7 Chimney Roof Flashing Installation Tips 7 Chimney Roof Flashing Installation Tips

Roof flashing around the chimney of your home is an important part of protecting your roof against water damage. Because the chimney comes out of the roof, there is the potential for water running in between the shingles and the chimney into your roofing system. Installing roof flashing for your chimney is not a difficult project and can be done with basic tools and materials. If you have a chimney that needs to have some roof flashing installed, or replaced, here are some tips to help you with the project.

1 - Wear Thick Gloves

Safety is important when working with any type of metal flashing. The metal flashing is a thin piece of sheet metal, or aluminum, that has sharp edges. These sharp edges are even more dangerous when you are cutting the material to fit. Wear heavy duty gloves that will withstand any cuts that the sheet metal can make. 

2 - Remove any Obstructions

Applying roof flashing for a chimney requires that the metal be conformed to the approximate shape of the chimney. This will help to keep any water from leaking because of air gaps. To do this, the surface of the roof, and the chimney, should be clear of any debris or obstructions. If there is flashing in place currently, remove it before adding the new piece. Remove any nails, old caulking, branches, dirt, or loose cement. 

3 - Use a Cricket

A cricket is a very useful item when installing roof flashing around a chimney. The cricket is a small piece of plastic, rubber or metal, that has a slight angle that the flashing is laid on. This will angle the flashing away from the chimney that will better direct the rain, snow and ice down the roof instead of sitting next to the chimney. If there is already a cricket installed, but it needs repaired, fashion a new one out of metal.

4 - Use Tin Snips to Make Cuts

Tin snips are the best tool to use when working with metal flashing. The thickness of the metal flashing is more than a utility knife can cut through, but too thin for a circular saw. The tin snips are also better for overall control of the cut. However, it must be restated that safety is important when cutting the flashing. Use gloves, long sleeves, and eye protection. 

5 - Cut Flashing Large Enough for Chimney and Roof

When cutting the flashing you need to make sure that there will be at least 6 inches of coverage on the chimney itself and 10 inches of coverage on the roof. This must be one piece and not two pieces for a continuous protective barrier. 

6 - Bend Flashing Carefully

Once the roof flashing for the chimney is cut you will need to bend it to conform around the chimney. In the corners of the chimney, make small cuts in the flashing so it will bend around the corner easier. Use a soft mallet to bend the flashing so it sits flat between the chimney and the roof. Bending it too quickly may cause the metal to crack.

7 - Use Roof Nails and Caulk to Seal

Once the flashing is bent around the chimney, roofing nails will secure it to the roof. Use a waterproof caulk to seal the edges and the nail heads. 

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