Chimney liner 101....need a lesson on the different types of liners

[rwhite]

The insert is ready, the flue is clean and I'm ready to order the liner. But there are a few types and I don't fully understand the differences and applications. What I'm working with is a exterior masonry chimney. 20' tall and an unlined flue that is 18"x18". Pretty much a straight shot to the stove but the liner will have to make a bend to clear the damper opening.

1. It seems that 316ti and 316L are common materials for liners. Which is better?

2. Should I get 1 ply or 2?

3. What thickness? It would seem that the thicker the better but will I run into problems bending it? There seems to be .005, .006, and .013 thickness available.



Last question is about the smoke shelf in the chimney. After I cut the damper out and opened up the hole I was able to get a shop vac back in there. I vaccumed out a load of junk and probably 75 years of chimney cleanings. Should I try and get some concrete or sand back in there or just leave it alone since I am lining anyway? Opening behind the smoke shelf is probably 1' deep and the width of the firebox (28").

 

[WoodpileOCD]

Guess I'll jump in on this as well with a question. Not trying to hijack your thread OP but I think you'll benefit as well from any answers we get.

Same situation and I'm looking at the Rockford liner kit and the Flex King from Chimney Liner Depot. Anybody have a reason to go with one or the other? Rockford is about $100 more but gives more options on the rain cap and top plate. Also any opinions on rain caps and top plates. Picture is of my options from Rockford but pretty much the same at other places. I have a clay liner in the chimney 12x12 inside diameter but don't know if the extra money for a terra cotta cap is worth it. Have a question out to BrotherBart on another thread as to why he thinks it is as he just replaced two of the cheaper ones with the TC ones.

 

[Jackfre]

I would recommend you look at MD Dura-Vents Dura-liner system. You have plenty of room to accommodate the pipe and it is pre-insulated and has a good warranty. It is 304 SS I believe. When I removed the insert at my home, I found an old Dura-liner system in excellent condition. While I've had no affiliation with DV for over 20 yrs I did represent them when this system was introduced in the mid-80's. One of the things I liked was the 4' sections of round or oval pipe. My current system is oval and the transition thru the damper section is oval as well. This is a very good product and one you can do yourself. I've done coil liners too and have spent a lot of time on roofs. I absolutely was more secure in the air with the shorter sections I could handle. Good luck on your install.

 

[WoodpileOCD]

Thanks Jackfre
I looked at them but from what I can determine it only comes with any warranty at all if it is 1. Installed by a certified technician and 2. Inspected, cleaned and documented every year by a certified tech. Since this will be a DIY project and I don't fancy paying someone every year to clean my chimney (been doing it myself for a long time) it seems that I wouldn't have a warranty. I like the product and the concept of a double wall with insulation and it does look like a great system. Thanks.

 

[begreen]

Here's an uber-link to lots of good posts on Hearth.com, sorted by topic. About 2/3d down you will find a set of links on liners.

https://www.hearth.com/econtent/index.php/forums/viewthread/65174/

Based on the description I would consider putting in an insulated, rigid liner with a flex connector at the damper. I'd also recommend a damper-sealing block-off plate to reduce insert heat loss to the mass of masonry.

 

[rwhite]

Lots of good info on those threads but nothing that answered my questions. Thanks BeGreen for the recomendation of the insulated rigid liner. But alas I am the slow kid in the class that never got sharp scissors. So what is the advantage of rigid over flex? Rigid seems more expensive in the length that I need. Why would one use 2 ply instead of 1? (other than it wipes cleaner...does this apply to the stove pipe as well?).