October 7, 2025 • 18 mins
A roaring fire feels timeless, but the way we move heat and smoke has changed dramatically—from open hearths that once filled rooms with fumes to thoughtfully engineered systems that keep warmth in and hazards out. We explore how castles got away with walk-in fireboxes, why Count Rumford’s angled design still matters, and how Benjamin Franklin’s stove reinvented efficiency by keeping more heat where you need it.
We also get practical about safety. You’ll hear why clay flue liners became a turning point, how the late adoption of refractory mortar left older chimneys vulnerable, and what today’s repair options look like—from one-piece stainless liners to in-place relining systems. We break down the hidden risks inside manufactured chases, where a small misalignment can leak heat into wood framing and quietly prime a structure fire. And we draw a hard line between chimney fires fueled by creosote and full-on house fires caused by heat escaping the flue path.
If you burn wood, the big lesson is simple: avoid “low and slow.” Smoldering fires invite creosote, and creosote can burn near 2,000°F, cracking tiles and opening pathways to nearby framing. We share real-world tips for hot, efficient burns, using stovepipe thermometers, caring for catalytic combustors, scheduling chimney sweeps, and understanding the basic anatomy of your system—firebox, damper, smoke chamber, and flue—so you can spot trouble early. Subscribe for more smart home know-how, share this with someone who loves their fireplace, and leave a review with your best fire-safety habit—we’ll feature our favorites next time.
To learn more about Habitation Investigation, the Three-time Winner of the Best Home Inspection Company in the Midwest Plus the Winner of Consumer Choice Award for Columbus Ohio visit Home Inspection Columbus Ohio - Habitation Investigation (homeinspectionsinohio.com)
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
SPEAKER_00 (00:01):
Alright, Laura.
Let's talk about fireplaces,chimneys, and kind of the parts
of them and how they developedover the years.
SPEAKER_01 (00:09):
I like history.
History is fun.
I'm a geek.
SPEAKER_00 (00:12):
Yeah, you are a history geek.
So anyway, fireplaces.
Originally in old house in olderhouses, it was I think it's like
the old Tudor style.
It was just a rectangular builtroom, and you had a fire in the
middle and a hole in the roof.
And that's how you got the smokeout.
Really old school.
SPEAKER_01 (00:33):
That does not sound healthy because I can't see the
smoke going out well.
SPEAKER_00 (00:36):
Well, that might be why the life expenses were quite
a bit shorter.
SPEAKER_01 (00:39):
That could be.
SPEAKER_00 (00:42):
So anyway, so you had that.
And then you had fireplaces,like they started using bricks
to for your firebox, and then itdirected the smoke outside,
which at one point the chimneyswere actually made out of wood,
like sticks and mud.
And they had a string.
(01:13):
You'd still have your rock, yourstone, uh base, and firebox, but
you pull down the chimney.
SPEAKER_01 (01:22):
This is sounding reminiscent of an alone series.
SPEAKER_00 (01:25):
It does, yeah, it does.
Look, I've seen several people.
SPEAKER_01 (01:27):
We've seen several people going down there.
SPEAKER_00 (01:30):
So that was that.
And then that's that's how itwas.
And the chimney were huge at thetime.
The fireboxes, you get somenicer places.
Remember when we're we're wherewere we?
SPEAKER_01 (01:39):
We were in Ireland.
What castle?
It wasn't Barney Castle, was it?
SPEAKER_00 (01:44):
We were in Barney Castle.
Right, but I don't think it hada huge fire.
SPEAKER_01 (01:48):
Like you could walk into it.
SPEAKER_00 (01:49):
You could walk, I can completely stand up in that.
But there's also the And theythey'd made it smaller.
SPEAKER_01 (01:54):
Whichever one I'm thinking of had been smaller.
Like they had started outlarger, and then like however
many hundreds of years ago, theymade it smaller, but it was
still where we could walk intoit and stand and they could
roast a whole cow in it.
SPEAKER_00 (02:08):
That was that was uh Barney Castle.
They roast a whole cow insidethat thing.
But there's another place wewent into Kylmore Abbey.
Kylmore Abbey, they had a hugeroom.
They had it was it was no justlike the I don't know what you
call the sitting room, whatever,but they had a room that had a
huge fireplace where I could notstand up in, but it was easily
(02:32):
five feet high.
I had to bend down a little bit,but it was five feet high, just
as wide, and that was theopening for the firebox.
See, that's just cool.
It's cool, but it's veryinefficient, which is why
there's a guy called CountRumsford.
