Snow Diverter/Dam for Woodstove Chimney Installation

You can find snow deflectors at any roofing supply house

The Duravent instructions suggest a "splitter" above the flashing in heavy snow areas. They don't supply one but show a sketch of one to be made from sheet metal.
It's essentially a "dormer" on the uphill side of your chimney. You can see the sketch Fig. 14 in their installation instructions.

You will also see them referred to as "Crickets"...vee-shaped deals a few inches high that are fastend to the roof on the "uphill" side of the chimney with the point of the vee facing up toward the ridge. When snow begins to migrate down the roof, it will be deflected around the chimney. Rick

Whether or not you need one depends on how much roof there is above the point at which your chimney penetrates, how tall the chimney is above the roof, and just how much snow your area receives. If your chimney is low on the roof, is tall, and you get a lot of snow, then this is an excellent idea. Rick

If you live in a high snow area, that's a good idea. We've had more snow than normal over the past 2 winters. Last year was terrible--we got over 8 ft on the valley floor (some of the mountains got over 30 ft) and there were a number of roofs that collapsed due to snow load. Virtually everyone had to clear their roofs at least once (I was up on mine twice). I've seen these cropping up on a number of roofs this spring and summer. . A number of people with metal chimney pipe have also put up guards like this .

We generally get 30' plus. One of the reasons we are snowed in on most winters. I have a 12-12 pitch and have found that a good strong cricket is the way to go. Just do not make it to small. Ours is 3' at the high spot near the chimney. One other point is to make it very close to the chimney say 3 or 4 inches. This system will prove inadequate if the cricket is not of sufficient size. Do not worry the cricket will look huge on the ground but fine once up on the roof. I have a painted galvanized roof and I built the crickets myself. Remember to fasten the cricket "very" well.

Larry, good for you for thinking about this now! Rick