Replace Metal Chimney Flashing Easily

You know that your metal chimney flashing needs to be repaired when that area on your ceiling is showing signs of moisture. Replacing chimney flashing is not impossible to do on your own. Here are simple steps.

Tools and Materials Needed:

  • Galvanized chimney flashing (8 inch)
  • Galvanized step flashing (Pre-bent)
  • Roofing nails
  • Flat bar
  • Hammer
  • 100% silicone caulking

Step 1 – Remove

Remove the singles up to 15 inches away from the chimney. Take out old nails and metal flashings, and scrape off roofing cement.

Step 2 – Make the Starter Strip

Make a starter trip by cutting galvanized flashing that is 10 inches longer than your chimney's width. Bend the flashing horizontally, following the angle of the chimney and roof intersection.

Step 3 – Cut and Nail

Five inches away from the chimney's edge, cut the flashing (downward only) up to the corner that touches the roof. Bend this cut portion backward and flatten against the roof.

Nail the flashing into the chimney. No nails should go into the roof. Put back the shingles to cover the flashing's front part.

Step 4 – Step Flashing

Work your way up the chimney with the flashing bent, following the roof-to-chimney angle. Alternately nail the flashing and shingles, each one overlapping the other as you work your way up. The flashings should be completely invisible under the shingles. Once you reach the higher part of the chimney elevation, repeat Step 3.

Step 5 – Seal

Seal the shingles' edges, applying a small amount of silicone caulking. Caulk heavily the corners or areas where new chimney flashings do not overlap.