Okay, he designed um his designwas the firebox was not quite so
(02:55):
deep, and it was angled, it wenta little bit narrower as it went
back and narrowed in a littlebit, and that back was angled.
And what that did, that helpedimprove uh heat reflecting back
into the house.
Okay, also a bit more efficientas far as airflow.
Because old, like even now, likeopen fireplaces, you don't have
(03:18):
the glass doors, a lot of yourair just gets sucked straight up
and out through the chimney.
And because you got all thatcombustion going on, the
replacement air for that stuffthat's getting sucked out, it
has to be has to come in throughother areas of the house, such
as your cracks in your windows,doors.
If you have a crawl space, it'sprobably sucking up some of that
(03:41):
musty air from the crawl space,sucking that up.
So Rumsford style fireplace weremore efficient.
But then you got Ben Franklin.
Ben Franklin.
Ben Franklin was like 18, like17, something like that.
He made the Franklin stove,which is the pot belly stove.
(04:05):
Yep, and those were fantastic,and and he was such an awesome
dude.
He he he liked plumbing, whichis unique back then, but he had
he liked indoor plumbing, but hedid not he did not want to
patent that that stove.
He said it's free for everybody,anybody to use that design
because it's it's cut down awood, it greatly reduced air
(04:28):
loss, right?
And it greatly, you know, helpedhelp people stay warm.
So that that was awesome bythat.
SPEAKER_01 (04:33):
That is very cool.
SPEAKER_00 (04:34):
But as as time went on, they you know they they get
they did better, but up until1890, chimneys did not have a uh
flue liner on the inside, it wasjust like brick or stone and
mortar going all the way up.
So around 1890, they said, hey,we should do a flue liner to
(04:59):
help this thing draft to draftbetter.
So that happened.
Like our house, our previoushouse built in 1883 at the
newest, there's it was anunlined chimney.
Right.
SPEAKER_01 (05:10):
Because we were the ones that ended up getting it
lined.
SPEAKER_00 (05:12):
Yes, it makes it makes sense.
Like we put down a stainlesssteel line pipe through there
for the wood stove, right?
And that made it a lot moreefficient and and safe to use
because our that was not safe touse without a liner through
there.
SPEAKER_01 (05:25):
Wasn't there also a difference in the mortar that
they used?
Like at a certain point, theyswitched to one that was more
heat resistant.
SPEAKER_00 (05:32):
Yes, yep, good point.
So refractory mortar, refractorymortar can't handle the heat,
the high heat.
They didn't start usingrefractory mortar until 1990.
Holy crap.
Which makes no sense to me thatwould take this long to go, you
know what?
I wonder if this heat is makingthis mortar fall apart.
SPEAKER_01 (05:54):
So, like, how long did they know about refractory
mortar?
Like, how long had it beeninvented before they decided to
use it in chimneys?
SPEAKER_00 (06:02):
That I don't know.
SPEAKER_01 (06:03):
They probably That might be an interesting
question.
SPEAKER_00 (06:05):
Like, well, it's not getting that hot inside that
chimney because of all theairflow.
But once they put in the flues,okay, now it's a line harder
line.
Now that all the heat is goingthrough a little narrower space,
and they probably like, oh, thatstuff is now hot, deteriorating.
Yeah, it's hotter deteriorating,so we need to switch that up.
So yeah, 1990s is pretty muchwhen they started requiring
(06:30):
refractory mortar, and that'snot hearing we we can't as a
home inspector.
We we don't know.
Is it refractory mortar?
I don't know.
But if it's after if it's before1990, probably not.
SPEAKER_01 (06:40):
Probably not, which means then if it's before 1990
and it doesn't have a liner in,it probably should.
Well, it it yeah, like uhautomatically because you don't
have the appropriate mortar init.
Or could they line it, likecould they do that little
squeegee thing and redo thatwith refractory mortar?
SPEAKER_00 (07:01):
Yes.
SPEAKER_01 (07:01):
Okay, yes, yeah.
SPEAKER_00 (07:03):
There are ways to repair chimneys.
Like uh, say you you got secondone mortars gone in the middle
of the chimney.
There's no way you can reachdown and repair that.
There are ways they can uh forcemore new mortar into those
cracks and and basicallybasically skim coat the entire
interior of the chimney.
(07:24):
So that would be worth it.
So that's that it could it canbe done.
SPEAKER_01 (07:27):
I don't know.
I I liked the stainless steelliner, like it was all one piece
that we put in, so there wasn'tany potential for it separating
or anything like that.
