Chimney Problem Future Advice

[hayboy]

At 68 yrs old and after33 yrs of burning a train load of wood, I got problems. This chimney is a 8x12 clay liner with brick outside, from the 8 in inlet pipe to the top is approx 20ft. When I was able I brushed this out 2 or 3 times a yr, last 4 yrs son has done it. Hard getting him when it needs to be done. Chimney is showing a lot of cracks on the outside and we have been thinking about a new build of some sort. I am no professional engineer, and realize this is not a text book situation, and may have dodged a bullet all these yrs, but it has kept a two level house warm.Also thought about a high btu propane heater, but have enough wood to burn maybe 3 yrs. Please be nice to an old guy, need some honest advice and THANKS in advance.

 

[Kevin in Ohio]

Going by you have burnt for 33 years I'll assume you are burning dry wood and not water soaked? It would help a lot to know what kind of stove/furnace or if a fireplace you are using. If dry wood is being used, to have build up like that shows lack of air flow for a hot enough fire from my experience.

If you want to continue to burn and solve a lot of these issues I'd suggest looking into a catalytic type stove. Vermont castings is one brand. They are very efficeint and clean burning. They reburn the smoke so build ups are little to none. Require smaller pieces and from what I understand more frequent reloads but might be a great option for you. Maybe someone with one will give you the scoop.

You can get your current chimney relined with a stainless liner as well so that might be worth thinking about too. I know several on here have had that done. Sorry I couldn't be of more help but I'm running a boiler. Looks like you have several issues here.

 

[ChoppyChoppy]

You live somewhere warm? Looks like your yard is growing?

I ask because warm temps makes a decent draft tough so makes for a slow movement of smoke which us one cause of cresesote.

 

[hayboy]

Pickens Co Al, west central Al. It has been a warm winter. Chimney is 20 ft. tall and even with a super hot fire the temp of the smoke is too cool. Had a catalytic add on in the pipe a few years ago, it stayed closed up a lot and took it out. Stove is a big square firebox with a 8 in. horizontal pipe that runs about 3 ft. to the lined chimney. Thanks

 

[sirbuildalot]

I think it is time for an insulated stainless liner. Masonry chimney flues don't get as hot as stainless (especially an outside chimney) and creosote sticks easier. Plus the cracks can allow fire to spread into the house which can become very dangerous as it is a fire hazard. For an older chimney, that is the route I would take, and this is assuming the chimney is structurally sound.

 

[hayboy]

What kind of insulated liner could I put in a 8by12 with mortar protruding from some of the joints? Stove has 8 in, pipe.

 

[sirbuildalot]

Most of the ones I have seen installed used 6" pipe. To boot many of the burners had 8" outlets. I would have concerns as well as the typical rule is to not go down in size/diameter. My folks have a Jensen indoor woodboiler with a 8" outlet and had a 6" liner installed this past fall. They burn 8-10 cord a year (everyday of the burning season), and haven't had any issues as of yet that I have heard about. I'm interested to see how dirty it is when they clean it (haven't yet this season). If it looks good, I am installing a liner myself this summer. I have a 8" outlet on a old Thermo control and a 8 x 12 flue on the outside wall like you. I have to clean mine every couple weeks or it clogs up, and that's with seasoned clean wood. The creosote I'm getting tells me it cools off before it can exit the chimney. Very similar to the pic you posted. Big flaky chunks.

 

[Marshy]

At 68 yrs old and after33 yrs of burning a train load of wood, I got problems. This chimney is a 8x12 clay liner with brick outside, from the 8 in inlet pipe to the top is approx 20ft. When I was able I brushed this out 2 or 3 times a yr, last 4 yrs son has done it. Hard getting him when it needs to be done. Chimney is showing a lot of cracks on the outside and we have been thinking about a new build of some sort. I am no professional engineer, and realize this is not a text book situation, and may have dodged a bullet all these yrs, but it has kept a two level house warm.Also thought about a high btu propane heater, but have enough wood to burn maybe 3 yrs. Please be nice to an old guy, need some honest advice and THANKS in advance.

You have yourself a creosote issue! There's a lot of questions that need to be answered before you can get a good meaningful recommendation in my opinion. I'll throw some out there, you do your best to answer.

Have you had creosote like this before?
How long ago was the last cleaning?
Do you process your own firewood or purchase it?
How long from when its cut down and split before you burn it?
Do you have a moisture meter and do you know the moisture of your wood?
Do you have the ability to stack and season your wood for approximately 2 years?
Do you want supplemental heat from your woodstove or is it your main source of heat during the winter?
What size is the flue collar on the stove?
What size is the pipe between the stove's flue collar and the clay thimble?
Is that pipe a singe wall pipe or a double wall pipe?
Can you share a picture of the stove/pipe connected to the thimble? If not, can you describe the lengths of pipe (vertical/horizontal/sloped) and elbows used?
Do you have a budget?
Have you had or would you consider a professional chimney sweep clean and inspect your chimney?

The cracking on the exterior of the chimney may not be any concern structurally. Bricks need maintenance and cracks in the mortar can be repaired by a mason. I would recommend you find a reputable chimney sweep to come clean the chimney and do an inspection to make sure the liner and joints are intact and not degraded. While he is there ask him about the exterior cracks and ask him if he is familiar with installing insulated stainless liners in chimneys. Ask if he does free quotes for installing insulated liners.

I keep emphasizing an insulated liner because flue gas temperature is detrimental in promoting chimney draft and mitigating creosote. The insulated liner will keep the flue gas from being absorbed into the masonry and help with the creosote issue you are having. However! It will not eliminate it if you are burning wood and garbage (things you shouldn't burn).

