Want to build a mason chimney

coalder · Post by **coalder** » Sat. Mar. 07, 2020 11:57 am

Chancey, I have be pondering your new endeavor with much deliberation, along with some research. And am here to highly suggest that you use conventional 8x8" flues instead of 6" round. Sometimes people split hairs so fine that they cut their fingers off!! I can elaborate here on the forum, or send you a PM as to the logistics.
Also be acutely aware that just because you have a block foundation 8" solid masonry is required around both flues. Thus you will have to cut an approximate hole in your wall 24" x 44" to accomplish this; along with floor beam support.
Jim

Hoytman · Post by **Hoytman** » Tue. Apr. 28, 2020 10:30 pm

I’d like to here your comments on six inch flues.

I know a guy that’s considered a “stove guy” and a forum “guru” on two other forums. His explanation to me when discussing 6” versus 8” flues in the context of modern wood stoves versus old pre-epa wood stoves was that today’s recommendations of 6” flues from stove to the top of the chimney would not only work, but was and is the best choice. Not only for modern wood and stoves, but the 6” flues would also work on older 8” outlet stoves and cause them to perform better.

He said most of those old wood stoves had a large outlet because many of them were used in old fire places of the day...which in that context...most flues were much larger in those days and needed the 8” outlets to keep chimneys burning cleaner. He says this goes for coal stoves too. His thoughts were 6” outlets and chimneys will work for nearly every home today and he recommends lining all chimneys to 6”.

This guy is a major Fisher wood stove collector. Has coal stoves too, antiques, wood and coal cook stoves, and tractor trailer loads of stoves and parts. He is considered a Fisher wood stove guru on a couple forums and I think he’s the guy that started the Fisher forum on the hearth dot com website.

After giving his recommendations a lot of thought I’m not sure I can disagree with him. He says that any stove will perform well, even better, with a 6” chimney because of less space to heat...at the top of the chimney. He also says for wood, that most people use a magnet and look for 250*F-300*F temps. He says that’s the wrong place to look or monitor the wood stove pipe for creosote build up. He says to check for 250*F chimney temps outside at the top of the chimney...temp taken and wanted inside the chimney...250F. Once that temp is measured on the inside of the chimney at the top measured from on top of the roof, then go back down and see where the magnet thermometer says and use that point of reference. That makes sense for wood also. He even likes Hitzer stoves too and has one. Loves it.

Hambden Bob · Post by **Hambden Bob** » Wed. Apr. 29, 2020 5:48 am

Now this is what I call a Truly Liberating Off-Season "Smash It Out" Thread! You just never know what You're Inspiring in Others that have been putting up with the same Dilemma,and are now "Going For The Throat" to Smash It Out! Come first fire in Da' Fall,it'll all be worth it!!

Post by **Rob R.** » Wed. Apr. 29, 2020 7:27 am

Hoytman wrote: ↑
Tue. Apr. 28, 2020 10:30 pm
I’d like to here your comments on six inch flues.

I know a guy that’s considered a “stove guy” and a forum “guru” on two other forums. His explanation to me when discussing 6” versus 8” flues in the context of modern wood stoves versus old pre-epa wood stoves was that today’s recommendations of 6” flues from stove to the top of the chimney would not only work, but was and is the best choice. Not only for modern wood and stoves, but the 6” flues would also work on older 8” outlet stoves and cause them to perform better.

He said most of those old wood stoves had a large outlet because many of them were used in old fire places of the day...which in that context...most flues were much larger in those days and needed the 8” outlets to keep chimneys burning cleaner. He says this goes for coal stoves too. His thoughts were 6” outlets and chimneys will work for nearly every home today and he recommends lining all chimneys to 6”.

This guy is a major Fisher wood stove collector. Has coal stoves too, antiques, wood and coal cook stoves, and tractor trailer loads of stoves and parts. He is considered a Fisher wood stove guru on a couple forums and I think he’s the guy that started the Fisher forum on the hearth dot com website.

