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How to Repair Flashing Around a Chimney

Flashing is installed at the point where the surface of a roof meets the chimney. However, if the flashing is damaged or not properly installed, it may cause your roof to leak. Interestingly, chimney flashing comprises two distinct layers, which are base flashing and cap flashing.

The base flashing secures the surface of the roof. Cap flashing partly covers the base flashing and has an L-shaped top that is inserted into the chimney.

To repair a chimney, you must construct a chimney saddle. This will direct water away from the chimney and allow it to flow down the surface of the roof. 

Don’t know how to do that? Follow the easy steps of how to repair flashing around a chimney discussed in this article. That being said, below are the important tools you will need to get the job done.

Tools Required

  • Galvanized roofing nails
  • An extension ladder
  • Shingle
  • Hammer
  • Chisel
  • New flashing (base, step, and cap)
  • Chimney saddle
  • Tin snips
  • Caulk

Step 1

Even though you can cut your flashing yourself, another alternative is to visit a sheet metal shop to have it done for you.

Step 2

With the aid of a hammer and chisel, remove the old flashing.

Step 3

Cut the base flashing to fit the chimney front using tin snips. In addition, bend one side of the flashing to cover one edge of the chimney.

Step 4

Place the base flashing against the chimney front and ensure it partly covers the roofing shingles. Using tin snips, clip the end of the flashing and bend it around the chimney. When you have done that, hammer 4 galvanized roofing nails into it to keep it in place. However, you must make sure the roofing nails are spaced properly.

Step 5

Cut an 8-inch or 20.3cm of step flashing and place it against the chimney front corner then set aside. After you have done that, pour a little drop of caulk at the point where the roof and chimney-corner meet. Now you can place the step flashing over the caulk and against the chimney-corner.

Immediately that is done, hammer two galvanized roofing nails into it to keep it in place. Using a hammer and roofing nails fix a shingle on top of the corner flashing. After that, place a second flashing of the same size against the chimney-corner.

However, you must make sure that the second flashing partly covers the shingle you have fixed. Once that is done, fix another shingle using roofing nails and a hammer over the second flashing. You must continue repeating the process until the chimney front is completely covered.

Step 6

Insert the chimney saddle at the back of the chimney. With a hammer and roofing nails, attach it to the roof. 

However, ensure that the roofing nails have a space of 6 inches or 15.2cm between them. Insert shingles along the flat area of the saddle. Don’t forget to nail the shingle and saddle to the roof. 

Step 7

The final step is to install the cap flashing around the chimney front. However, ensure that each piece of cap flashing partly covers the previous one. You must continue to repeat the process until it covers each side of the chimney. To finish the repairs, pour caulk over the mortar joints.


Since you know how to repair flashing around a chimney, it would seem quite easy. However if you know the right tools to use and how to do it, in no time you will fix your flashing chimney issues. Armed with this guide, you can repair your chimney flashing yourself without contacting a professional.



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