Simpson Dura-Plus Chimney Life

History: I have a 6" Simpson Dura-Plus Triple-Wall chimney that I installed myself in 1988 along with my CDW 246CCL. I'm about to replace the CDW, leaning strongly toward a Progress Hybrid.

The Dura-Plus chimney has three layers, with ceramic insulation between the two inner layers to keep the inner flue warm, and an air space for cooling between the middle and outer layer in the event of a chimney fire. It is all installed in a protected space within the house except for the top two feet that extends above the roof line. The inner flue is stainless and the two outer layers aluminized and galvanized steel respectively, except for the top exposed section, which is stainless on the outside.

The tirple-wall design is supposed to prevent damage to the inner flue in the event of a chimney fire, which I believe happened only once not long after I originally installed the stove. Each year I sweep the chimney from above with a steel brush, and then look down with a flashlight. So far it has always looked good, with no warpage or splitting evident. (The chimney is straight all the way down to the stove connector, so pretty easy to inspect.) The Dura-Plus has a 25 year warranty, which just expired last year.

So my question is - can I get more good years out of this chimney, or should I consider replacing it when I install the new stove? I'm not excited about the added cost, but I don't want to burn the house down, either. What do y'all think. Is there any reason the current chimney can't last for a number of additional years, assuming I don't destroy it in a chimney fire?

johnstra said:

I also have a Dura-Plus chimney and I've heard from several sources it's not the best system. The inner chamber has much less insulation than the double-walled product and therefore the triple-walled flue ends up running cooler. For EPA stoves that can run with lower flue temps this can result in less than optimal performance. So far, with my BKK, stove performance is great but I do have much more creosote in the upper part of my chimney than I would like to see. If I had it to do again, I'd have gone with a double-walled product.

It seems a shame to replace your chimney if it's in good shape, but keep the above in mind. Maybe have it inspected by somebody you trust. If it's close to EOL that will help you decide.

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I've never seen a whole lot of creosote with my CDW running, except just under the chimney cap in the exposed section of the chimney; but that was only when I was running the stove at very low burn rates, which I no longer do. Maybe I'll call a good chimney sweep this year to clean the chimney and get a second opinion. Problem is I've been doing it myself since I installed it, so I don't know anyone whom I can trust.

begreen said:

I'd have a certified sweep camera check it. If it is still in good shape it may have years of service left.

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Thanks, begreen. I think you are right. I will do that before I install the new stove.