After giving his recommendations a lot of thought I’m not sure I can disagree with him. He says that any stove will perform well, even better, with a 6” chimney because of less space to heat...at the top of the chimney. He also says for wood, that most people use a magnet and look for 250*F-300*F temps. He says that’s the wrong place to look or monitor the wood stove pipe for creosote build up. He says to check for 250*F chimney temps outside at the top of the chimney...temp taken and wanted inside the chimney...250F. Once that temp is measured on the inside of the chimney at the top measured from on top of the roof, then go back down and see where the magnet thermometer says and use that point of reference. That makes sense for wood also. He even likes Hitzer stoves too and has one. Loves it.

I agree with not having an oversized flue, but would suggest following the recommendation of the stove manufacture - that way you won't have an argument with the code officer, or a poorly performing stove. I also suggest insulating the flue with vermiculite.

freetown fred · Post by **freetown fred** » Wed. Apr. 29, 2020 8:37 am

With 6" ya get more draw---like doin water goin from a 1" pipe to a 1/2" pipe except reversed. I know that's pretty simple & not easy to understand-------

McGiever · Post by **McGiever** » Wed. Apr. 29, 2020 9:28 am

Simple can always work when one size fits all...but no 2 masonry chimneys are the same though and don't forget that stoves come in many flavors also.
It dangerous to persuade people to try a borderline install just because one person says he pulled it off. The rest of us may not be so lucky.

Then maybe the statements made that 6" works might have lost it's true meaning in the translation...was actually meant for 6" 22 ga. metal stove pipe and statement was never really meant for any masonry chimney??? Would not it be difficult to open the loading door at reload for a stove connected to a under performing chimney??

A finished masonry chimney that under performs is no easy fix...you've been warned...

Hoytman · Post by **Hoytman** » Wed. Apr. 29, 2020 12:27 pm

Rob R. wrote: ↑
Wed. Apr. 29, 2020 7:27 am
I agree with not having an oversized flue, but would suggest following the recommendation of the stove manufacture - that way you won't have an argument with the code officer, or a poorly performing stove. I also suggest insulating the flue with vermiculite.

I would agree with that...

However, I think he explained that in the context of having or using an old wood stove with a big 8" outlet, then a home owner hiring a chimney sweep to replace a liner because technically the sweep is supposed to stay with what the stove outlet is.

This guy was saying if you replace it yourself, use a reducer at the stove and use 6" all the way out for better draft and the stove/chimney fill function better together.

freetown fred · Post by **freetown fred** » Wed. Apr. 29, 2020 12:44 pm

I've been burnin wood or coal for 55 yrs All types of stoves--from Glenwood pot belly, Old Country Comfort kitchen stoves to Hitzer hopper fed & have found that the 6" pipe on any of them--6", 8", 7"--whatever-- ya get a better draw--AND--this is from experience, not hear-say-- YES, I'm talkin hand fed--not them thar fancy girly stoves!

Hoytman wrote: ↑
Wed. Apr. 29, 2020 12:27 pm
I would agree with that...

This guy was saying if you replace it yourself, use a reducer at the stove and use 6" all the way out for better draft and the stove/chimney fill function better together.

Hoytman · Post by **Hoytman** » Wed. Apr. 29, 2020 12:49 pm

Then you two old birds would agree. The guy's name is Paul...lives in eastern PA and goes by "Coaly" on other forums. He's a treasure trove of knowledge. Of course, Fred...I wouldn't want to leave you out of that mix. LOL!!!!