If you have a saved photo on your computer (or phone) you can click the "Upload File" button next to "Post Reply" and attach the photo. A picture is worth a thousand words.

Welcome to the site.

 

[Marshy]

Most of the ones I have seen installed used 6" pipe. To boot many of the burners had 8" outlets. I would have concerns as well as the typical rule is to not go down in size/diameter. My folks have a Jensen indoor woodboiler with a 8" outlet and had a 6" liner installed this past fall. They burn 8-10 cord a year (everyday of the burning season), and haven't had any issues as of yet that I have heard about. I'm interested to see how dirty it is when they clean it (haven't yet this season). If it looks good, I am installing a liner myself this summer. I have a 8" outlet on a old Thermo control and a 8 x 12 flue on the outside wall like you. I have to clean mine every couple weeks or it clogs up, and that's with seasoned clean wood. The creosote I'm getting tells me it cools off before it can exit the chimney. Very similar to the pic you posted. Big flaky chunks.

Good reply. Its a general rule of thumb that the chimney and connecting pipe not be any smaller than the size of the flue collar of the appliance. However, I have heard of people having success with running a 6" insulated liner down their chimney when the stove flue collar is 8". It may work it may not, each situation is different.

They do make oval liners but in general, if you are installing an insulated liner then I recall you want no less than 1.5" of additional space over the size of the liner. So, a 6" liner would require 7.5"... The problem is, if you measured the inside of your 8x12 liner you will likely come up with around 7x11 inches of actual room. The 8x12 dimension is the outside dimensions of the liner where as the 8" dimension of a thimble is the inside dimension.

 

[sirbuildalot]

Good points Marshy,

My liner is 7x11 inside. My plan is to use a HD smooth flex liner and pour in Vermiculite for the insulation.

 

[hayboy]

Most of the ones I have seen installed used 6" pipe. To boot many of the burners had 8" outlets. I would have concerns as well as the typical rule is to not go down in size/diameter. My folks have a Jensen indoor woodboiler with a 8" outlet and had a 6" liner installed this past fall. They burn 8-10 cord a year (everyday of the burning season), and haven't had any issues as of yet that I have heard about. I'm interested to see how dirty it is when they clean it (haven't yet this season). If it looks good, I am installing a liner myself this summer. I have a 8" outlet on a old Thermo control and a 8 x 12 flue on the outside wall like you. I have to clean mine every couple weeks or it clogs up, and that's with seasoned clean wood. The creosote I'm getting tells me it cools off before it can exit the chimney. Very similar to the pic you posted. Big flaky chunks.

Sounds like me. Yes I Know what the perfect way to burn wood. After thinking about this whole thing, I told my wife we may just kiss the wood burning good bye.

 

[Marshy]

You could keep the lower part of the chimney and cleanout, install an anchor plate and convert to class A chimney up the side of the house like this....

 

[hayboy]

How in the world would you clean that, if that is 4ft. joints? YES inside is 6.75 on the narrow side, I can't see putting in a 6in liner with on 3/4 in clearance. Gave it a through cleaning today, looking for spring.

 

[sirbuildalot]

The pipe marshy suggested doesn't require a liner. It's already stainless steel pipe.

 

[MountainHigh]

I don't see what kind of stove you have but if it's an old one, it will not be very efficient, and that Chimney is on outside wall so it's natural to get lots of creosote buildup when the temps of the chimney cannot be kept high.

I second the good points already made on single wall Stainless Steel pipe liner (either flexi pipe or straight are available) as being a reasonably priced and safer solution, but you might also want to look at a newer EPA stove that gets decent secondary burn to be more efficient on a SS pipe liner. New stoves on properly sized SS pipe burn very clean as a rule.

As you've been burning for many years, you know the value of good dry wood. That is even more critical if you want to heat with a newer stove.

Check out Stainless chimney liners and see if it is cost effective for your needs.

 

[Marshy]

How in the world would you clean that, if that is 4ft. joints? YES inside is 6.75 on the narrow side, I can't see putting in a 6in liner with on 3/4 in clearance. Gave it a through cleaning today, looking for spring.

Idk what you are talking about when you say 4 foot joist... This is not my chimney, it's the neighbors up the road. It has about 2 ft of masonry chimney at ground level with a clean out door. Then it transitions into Class A chimney pipe. I have you this example because your first post was asking g if the cracks were a structurally issue. If they are and the chimney needs to be removed then this design would be helpful.

 

[hayboy]

Idk what you are talking about when you say 4 foot joist...

If that is not a one piece chimney pipe, looking at the picture it looks like about 4 ft pieces joined together, making it 7 or 8 ft above the roof. Unless he takes it apart or puts a ladder on the roof, how does he clean it. I still would like to hear someone tell their problems with installing a 6 in liner in a 6 3/4 in inside measured clay liner some 20 ft tall, I know that it was not built perfect straight, would be almost impossible. My heater is old, 33yrs min, I burn a wheelbarrow of wood in 24 hrs, if it is cold. When I bought it, I looked long and hard to find something I would not have to have my wood split to a just so so size, the door is big enough to allow maybe a 12 or 14 in dia log if the ash level is low. As they say in politics, everything is on the table for now. THANKS

 

[sirbuildalot]

Typically, those types of chimneys as shown have a tee at the bottom that acts as the cleanout. You simply sweep from the bottom up through the cleanout/tee. Very easy, and no ladders or roofs to go on. As for your liner, you could install an uninsulated 6" liner and pour vermiculite insulation around it after its installed.

 

[hayboy]

Understand that, I always cleaned from the top using 2 10ft pieces of steel conduit with a 8x12 brush, my problem is not being able to do that every couple of weeks with my physical condition as such.

 

[hayboy]

Except for thel70deg temps the middle of this week, this would last about 1 week of real cold weather.