Are currently dealing with a leaky chimney? Perhaps you have tried your best to find the culprit, but have always come up empty handed. Chimney flashing leaks are among the most difficult to find and repair simply because of the way flashing is installed. Today I’m going to go over the purpose of chimney flashing, how to identify it, and how to install new flashing if you intend to attempt it as a DIY project; which I do not recommend unless you’re a general contractor or have a lot of experience in construction.
More often than not, chimney leaks occur because of an improperly installed flashing. If you get up on your roof sometime and examine the sheets of metal surrounding the outside of your chimney, you will have found the flashing.
Chimney flashing is made up of two pieces of sheet metal, an L-shaped piece that connects to your roof and another that connects to the chimney itself. Take a look at yours and see if you can see any rust or other damage. If you do, then you will need to replace it. So how do you put in a new one?
The first thing you will need to do is remove the old flashing from your chimney. Make sure that once you have cleared away the metal, you clean and scrape away any old flashing or other cement that could impede the new installation. Remember that water takes the path of least resistance, so if there are any gaps, your entire flashing replacement has been negated.
Once this is done, you will be ready to install your new flashing. You should be able to find all the hardware and tools that you need at your local hardware store. You will even be able to get sheets of metal that can be customized to fit your chimney.
Your new flashing can be installed in just a few easy steps.
- Cut Base: Using tin snips you will need to cut the flashing to fit the base front of your chimney. Then bend one side of the flashing around one edge of the chimney.
- Secure Base: Fit the flashing up against the front of the chimney so that one side of the metal lies flush with your roof shingles. Clip the edge of the flashing that lies against the other side of the chimney with your tin snips. Bend this around the edge of the chimney as well before hammering galvanized roofing nails into the metal lying flush against the roof being careful to space them evenly.
- Attach Corner and Step: Fit piece of square step flashing over the front corner of the chimney. Hammer two roofing nails over the flashing into the roof. Nail a shingle over the flashing. Place second piece of flashing overlapping the first one and secure it with a nail. Do the same thing for all corners.
- Chimney Saddle: Secure the saddle over the back part of the chimney with nails. Place shingles overtop of the saddle and nail these down into the roof.
- Install Cap Flashing: Saw grooves into the mortar joints before you fit the front cap flashing around front of chimney. Insert the flashing’s flange into the grooves. Drill a hole into the chimney front and secure it with a plastic anchor. Repeat on each side of the chimney making sure that each piece of flashing overlaps.
I hope this is helpful and all the best installing your flashing! If you’re not comfortable taking on a job of this magnitude, I’d be glad to handle it for you. Just give me a call at 610-626-2439 for a consultation and quote.