SPEAKER_00 (07:36):
Well, there there is.
SPEAKER_01 (07:38):
And we just we didn't have to worry about it,
it was in and done.
SPEAKER_00 (07:41):
Correct.
Ours was a single piece.
Yeah, you need to get thoselooked at as well because I have
seen metal sections of the pipeswhere they never really line
them up.
So you're I'm here, I'm doingthe chimney scope, going there's
a gas fireplace, follow thatchimney with a camera.
(08:01):
All of a sudden the pipes do notline up.
There's an offset where theydon't line up perfectly, one
just off to the side a littlebit, which means there's a gap
where the heat coming up thatpipe all of a sudden goes
outside of that pipe.
And if it's a modern house withlike a like a wooden, like a
manufactured insert, like woodburning insert, like the new
(08:25):
house, it's just it's justmetal, maybe refractor panel in
the background behind thefirebox.
Those chimneys, they look likethe same as the house, the same
vinyl siding they to put on.
Well, outside that metal pipe,that chimney is just it's wooden
frame.
It's wooden frame.
(08:45):
They built just like the house.
You got your wooden frame, thesheathing, the house wrap, and
then the siding.
SPEAKER_01 (08:51):
So that's gonna start causing pyrolization of
that wood behind that area then.
Correct.
SPEAKER_00 (08:57):
You get enough heat coming out through the through
that gap, the whole inside ofthat can heat up and then
eventually catch fire.
It all depends on how big a fireyou have going on.
If it's gas, probably a littleless likely.
But I've seen those manufacturedum inserts, they they burn, they
can burn wood some wood some ofthem, and you you get some
sparks flying up there insideyour area that you have charred
(09:19):
over the last or the previousowner charred for the last 10,
15, 10 years.
SPEAKER_02 (09:24):
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(09:45):
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SPEAKER_00 (09:51):
You're you're you're gonna have a chimney fire.
Didn't you it's really more of astructure fire at that point
because it's not it's not thecreosote burning.
SPEAKER_01 (09:58):
It's it's the house.
SPEAKER_00 (09:59):
It's that it's the wooden structure around that
chimney.
Yeah, that's a house, that's ahouse fire.
SPEAKER_01 (10:03):
Didn't you say that you would talk to a guy that
that put in those um thoseliners and like the the ones
that got pieced together, andthey didn't scope them
afterwards, they just pusheddown until they heard it click.
So you don't know if it'sclicking correctly or what, but
they just keep building on that,and then they never look to make
sure that it was all done right.
SPEAKER_00 (10:24):
Yeah, so they would yeah, so they they'd have to
have some of a I can't imaginejust dropping the top one down,
but they would connect them andlower them down and then push
them to make sure they'rethey're connected, but that's
doesn't it doesn't work.
I've seen uh metal liner where acouple sections had offsets in
(10:46):
them, which each offset is anopportunity for the heat and
sparks to escape and go aroundto the structure outside of that
flue.
So definitely not not a safething.
There are there's not real goodstats, less than mine knew,
regarding house fires that werecaused by the chimney.
Mine growing up because youryours didn't.
SPEAKER_01 (11:07):
Well we we had a wood stove.
SPEAKER_00 (11:09):
Okay, so you was your fire inside the the flu?
SPEAKER_01 (11:13):
I believe what they said was that where it joined
the ceiling, that that partthere.
The thimble the okay, somethinghad separated there and it had
caused over time pyrolization ofthat wood.
Now that I know what that is, Ididn't at the time, and it just
spread across the attic at thatpoint.
SPEAKER_00 (11:34):
So you your at your pipe there may have been
disconnected for a long time,and it just finally got hot
enough to do you know to catchfire.
But last time you there's somethere wasn't real good stats.
Okay, so you got chimney fireand you got a house fire.
Chimney fire, this is whereyou're talking about the
creosote building up.
SPEAKER_01 (11:56):
Okay.
SPEAKER_00 (11:56):
Creosote is it's like unburned wood particles,
basically.
It's unburnt uh particles fromthe smoke.
And I this how I it may not beexactly correct.
I think of creosote as kind ofcondensed, it's a condensation
of the smoke along the sides.
SPEAKER_01 (12:15):
Okay, that's kind of where I was yeah.
SPEAKER_00 (12:18):
So eventually that stuff it is flammable, and I
just looked something up.
That stuff can burn like 2,000degrees, the creosote when it
burns.
SPEAKER_01 (12:26):
Well, and that's what the chimney sweep is
supposed to come in and get ridof.
