How to Install Metal Chimney Flashing

Metal chimney flashing prevents leaking by providing a barrier of metal where the chimney and roof meet, because the flashing protects the chimney and the roof from water damage. If flashing isn't installed, leaks can develop, resulting in expensive repairs. The best way to prevent it is to install metal flashing.

Supplies

• Measuring tape


• Roof flashing


• Pad


• Pencil


• Tin snips


• Hammer


• Roofing nails


• Silicone sealant 


• Caulk gun


• Caulking Tar (optional) 

1. Measure the length and width of the chimney.


2. Use a pencil and paper to record the figures.


3. Trim the metal flashing pieces for the roof with the tin snips.


4. Cut it 12-inches longer than the measurement.


5. Set the cut piece in front on the lowest side of the chimney.


6. The metal must lay flat against the roof, fit up to the base of the chimney.


7. Make a flange of six-inches on the ends. The bend will be about a 90-degree angle, when completed. Repeat this process for all four corners of the chimney.


8. Install the flashing lying flush with the roof at all installation points on each side.


9. Nail the flashing to the chimney and the roof with the roofing nails to hold everything securely in place.


10. Use the calking gun and silicone sealant to caulk each of the nail holes on the flashing, for a throroughly covered area, as well as very secure.


11. Apply caulking around the corners of the chimney where the metal meets each piece to seal the joints. As an alternative, tar can also be used.