Siding on Chimneys

[Caw]

Where I live we have a lot of very old homes (1600-1800s colonials) and many new builds try to match the colonial look so I see mostly traditional masonry chimneys. Many homes with multiples.

However lately I've been seeing more and more chimneys with siding, as in the pic below. Is this just siding on the outside of a regular masonry chimney? That would seem dangerous as it probably attaches to wood strapping. Or do these homes likely have a ZC appliance inside and there's just an insulated liner in the chimney?

Ive read conflicting things about them but I'm mostly just curious. I prefer the traditional brick look but these are definitely showing up more and more here.

 

[SpaceBus]

There is probably a class A chimney inside of a chase.

 

[faultymechanics]

Where I live we have a lot of very old homes (1600-1800s colonials) and many new builds try to match the colonial look so I see mostly traditional masonry chimneys. Many homes with multiples.

However lately I've been seeing more and more chimneys with siding, as in the pic below. Is this just siding on the outside of a regular masonry chimney? That would seem dangerous as it probably attaches to wood strapping. Or do these homes likely have a ZC appliance inside and there's just an insulated liner in the chimney?

Ive read conflicting things about them but I'm mostly just curious. I prefer the traditional brick look but these are definitely showing up more and more here.

No offense to those who have them but in my mind a chimney is some kind of stone, brick or something like that. Siding just seems bizarre. I hope that doesn't catch on too much.

 

[Caw]

I agree I think its pretty ugly but lots of people seem to like it.

Im sorry to ask a rookie question here but are there other classes of chimneys? I know class A is for venting wood m, coal, and oil burning appliances. How does a chase protect it?

 

[tabner]

I agree I think its pretty ugly but lots of people seem to like it.

Im sorry to ask a rookie question here but are there other classes of chimneys? I know class A is for venting wood m, coal, and oil burning appliances. How does a chase protect it?

I don't think the Chase protects it, it just hides it.
Some people don't like the look of a class A stainless chimney up the side of the house, so they hide it in a chase.
I think as far as new construction, it may be a lot quicker and easier to put up class A and hide it in a chase. A regular builder can put this together pretty easily. Whereas a true masonry chimney would likely require a mason and a lot more time and money.
plus it seems like most masonry chimneys end up needing to be lined anyways. Based on things I've read here, the Class A actually makes a better and safer chimney for wood burning appliances.

 

[Caw]

I think I worded my question about the chase poorly. What is preventing the chimney itself from damaging the vinyl/wood in the chase structure? I suppose there is enough clearance/insulation to protect it...hopefully. I dont know enough about this type of chimney clearly!

Side note- Mine is a traditional 24' exterior masonry chimney with a liner straight shot down to the stove that BARELY fit down. It was not easy getting that sucker down there. I didn't do it myself for this and just an abundance of caution safety reasons, had the pros out, but it took them quite a bit of maneuvering.

 

[tabner]

I think I worded my question about the chase poorly. What is preventing the chimney itself from damaging the vinyl/wood in the chase structure? I suppose there is enough clearance/insulation to protect it...hopefully. I dont know enough about this type of chimney clearly!

Side note- Mine is a traditional 24' exterior masonry chimney with a liner straight shot down to the stove that BARELY fit down. It was not easy getting that sucker down there. I didn't do it myself for this and just an abundance of caution safety reasons, had the pros out, but it took them quite a bit of maneuvering.

I believe clearance requirements on Class A chimney pipe is just 2". So the chase is just build at least 2" of air space off Class A.

 

[peakbagger]

IMHO Its a cost and speed issue. Try to find a mason that does quality work these days and you will see why the shift is being made. Good masons have more commercial work than they can handle and the only ones who advertise are the ones that contractors will not let on their site. its hard work and most masons shoulders are shot after 20 years. They can try to hire tenders but its low pay hard work and most tenders are only on the job for a short time before deciding that its not for them. On marginal soils adding an exterior masonry chimney to an existing structure is just asking for trouble. They need wide footings tied into the house footings or they will settle at different rates. If you want the stone or brick look there are various adhered systems using stone or brick facers that can give you the looks but in my experience they will need repointing and maintenance more often

Exterior masonry chimneys unless lined and insulated make starts ups harder as they are always cold. I built a block chimney myself years ago and would not do it again. I have paid twice for my masonry chimney, once to get it built and once to have all the brick removed down below the roof line and replaced. If I build another home its going to be premium insulated double wall chimney pipe in an interior chase exiting near the ridge pole. Its highly likely the section sticking out of the roof will be AZEK or some other no maintenance surface with stainless steel custom cap. It will outlive me.

 

[Caw]

I definitely agree on masonry being hard work. My grandfather was a Mason and his body was beat to heck when he was older and I knew him. They did nice work though he always drove us around town showing us the stuff he and his father built.

The brick facing is interesting. I see that on a lot of houses here too and commercially. It does look nice, but as you said im not sure of the longevity.