SPEAKER_00 (12:29):
Yes, chimney, when you have a higher chimney sweep,
they can take a look, and thenthey could have like special
brushes, vacuums, or they'redoing that to knock down all
that that creosote, at least thebuildup of there's this flus are
never gonna be clean.
Right.
Clean up the eat off of afterafter after you start using
them.
But they they take down all thatcreosote because that creosote
(12:51):
buildup, that is that by itselfis a fire hazard.
And if it catches fire, it gets,like I said, 2,000 degrees, it
will crack your tiles.
And it will damage your chimney.
Correct, yes.
SPEAKER_01 (13:02):
Now, I remember you getting a thermostat for our
because when at our old house weused to have a wood-burning
stove.
So I remember we had athermostat on that because you
like to keep it burning at acertain temperature to lower the
amount of creosote that was in.
(13:22):
Oh, yes, yes.
So explain that to people.
SPEAKER_00 (13:24):
All right, so since creosote is the condensation of
the smoke, if you burn it, andthis is what happened, this is
popular for like uh wood stoves.
People do this.
They don't have to start thefire all over the next morning.
So they put the fire there andthey keep the dampers kind of
closed, give it just enough airso it stays lit, barely lit, the
(13:48):
coal's going, and what you haveit give a really low, slow
burning fire.
Well, it's not that hot, so it'seasier for uh the smoke to hit,
I'll call it dew point, where itwill start condensing.
Just like moisture in the air,how it condenses like a cold can
of soda, the moisture in the airwill condense and get the
(14:10):
outside wet.
Because of condensation.
So if it's if the fire's burninglow and slow, you're gonna hit
that condensation point for thatsmoke easily.
Plus, you don't have that muchair going through, which makes
this allows the smoke just tolinger and adhere easier.
(14:32):
And adhere.
So you so you need to haveyou're supposed to have your
fireplace, like the wood stovepipe.
I think it was like 250 to 370around around that.
I I keep seeing differentnumbers.
I I so I I think there needs tobe better research on that, but
you do not burn it low and slow.
(14:53):
You burn it nice and hot.
You don't want to if you have awood stove, you don't want to
your stove glowing red.
You're probably over over.
SPEAKER_01 (15:02):
And you're melting it and you're damaging it.
SPEAKER_00 (15:04):
You're over firing that.
Well, if you have a catalytic umcatalycome converter, is that
what you're doing?
Yeah.
It is basically the same thing.
But anyway, there's stuff inthere.
Some of them will have uhplatinum in like a little waffle
thing that allows the combustionto happen at a lower
temperature.
SPEAKER_01 (15:23):
Okay.
SPEAKER_00 (15:23):
And that will help us burn the smoke.
But but those go out, like thosedon't yeah, those need to be
replaced every now and then.
Or if you burn a wood that had apiece that had a nail in it,
you're gonna destroy that thatthing automatically.
So no nails in your wood.
Correct, correct.
Depending on what you'reburning.
But you don't you gotta have ita nice hot fire.
(15:44):
That way you're not likely toare gonna have that that uh
smoke form creosote.
And if it's hot, burning hot,you probably got pretty good
airflow.
You almost have to have thatmuch oxygen for it to burn nice
and hot.
You're getting the smoke.
If there's any smoke at all,getting it go straight up and
out.
Because we would burn that ourwood stove hot, efficient.
(16:06):
You let it burn, then you let gogo all the way down, then you
fire it up nice and hot again.
You would do that, and when itwas going, there was no smoke
coming out.
No, because it was a very hot,efficient burn, just like the
fireplace we have now.
Well, the fireplace we have nowis also a different design, it's
a different design, but it'sit's designed to burn hot, very
(16:28):
like unrestricted airflow onthis thing when you burn it.
But it's totally different type,it has lots of mass to absorb
heat, so it's it's masonryheater.
Maybe we'll talk about thosesome other time.
SPEAKER_01 (16:40):
Yeah, let's do that some other time.
SPEAKER_00 (16:42):
But you do not burn your wood low and slow.
That's how you become get a firehazard with all the Creso
buildup.
But you can a Creso, like Isaid, 2,000 degrees or higher,
that will damage your mortar,crack your tiles.
If you got little gaps in yourin your flue, you're you're
(17:05):
you're really risking catchingyour structure around there on
fire.
SPEAKER_01 (17:08):
And you don't want to do that.
Trust me, as someone who livedthrough that as a kid, you don't
want that.
SPEAKER_00 (17:13):
Yep.
So I think that's about it onthis one.
