Improving curb appeal of chimney counter- (cap) flashing. Caulk or silicone?


Finally got a chance to work on my counterflashing for the chimney. The temporary caulking job I did for step flashing did a good job, but wanted to permanently complete the flashing job with angle grinder, copper, metal brake, and mortar. Unfortunately came to a realization that masons are human too by installing bricks in an imperfect position. Thus, no matter how much I bend copper to create a tight squeeze, there is always a small gap between each flashing piece due to variably positioned bricks. The very last one especially. See below.

Not terrible by any means, but ruins the curb appeal. I was thinking about using clear caulk or silicone with temporary weights while it dries to eliminate gapping. I will caulk only on the sides, of course, no caulking on the bottom since water needs a way to escape. Is that a reasonable thing to do or will it lead to something unexpected? I really like to dab a small amount of silver solder between each step, but I fear I may burn the house down or make a mess with the solder. Most European installations make cap flashing steps as one piece of lead or copper, so I doubt using either silicone or solder would make any issues. So long as cap flashing and step flashing remain unattached to each other and free to move. But my worry with silicone is that the part under it will remain shiny while the rest of copper will patina. That will leave quite visible lines which I am trying to eliminate in current situation with visible gaps. If I left it as is, I worry any high wind will be more likely to bend it away and it looks unsightly. Any thoughts on the standard of practice?


Its too late now but you could have put a flat lock joint on each piece to help hold them tight together. But honestly at this stage I’d say just leave it as is. You did a really good job probably already the best looking chimney flashing in the neighborhood.


Looks great, Just need a few rivits in the overlaps to tighten it all up. Don’t go gooing your nice work all up. In the future, a 1/2" hem on the verticals will greatly stiffen the faces.


Thank you all for encouraging feedback. I think I need to invest in a riveting tool, because it seems most copper work would greatly benefit from a rivet. I enjoy soldering copper, but I always have a messy (but functional!!!) product, so I resort to soldering only on an off-roof surface so I don’t burn a hole in something… Haha.

I followed Masons Contractors Association of America recommendation that stated " In higher quality work, the bottom 1⁄2 or 3⁄4 inch is turned under 180° to provide a stronger, smoother edge (sometimes called a hem)." I did about 1/4-inch hem on bottom, feeling that would be sufficient. Then I thought, why not hem the vertical sides too? But then got to doubting myself, worrying it would add bulk to the flashing. Yet, it would have created a sturdier and probably prettier final product. This is the second time I ignore my instinct in this entire roofing project and end up regretting it. I still have the counterflashing to do for the upper roof meeting chimney, I will definitely incorporate these recommendations there. Appreciate all of your recommendations once again, I would not have been able to have as good of a project without everyone’s valuable feedback.


Good job. If you cant resist hemming the vertical next time make sure you hem it in. You will go bonkers looking at the gap if you hem it out.


20$ for a rivit gun and less than 10$ for 100 copper rivits would be a good investment. Rivits in the counters will also keep wind from loosening then over time. You can use #42 rivits if riviting counter to counter or use #44 if you want to rivit both layors to the step flashing.


I just have to say that the copper is BEAUTIFUL! Good job!


Thanks everyone for the kind words and a wonderful suggestion to hem the sides as well as the bottom of cap flashing to improve rigidity. Although with imperfect brick work, the final product remains imperfect, the strength and the look of the final product is tremendous. I tried this method on upper roof and love the look of it. Once I finish shingling back of house, I will have entire chimney flashed and will post back the final product. This is so far my progress on the front side of upper roof in the image below. Once again, thanks everyone for all the feedback and suggestions, I am proud of this roof because of everyone’s help and guidance through amateur’s roofing struggles.