I didn't realize the clearance was so small for a class a chimney. It all makes sense now taking that into account + cost/time savings. I still think its ugly as sin though!

My chimney is just terracotta lined with a non insulated liner. No way an insulated one was going to fit without drilling out the masonry liner. It actually has quite good draft even on start up, but it's also in a very good location on my house/property for good draft. Works well even on 45 degree days.

There's a lot more to chimneys than a rook like me would have known.

 

[SpaceBus]

Class A chimneys usually perform better than a masonry chimney and unless you just love brick there isn't a good reason to go masonry on new construction. Peakbagger makes a good point about finding a skilled mason, especially one that will build the chimney to code. Most existing masonry chimneys need a smaller liner because most stoves call for that, especially compared to a fireplace chimney. Insulation is almost always required since nearly every masonry chimney is not installed to code. The mason who build the chimney in our house did a good job keeping clearances to code until the drywall/finishing crew got involved, they trimmed the required gaps right up to the chimney... If you really must have the brick look you can put brick veneer on just about anything. Real Masonry requires an additional footing to hold all that weight. Most fireplaces now are high efficiency and/or "zero clearance" units and there really is no point to build a giant masonry footer and structure. Some folks just can't live without a traditional masonry fireplace in their house, but then you get into all of the downsides of an open fireplace.

TL/DR: Masonry chimneys are old technology and are objectively outclassed by modern building and solid fuel appliances.

 

[Caw]

Yeah it all makes sense. Sounds like brick veneer is the future for brick lovers on new construction. That would be fine by me. Im not moving unless I win the lottery though. I did enough of that when I was younger! Its the worst.

 

[kennyp2339]

So to take this a step further, when looking at a chimney on a house when you see a masonry chimney on the outside wall it usually means the chimney was an after thought for like a fireplace, when you see the same chimney centrally located then your prob dealing with some sort of main heating whether its for a wood stove, furnace or fireplace.

 

[stoveliker]

I'm not sure; in my neighborhood all homes (late 70s, bit not a standard type as all are different) have a chimney, all brick, and all on the outside.

To me that suggests that they were built when the homes were built with these chimneys.

 

[kennyp2339]

I'm not sure; in my neighborhood all homes (late 70s, bit not a standard type as all are different) have a chimney, all brick, and all on the outside.

To me that suggests that they were built when the homes were built with these chimneys.

yup after thought as per design.

 

[peakbagger]

Not sure I would buy that. In a smaller new england homes like cape cods, an interior masonry chimney does eat up a lot of valuable space. Hanging the bulk of it outside the exterior wall eats up a lot less room. Of course it also creates a potential massive heat sink to the outdoors as the R value of brick is slim to none. My neighbors have a very dramatic natural granite fireplace/chimney located in the end wall of their home. Its surrounded with glass windows. It also sucks the heat out of the house big time. I think they had to boost up their radiators in that space after the first winter. Then again in tract subdivision its a lot easier to offer and exterior chmney. I grew up in a house that was bought by the mason working for big developer, he added a brick front facade and a combined upper and lower fireplace in the basement and the living room as wedding gift for a daughter. It was a neat house but not easy to heat. My moms roses up against that fireplace wall always bloomed a few weeks early due to the heat coming out of the house from the fireplaces.

 

[Bad LP]

So to take this a step further, when looking at a chimney on a house when you see a masonry chimney on the outside wall it usually means the chimney was an after thought for like a fireplace, when you see the same chimney centrally located then your prob dealing with some sort of main heating whether its for a wood stove, furnace or fireplace.

Re: After thought on an exterior chimney. Ahhh no.
Nothing could be further from the facts. Room layouts and personal preference determine where the fireplace goes. I don't know where you're from but chimneys need a footing and up here where the norm is a full basement the footing for it gets poured along with the same for the foundation walls.

As for center chimneys I designed my house like that for a few reasons but #1 was to avoid creosote build up in a very cold environment. I also wanted a fireplace in the living room that did get changed to an insert. I also wanted a woodstove in the basement for a more central heat source that turned into a wood boiler but my gas boiler also runs thru that huge block of concrete and field stone right off the ridge line.

Yes all that block, clay liner, stone and cement took a long time to create. I have no regrets on what I had designed and built. Probably added 30K to the overall project but I gained all sorts of flexibility on what I can burn and how.

 

[SpaceBus]

Clay liners are nice since you can use them for any fuel, but most wood burning appliances don't like them. My Morso struggles to get going on days with no breeze since it is tiny and our chimney has an 8x8 (id) clay liner. That's no fault of the chimney, it was built with a VC Defiant I in mind, but that stove was about three times too big for our tiny well insulated saltbox.

 

[Chuck the Canuck]

This conversation has been very informative for me. I love coming over to Hearth.com and browsing the various threads that people are talking about. This was a great discussion for me, and I really appreciate all of the input posted by the members.