So oh I think we about allright, so structure of a
fireplace.
We have a class.
So if you're a real estateagent, we get we'll teach a
class on this, but you got yourfirebox, we put your wood.
Above that's the damper, whichopens and closes, whether or not
you allow air to go up and outthrough the chimney.
Right above the damper, it'scalled the smoke chamber.
(17:36):
And what that does, it allows itkind of blocks wind from coming
down and blowing the smoke fromyour fireplace into your house.
That's a good thing.
It helps with that because theangle of the damper, and there's
a shelf there to catch debris.
But anyway, so you go firebox,damper, smoke chamber where it
angles up into your flue andthen it goes up and out.
SPEAKER_01 (17:57):
That's the design of modern fireplace.
SPEAKER_00 (18:01):
Of modern fireplace.
Yep.
SPEAKER_01 (18:04):
Well, if anybody wants a uh chimney fireplace
class, let us know.
SPEAKER_00 (18:09):
Yeah, well, yeah, we can come to your office, do one
if you want.
Or we can just do it over.
If you're a home buyer, a homeseller, or a homeowner, have us
do a chimney scope so you don'truin your your your winter by
burning your house down andkilling your family.
I mean that would be that's thetragedy.
Fortunately, people dying fromuh um house fires has gone
(18:31):
greatly has gone greatly down.
That's all because primarily allbecause of smoke detectors.
SPEAKER_01 (18:38):
Right.
SPEAKER_00 (18:39):
That is the main way that people are staying safe
from fires and not dyinganymore.
So all right, everybody.
Thank you.
Bye bye.
Alright, Laura.
Let's talk about fireplaces,chimneys, and kind of the parts
of them and how they developedover the years.
SPEAKER_01 (00:09):
I like history.
History is fun.
I'm a geek.
SPEAKER_00 (00:12):
Yeah, you are a history geek.
So anyway, fireplaces.
Originally in old house in olderhouses, it was I think it's like
the old Tudor style.
It was just a rectangular builtroom, and you had a fire in the
middle and a hole in the roof.
And that's how you got the smokeout.
Really old school.
SPEAKER_01 (00:33):
That does not sound healthy because I can't see the
smoke going out well.
SPEAKER_00 (00:36):
Well, that might be why the life expenses were quite
a bit shorter.
SPEAKER_01 (00:39):
That could be.
SPEAKER_00 (00:42):
So anyway, so you had that.
And then you had fireplaces,like they started using bricks
to for your firebox, and then itdirected the smoke outside,
which at one point the chimneyswere actually made out of wood,
like sticks and mud.
And they had a string.
(01:13):
You'd still have your rock, yourstone, uh base, and firebox, but
you pull down the chimney.
SPEAKER_01 (01:22):
This is sounding reminiscent of an alone series.
SPEAKER_00 (01:25):
It does, yeah, it does.
Look, I've seen several people.
SPEAKER_01 (01:27):
We've seen several people going down there.
SPEAKER_00 (01:30):
So that was that.
And then that's that's how itwas.
And the chimney were huge at thetime.
The fireboxes, you get somenicer places.
Remember when we're we're wherewere we?
SPEAKER_01 (01:39):
We were in Ireland.
What castle?
It wasn't Barney Castle, was it?
SPEAKER_00 (01:44):
We were in Barney Castle.
Right, but I don't think it hada huge fire.
SPEAKER_01 (01:48):
Like you could walk into it.
SPEAKER_00 (01:49):
You could walk, I can completely stand up in that.
But there's also the And theythey'd made it smaller.
SPEAKER_01 (01:54):
Whichever one I'm thinking of had been smaller.
Like they had started outlarger, and then like however
many hundreds of years ago, theymade it smaller, but it was
still where we could walk intoit and stand and they could
roast a whole cow in it.
SPEAKER_00 (02:08):
That was that was uh Barney Castle.
They roast a whole cow insidethat thing.
But there's another place wewent into Kylmore Abbey.
Kylmore Abbey, they had a hugeroom.
They had it was it was no justlike the I don't know what you
call the sitting room, whatever,but they had a room that had a
huge fireplace where I could notstand up in, but it was easily
(02:32):
five feet high.
I had to bend down a little bit,but it was five feet high, just
as wide, and that was theopening for the firebox.
See, that's just cool.
It's cool, but it's veryinefficient, which is why
there's a guy called CountRumsford.
Okay, he designed um his designwas the firebox was not quite so
(02:55):
deep, and it was angled, it wenta little bit narrower as it went
back and narrowed in a littlebit, and that back was angled.