coalder · Post by **coalder** » Wed. Apr. 29, 2020 6:06 pm

Ok guys, here ya go. Sorry I missed this yesterday. Will a 6" flue draw a tad better? YES. However when you do this you are violating codes, & God forbid something goes wrong & ins gets involved. This is with an 8" breach. Now to get 275 at the top of flue requires damn near a chimney fire. As gasses cool a LOT going up the chimney. You would have to burn that stove extremely hot to achieve that. That's why with wood creosote forms more at the top. An appliance with a 6" breach into a 6" flue will draw better than a larger flue. However I have heard enough about using 6" round masonry thimbles as flues. This concept defies reasoning!!! Am 66 yrs old & been doing this professionally all my adult life, & can tell you that I have never encountered a round flue masonry chimney. And neither have any of my mason colleagues. That is why flues are described as rectangular or square & thimbles are round. There are many dynamics involved. So you use a round horizontal tile To a round vertical tile; Think about the compound cuts & how the vertical pipe is weakened. Code also says the thimble must penetrate the flue. How do you do this with a 6" round to round? Also, say you have some sort of failure, you are done. This 6" terracotta can't be relined, so what now. A properly built masonry chimney with an 8x8 flue will draw just fine as evidenced by Bill's approx 10ft chimney. So no need to compromise ones self & do something foolish like using thimbles as flues just because ya read something somewhere. Chances are the author never held a trowel.

Jim

Hoytman · Post by **Hoytman** » Wed. Apr. 29, 2020 9:05 pm

http://www.sandkuhl.com/thimble%20size%20chart.htm

Hoytman · Post by **Hoytman** » Wed. Apr. 29, 2020 9:07 pm

http://www.sandkuhl.com/flue.htm

coalder · Post by **coalder** » Wed. Apr. 29, 2020 9:49 pm

Hoytman wrote: ↑
Wed. Apr. 29, 2020 9:07 pm
http://www.sandkuhl.com/flue.htm

Never heard of a flue tile that was totally freestanding & did not allow any mortar to touch it for need of expansion. Nothing to support the flue latterly , meaning slightest movement, and there will be some, will break the seal from flue to flue. The cap also needs to be poured with an expansion joint between it & the flue, then sealed with silicone. Hmmm pretty shaky to me. Also couldn't find any links to it here in NY. Maybe that's why I never heard of it?

Their specs also defy code by stating that the thimble could but the flue as an alternate. Not so at least in NY.

And again I will reiterate; what happens in the event of a failure with a 6"round liner?

In the famous words of the immortal PT Barnum "there is a sucker born every minute".

Jim

Hoytman · Post by **Hoytman** » Wed. Apr. 29, 2020 10:08 pm

I hear you on that. I like my 8”x8” as it does fine. Actually, with coal it did better than I was told it would do being so short.

I may re-line it with same layer this spring. Some of mine the joints aren’t flush...quite bad actually...and they have no mortar...just sit flush with each other. It’s been there since ‘54. Truthfully, the one cracked liner is really all that’s wrong with it.

I could coat it with HeatShield, but I think I could replace them all myself way cheaper and extend it a little.

8” round would be fine too, but why bother.

coalder · Post by **coalder** » Thu. Apr. 30, 2020 8:04 am

Hoytman wrote: ↑
Wed. Apr. 29, 2020 10:08 pm
I hear you on that. I like my 8”x8” as it does fine. Actually, with coal it did better than I was told it would do being so short.

I may re-line it with same layer this spring. Some of mine the joints aren’t flush...quite bad actually...and they have no mortar...just sit flush with each other. It’s been there since ‘54. Truthfully, the one cracked liner is really all that’s wrong with it.

I could coat it with HeatShield, but I think I could replace them all myself way cheaper and extend it a little.

8” round would be fine too, but why bother.

Bill, save your money. Many guys years ago built chimneys & never mortared the flues. They probably figured all the mortar oozing from the bed joints sealed the flue well enough. At least your chimney has a flue. My chimney also has a cracked flue & just something that I am willing to live with. I know this is a lot easier said than done; but in your case I might consider adding a couple of feet to your chimney, just to see ifn it helps to idle down that big stove of yours. I really don't know for sure if it would, but just a thought as it might.
Jim