Chimney pipe: one long vs multiple short pipe sections (for ease of cleaning)?

[MaybeErnie]

When installing chimney pipe through the ceiling/roof, is there some reason why having a single long length (5') is better than having two sections of, say, a 2' + a 3' length? If either is fine, it would be very handy for me to be able to disassemble the two terminal sections for ease of cleaning. Trying to reach up to the top of a 5' length to run a brush and rod down it would be pretty tough on this roof, even from the uphill side.

I'm wondering whether the 2 sections would become tough to separate once the chimney has been used for a while. In case it matters, this will be double-wall DuraVent DuraTech pipe with the twist-lock connection at the joints. I also read that it's advisable to have the final piece (the one with the chimney cap on it) be a short section because that is the piece most likely to degrade and need replacement from smoke damage. True?

 

[Whitenuckler]

When installing chimney pipe through the ceiling/roof, is there some reason why having a single long length (5') is better than having two sections of, say, a 2' + a 3' length? If either is fine, it would be very handy for me to be able to disassemble the two terminal sections for ease of cleaning. Trying to reach up to the top of a 5' length to run a brush and rod down it would be pretty tough on this roof, even from the uphill side.

I'm wondering whether the 2 sections would become tough to separate once the chimney has been used for a while. In case it matters, this will be double-wall DuraVent DuraTech pipe with the twist-lock connection at the joints. I also read that it's advisable to have the final piece (the one with the chimney cap on it) be a short section because that is the piece most likely to degrade and need replacement from smoke damage. True?

Would you be able to clean it from the bottom only?

 

[MaybeErnie]

Would you be able to clean it from the bottom only?

That would be tough -- the stove is on the bottom floor of a tall 2 story house. I actually had to retire another woodstove (an insert) because it was so hard to clean from either end. For this new install, it would be far easier to tackle it from the top as there is an upper deck that gives access to the roof close to where the pipe will sit.

 

[Whitenuckler]

That would be tough -- the stove is on the bottom floor of a tall 2 story house. I actually had to retire another woodstove (an insert) because it was so hard to clean from either end. For this new install, it would be far easier to tackle it from the top as there is an upper deck that gives access to the roof close to where the pipe will sit.

I think it would be safer to use some short sections for sure. I don't think those twist off ones would be too hard to take off. The only issue would be the making of some sort of strap/jig to hold the one lower from twisting as well.

 

[Murray01]

I’d go 2 shorter sections for ease of cleaning. They will come apart you just have to watch that the top section only moves as you disconnect it. If anything other than the top section moves when disconnecting you will need a helper to hold the second from top piece or use a 2X4, a ratchet strap and your thigh to hold the second from the top from moving.

 

[MaybeErnie]

Good points! I imagine I could rig a big ratchet strap or something to hold the bottom section from rotating.

 

[Murray01]

Back in the mid 1990’s Selkirk recommended putting a sheet metal screw in the threaded flange to prevent unintended unthreading of chimney sections, the current instructions make no mention of a single screw. If all the sections, except the top section had one screw then you wouldn’t need to worry about inadvertently unscrewing 2 or more sections. I’m not suggesting you put in one screw since the manufacturer doesn’t mention and I’m not experienced enough to make that suggestion.

I just reread your initial post, I had one heck of a time removing the top section of Class A chimney after 20 years of never being apart. The top section of pipe had more buildup of creosote than the rest(cooler fuse gas) but wasn’t degraded compared to the rest of the chimney. A more experienced eye might have seen some degradation but I didn’t.

 

[MaybeErnie]

Yes, having a screw at the joints, would solve the problem of inadvertently rotating multiple sections, but as you said, I don’t think I’m supposed to do that with this twist-lock pipe. It’s good to hear that your top section didn’t appear to be too degraded after 20 years. That’s encouraging!

 

[Whitenuckler]

Here is what begreen suggested to someone who had to take his chimney apart by himself:

"Can you ratchet strap a 3' piece of 2x3 at a right angle onto the next lower section to hold it? Let the 2x3 bump up against you to stop it."

That worked, and he got it apart. I think if you take the sections apart each year and clean the ends, you should be OK.

 

[MaybeErnie]

That’s a good tip, I’m probably gonna go ahead and order this pipe later today. I appreciate the help thinking it through.