And what that did, that helpedimprove uh heat reflecting back
into the house.
Okay, also a bit more efficientas far as airflow.
Because old, like even now, likeopen fireplaces, you don't have
(03:18):
the glass doors, a lot of yourair just gets sucked straight up
and out through the chimney.
And because you got all thatcombustion going on, the
replacement air for that stuffthat's getting sucked out, it
has to be has to come in throughother areas of the house, such
as your cracks in your windows,doors.
If you have a crawl space, it'sprobably sucking up some of that
(03:41):
musty air from the crawl space,sucking that up.
So Rumsford style fireplace weremore efficient.
But then you got Ben Franklin.
Ben Franklin.
Ben Franklin was like 18, like17, something like that.
He made the Franklin stove,which is the pot belly stove.
(04:05):
Yep, and those were fantastic,and and he was such an awesome
dude.
He he he liked plumbing, whichis unique back then, but he had
he liked indoor plumbing, but hedid not he did not want to
patent that that stove.
He said it's free for everybody,anybody to use that design
because it's it's cut down awood, it greatly reduced air
(04:28):
loss, right?
And it greatly, you know, helpedhelp people stay warm.
So that that was awesome bythat.
SPEAKER_01 (04:33):
That is very cool.
SPEAKER_00 (04:34):
But as as time went on, they you know they they get
they did better, but up until1890, chimneys did not have a uh
flue liner on the inside, it wasjust like brick or stone and
mortar going all the way up.
So around 1890, they said, hey,we should do a flue liner to
(04:59):
help this thing draft to draftbetter.
So that happened.
Like our house, our previoushouse built in 1883 at the
newest, there's it was anunlined chimney.
Right.
SPEAKER_01 (05:10):
Because we were the ones that ended up getting it
lined.
SPEAKER_00 (05:12):
Yes, it makes it makes sense.
Like we put down a stainlesssteel line pipe through there
for the wood stove, right?
And that made it a lot moreefficient and and safe to use
because our that was not safe touse without a liner through
there.
SPEAKER_01 (05:25):
Wasn't there also a difference in the mortar that
they used?
Like at a certain point, theyswitched to one that was more
heat resistant.
SPEAKER_00 (05:32):
Yes, yep, good point.
So refractory mortar, refractorymortar can't handle the heat,
the high heat.
They didn't start usingrefractory mortar until 1990.
Holy crap.
Which makes no sense to me thatwould take this long to go, you
know what?
I wonder if this heat is makingthis mortar fall apart.
SPEAKER_01 (05:54):
So, like, how long did they know about refractory
mortar?
Like, how long had it beeninvented before they decided to
use it in chimneys?
SPEAKER_00 (06:02):
That I don't know.
SPEAKER_01 (06:03):
They probably That might be an interesting
question.
SPEAKER_00 (06:05):
Like, well, it's not getting that hot inside that
chimney because of all theairflow.
But once they put in the flues,okay, now it's a line harder
line.
Now that all the heat is goingthrough a little narrower space,
and they probably like, oh, thatstuff is now hot, deteriorating.
Yeah, it's hotter deteriorating,so we need to switch that up.
So yeah, 1990s is pretty muchwhen they started requiring
(06:30):
refractory mortar, and that'snot hearing we we can't as a
home inspector.
We we don't know.
Is it refractory mortar?
I don't know.
But if it's after if it's before1990, probably not.
SPEAKER_01 (06:40):
Probably not, which means then if it's before 1990
and it doesn't have a liner in,it probably should.
Well, it it yeah, like uhautomatically because you don't
have the appropriate mortar init.
Or could they line it, likecould they do that little
squeegee thing and redo thatwith refractory mortar?
SPEAKER_00 (07:01):
Yes.
SPEAKER_01 (07:01):
Okay, yes, yeah.
SPEAKER_00 (07:03):
There are ways to repair chimneys.
Like uh, say you you got secondone mortars gone in the middle
of the chimney.
There's no way you can reachdown and repair that.
There are ways they can uh forcemore new mortar into those
cracks and and basicallybasically skim coat the entire
interior of the chimney.
(07:24):
So that would be worth it.
So that's that it could it canbe done.
SPEAKER_01 (07:27):
I don't know.
I I liked the stainless steelliner, like it was all one piece
that we put in, so there wasn'tany potential for it separating
or anything like that.
SPEAKER_00 (07:36):
Well, there there is.
SPEAKER_01 (07:38):
And we just we didn't have to worry about it,
it was in and done.
SPEAKER_00 (07:41):
Correct.