 

[Caw]

I have a smaller New England Cape style house. Half gambrel roof, 3 beds, 2 baths, about 1700 sq feet and as I mentioned earlier I have a 24' exterior masonry chimney. It works very well as there is always a breeze and its in a good location relative to my house/property. The house is very tight and retains heat well so my little Osburn 1600 handles the entire heating load.

While I'd prefer a central chimney for even better function/more heat it would absolutely kill the design of the house. It would just take up too much space. We have a central staircase off of the main living room where the stove is and it carries the heat right up to the bedrooms without needing a fan. The rest of the middle of the house is hallway or dining room wall. I think a central stove and off in the distance staircase would actually work worse for me.

I'd say its pretty evenly dispersed here with chimneys. Newer houses (and by newer I mean like 1960 onward) I tend to see exterior chimneys. Older houses, especially the 1600-1800s colonials often have multiple chimneys, sometimes even multiple central chimneys, for reasons discussed above. But yeah anything current Id say more exterior but maybe 70/30 if I had to guess.

I grew up in a 1300 sq ft 1 floor ranch with a huge fireplace on a central wall that we used regularly to make the rest of the house freezing because we loved fires. It tool up tons of space. We also had a wood stove in the basement and an exterior chimney for that but we never used it. I looked at it recently as its still there....it's an ancient smoke dragon. Just a cast iron box. I'm almost positive if I tried to light that thing I'd burn the house down!

 

[SpaceBus]

That's the nice thing about a class A chimney, it can go anywhere and all you see is the connector pipe coming off the stove.

 

[john26]

So to take this a step further, when looking at a chimney on a house when you see a masonry chimney on the outside wall it usually means the chimney was an after thought for like a fireplace, when you see the same chimney centrally located then your prob dealing with some sort of main heating whether its for a wood stove, furnace or fireplace.

I don't agree with it being an after thought. I live in a subdivision with almost 400 homes in it built between 1979 and 2000. All of the houses have fireplaces many have 2, some of the atrium ranch houses have internal chimneys most of the 2 story and traditional ranches have them on the outer wall. They are all full masonry wood burning fireplaces many converted to gas log later. Theses houses were all originally designed and built this way. I will agree they are for aesthetics and not for intended as a heat source but they were not an after thought , like hey we can stick a fireplace here kind of thing. Many homes in the western part of St Louis county and St Charles county Missouri were built that way especially from the late 70's up untill the early 90's. Many of the spec homes in this area had zero clearance fireplaces with sided chases from mid 80's on, my parents have one.

 

[kennyp2339]

I don't agree with it being an after thought. I live in a subdivision with almost 400 homes in it built between 1979 and 2000. All of the houses have fireplaces many have 2, some of the atrium ranch houses have internal chimneys most of the 2 story and traditional ranches have them on the outer wall. They are all full masonry wood burning fireplaces many converted to gas log later. Theses houses were all originally designed and built this way. I will agree they are for aesthetics and not for intended as a heat source but they were not an after thought , like hey we can stick a fireplace here kind of thing. Many homes in the western part of St Louis county and St Charles county Missouri were built that way especially from the late 70's up untill the early 90's. Many of the spec homes in this area had zero clearance fireplaces with sided chases from mid 80's on, my parents have one.

your not going far enough back in time, the whole chimney on the outside envelope was developed post WWII cons when modern building techniques were developed and suburban building became the new norm (remember speed was the key) great examples are your levit towns in the mid-atlantic.

 

[john26]

I was referring to modern homes. I think things maybe be different here in the mid west even with the older homes I have only been around a few that date between 1830 and 1900 true log cabins the they had external stone chimneys. My guess is that was the only wat to build it with the oak log construction. Most of the homes in rural Missouri that had wood heat as a main heat source built between 1900 and and 1960 or maybe even 1970 had cinder block and clay tile a lot on external wall. Many seem to have been replaced with class A later on due to a remodel or stove relocation. Circulators were very popular around here in the rural areas and still seem to be used.

 

[bholler]

your not going far enough back in time, the whole chimney on the outside envelope was developed post WWII cons when modern building techniques were developed and suburban building became the new norm (remember speed was the key) great examples are your levit towns in the mid-atlantic.

No actually it was started long before that. They built exterior chimneys in the colonial period here out of wood larger inside with mud and clay. Many were held up by a brace that could be removed when the chimney caught on fire allowing it to fall away from the house.

Additionally nearly every summer kitchen in our area has an external chimney and many cooking fireplaces in the main house were external as well.

It is not a new concept

 

[bholler]

I was referring to modern homes. I think things maybe be different here in the mid west even with the older homes I have only been around a few that date between 1830 and 1900 true log cabins the they had external stone chimneys. My guess is that was the only wat to build it with the oak log construction. Most of the homes in rural Missouri that had wood heat as a main heat source built between 1900 and and 1960 or maybe even 1970 had cinder block and clay tile a lot on external wall. Many seem to have been replaced with class A later on due to a remodel or stove relocation. Circulators were very popular around here in the rural areas and still seem to be used.

Good point we have many cabins like that here as well. Single story log structure with a large stone chimney on one or both ends.