I need to replace wood stove chimney at our cabin. Strong winds in November toppled a large spruce, and one of its branches knocked off our chimney right at the roof line. I've used a silicone-rubber-gasket type chimney flashing successfully in the past. However, friend of mine who's a small scale construction/remodeling contractor recommends the sheet metal type. Those have leaked a little for me in the past. The chimney is 6" inner diameter stainless double wall. Any thoughts?

Is it leaking around a seam in the pipe itself or under the roofing material?

The leaking was in the distant past, but I think it was where snowmelt backed up under the flat part of the metal flashing. The current job at hand is replacing the chimney where it passes through a pitched metal roof.

I guess it depends of if you have shingles or metal. Being a bricklayer, I've built a lot of chimneys and I'd much rather deal with a shingled roof than one covered with metal. So much easier to get weathertight. Are you using a prefab through-the-roof type connector?

I have a prefab metalbestos chimney my coal stove is connected to. It vents through the wall. I used it only because I didn't have time to build an outside chimney.

I was a little suspicious of the rubber or I guess maybe it's a type of neoprene; but over the past 17 years that I have been using the stuff on a couple of different cabins I've had better luck with it than I have in the past with sheet metal or lead flashing.

I would recommend a EPDM roof flashing and use all the screws your supposed to for installation. They contour to the shape of the metal roofing. I also install some 1 1/2” metal angel in a V shape above the flashing to help protect it from snow/ice damage.

Also remember not to over tighten the metal roofing screws on the rubber washers. Just tight enough to make the rubber washer have good contact with the metal roofing. You don’t want to make the washer bulge or it will fail. I recommend using a cordless drill with torque settings. My buddy had a garage built last fall and the contractor put on the metal roofing with a impact driver. He called me and has the roof leaking every where to many to count. Good thing he hasn’t finished off the inside yet. The metal roofing screws have to all be replaced.

the most important, thing is snow guard , so snow don't slide an push against chimney

Thank you all. The rubber type flashing is a silicone based rubber and rated for the temp on outside of chimney. I think that's what I'm going to go with again. The pipe and chimney will be metalbestos type. Can't remember the brand. This is where part of my Corona virus stimulus check will go.