Ours was a single piece.
Yeah, you need to get thoselooked at as well because I have
seen metal sections of the pipeswhere they never really line
them up.
So you're I'm here, I'm doingthe chimney scope, going there's
a gas fireplace, follow thatchimney with a camera.
(08:01):
All of a sudden the pipes do notline up.
There's an offset where theydon't line up perfectly, one
just off to the side a littlebit, which means there's a gap
where the heat coming up thatpipe all of a sudden goes
outside of that pipe.
And if it's a modern house withlike a like a wooden, like a
manufactured insert, like woodburning insert, like the new
(08:25):
house, it's just it's justmetal, maybe refractor panel in
the background behind thefirebox.
Those chimneys, they look likethe same as the house, the same
vinyl siding they to put on.
Well, outside that metal pipe,that chimney is just it's wooden
frame.
It's wooden frame.
(08:45):
They built just like the house.
You got your wooden frame, thesheathing, the house wrap, and
then the siding.
SPEAKER_01 (08:51):
So that's gonna start causing pyrolization of
that wood behind that area then.
Correct.
SPEAKER_00 (08:57):
You get enough heat coming out through the through
that gap, the whole inside ofthat can heat up and then
eventually catch fire.
It all depends on how big a fireyou have going on.
If it's gas, probably a littleless likely.
But I've seen those manufacturedum inserts, they they burn, they
can burn wood some wood some ofthem, and you you get some
sparks flying up there insideyour area that you have charred
(09:19):
over the last or the previousowner charred for the last 10,
15, 10 years.
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(09:45):
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SPEAKER_00 (09:51):
You're you're you're gonna have a chimney fire.
Didn't you it's really more of astructure fire at that point
because it's not it's not thecreosote burning.
SPEAKER_01 (09:58):
It's it's the house.
SPEAKER_00 (09:59):
It's that it's the wooden structure around that
chimney.
Yeah, that's a house, that's ahouse fire.
SPEAKER_01 (10:03):
Didn't you say that you would talk to a guy that
that put in those um thoseliners and like the the ones
that got pieced together, andthey didn't scope them
afterwards, they just pusheddown until they heard it click.
So you don't know if it'sclicking correctly or what, but
they just keep building on that,and then they never look to make
sure that it was all done right.
SPEAKER_00 (10:24):
Yeah, so they would yeah, so they they'd have to
have some of a I can't imaginejust dropping the top one down,
but they would connect them andlower them down and then push
them to make sure they'rethey're connected, but that's
doesn't it doesn't work.
I've seen uh metal liner where acouple sections had offsets in
(10:46):
them, which each offset is anopportunity for the heat and
sparks to escape and go aroundto the structure outside of that
flue.
So definitely not not a safething.
There are there's not real goodstats, less than mine knew,
regarding house fires that werecaused by the chimney.
Mine growing up because youryours didn't.
SPEAKER_01 (11:07):
Well we we had a wood stove.
SPEAKER_00 (11:09):
Okay, so you was your fire inside the the flu?
SPEAKER_01 (11:13):
I believe what they said was that where it joined
the ceiling, that that partthere.
The thimble the okay, somethinghad separated there and it had
caused over time pyrolization ofthat wood.
Now that I know what that is, Ididn't at the time, and it just
spread across the attic at thatpoint.
SPEAKER_00 (11:34):
So you your at your pipe there may have been
disconnected for a long time,and it just finally got hot
enough to do you know to catchfire.
But last time you there's somethere wasn't real good stats.
Okay, so you got chimney fireand you got a house fire.
Chimney fire, this is whereyou're talking about the
creosote building up.
SPEAKER_01 (11:56):
Okay.
SPEAKER_00 (11:56):
Creosote is it's like unburned wood particles,
basically.
It's unburnt uh particles fromthe smoke.
And I this how I it may not beexactly correct.
I think of creosote as kind ofcondensed, it's a condensation
of the smoke along the sides.
SPEAKER_01 (12:15):
Okay, that's kind of where I was yeah.
SPEAKER_00 (12:18):
So eventually that stuff it is flammable, and I
just looked something up.
That stuff can burn like 2,000degrees, the creosote when it
burns.
SPEAKER_01 (12:26):
Well, and that's what the chimney sweep is
supposed to come in and get ridof.
SPEAKER_00 (12:29):
Yes, chimney, when you have a higher chimney sweep,
they can take a look, and thenthey could have like special
brushes, vacuums, or they'redoing that to knock down all
that that creosote, at least thebuildup of there's this flus are
never gonna be clean.
