking for rust, rot, or any gaps where water might infiltrate.

### Step 2: Remove Old Flashing
If there's existing flashing, it will need to be removed. Use a utility knife to cut away any roofing felt or underlayment that's covering the flashing. Then, carefully remove the flashing without damaging the shingles or the chimney.

### Step 3: Prepare the Surface
Clean the area around the chimney where the new flashing will be installed. Remove any debris, old nails, or tar. Ensure the surface is smooth and free of any material that could interfere with the adhesion of the new flashing.

### Step 4: Cut the Flashing
Measure and cut the flashing material to size. You'll want a piece that extends at least 4 inches past the edge of the shingles on all sides of the chimney. This ensures adequate coverage and protection.

### Step 5: Position the Flashing
Place the flashing around the chimney so that it overhangs the roof edge. The bottom should sit on the roof, and the sides should wrap up and around the chimney.

### Step 6: Secure the Flashing
Using **four evenly spaced 1-in. galvanized roofing nails**, secure the flashing to the front edge of the chimney. This will hold it in place while you work.

### Step 7: Install the Drip Edge
Install a drip edge along the lower edge of the flashing to direct water away from the chimney and prevent it from seeping behind the flashing.

### Step 8: Shingle Up to the Flashing
Once the tearout and cleanup are complete, shingle up to the bottom of the chimney. Ensure the shingles are properly aligned and sealed to create a watertight seal.

### Step 9: Seal with an Ice-and-Water Barrier
To provide an additional layer of protection, seal around the chimney with **12-in. wide strips of ice-and-water barrier**. This material is designed to bond to both the roof and the flashing, creating a waterproof seal.

### Step 10: Final Check and Clean Up
After the flashing is installed and sealed, do a final check to ensure everything is secure and watertight. Remove any tools, debris, or excess materials from the roof.

Flashing a chimney is a meticulous process that requires attention to detail and the right materials. It's always recommended to consult with a professional if you're unsure about any part of the process. However, with the right knowledge and tools, it's a project that many homeowners can tackle with confidence.

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Pound four evenly spaced 1-in. galvanized roofing nails through the front edge of the flashing to hold it in place. Once you complete the tearout and clean up, shingle up to the bottom of the chimney (Photo 2) and seal around it with 12-in. wide strips of ice-and-water barrier.read more >>