Right.
Clean up the eat off of afterafter after you start using
them.
But they they take down all thatcreosote because that creosote
(12:51):
buildup, that is that by itselfis a fire hazard.
And if it catches fire, it gets,like I said, 2,000 degrees, it
will crack your tiles.
And it will damage your chimney.
Correct, yes.
SPEAKER_01 (13:02):
Now, I remember you getting a thermostat for our
because when at our old house weused to have a wood-burning
stove.
So I remember we had athermostat on that because you
like to keep it burning at acertain temperature to lower the
amount of creosote that was in.
(13:22):
Oh, yes, yes.
So explain that to people.
SPEAKER_00 (13:24):
All right, so since creosote is the condensation of
the smoke, if you burn it, andthis is what happened, this is
popular for like uh wood stoves.
People do this.
They don't have to start thefire all over the next morning.
So they put the fire there andthey keep the dampers kind of
closed, give it just enough airso it stays lit, barely lit, the
(13:48):
coal's going, and what you haveit give a really low, slow
burning fire.
Well, it's not that hot, so it'seasier for uh the smoke to hit,
I'll call it dew point, where itwill start condensing.
Just like moisture in the air,how it condenses like a cold can
of soda, the moisture in the airwill condense and get the
(14:10):
outside wet.
Because of condensation.
So if it's if the fire's burninglow and slow, you're gonna hit
that condensation point for thatsmoke easily.
Plus, you don't have that muchair going through, which makes
this allows the smoke just tolinger and adhere easier.
(14:32):
And adhere.
So you so you need to haveyou're supposed to have your
fireplace, like the wood stovepipe.
I think it was like 250 to 370around around that.
I I keep seeing differentnumbers.
I I so I I think there needs tobe better research on that, but
you do not burn it low and slow.
(14:53):
You burn it nice and hot.
You don't want to if you have awood stove, you don't want to
your stove glowing red.
You're probably over over.
SPEAKER_01 (15:02):
And you're melting it and you're damaging it.
SPEAKER_00 (15:04):
You're over firing that.
Well, if you have a catalytic umcatalycome converter, is that
what you're doing?
Yeah.
It is basically the same thing.
But anyway, there's stuff inthere.
Some of them will have uhplatinum in like a little waffle
thing that allows the combustionto happen at a lower
temperature.
SPEAKER_01 (15:23):
Okay.
SPEAKER_00 (15:23):
And that will help us burn the smoke.
But but those go out, like thosedon't yeah, those need to be
replaced every now and then.
Or if you burn a wood that had apiece that had a nail in it,
you're gonna destroy that thatthing automatically.
So no nails in your wood.
Correct, correct.
Depending on what you'reburning.
But you don't you gotta have ita nice hot fire.
(15:44):
That way you're not likely toare gonna have that that uh
smoke form creosote.
And if it's hot, burning hot,you probably got pretty good
airflow.
You almost have to have thatmuch oxygen for it to burn nice
and hot.
You're getting the smoke.
If there's any smoke at all,getting it go straight up and
out.
Because we would burn that ourwood stove hot, efficient.
(16:06):
You let it burn, then you let gogo all the way down, then you
fire it up nice and hot again.
You would do that, and when itwas going, there was no smoke
coming out.
No, because it was a very hot,efficient burn, just like the
fireplace we have now.
Well, the fireplace we have nowis also a different design, it's
a different design, but it'sit's designed to burn hot, very
(16:28):
like unrestricted airflow onthis thing when you burn it.
But it's totally different type,it has lots of mass to absorb
heat, so it's it's masonryheater.
Maybe we'll talk about thosesome other time.
SPEAKER_01 (16:40):
Yeah, let's do that some other time.
SPEAKER_00 (16:42):
But you do not burn your wood low and slow.
That's how you become get a firehazard with all the Creso
buildup.
But you can a Creso, like Isaid, 2,000 degrees or higher,
that will damage your mortar,crack your tiles.
If you got little gaps in yourin your flue, you're you're
(17:05):
you're really risking catchingyour structure around there on
fire.
SPEAKER_01 (17:08):
And you don't want to do that.
Trust me, as someone who livedthrough that as a kid, you don't
want that.
SPEAKER_00 (17:13):
Yep.
So I think that's about it onthis one.
So oh I think we about allright, so structure of a
fireplace.
We have a class.
So if you're a real estateagent, we get we'll teach a
class on this, but you got yourfirebox, we put your wood.
Above that's the damper, whichopens and closes, whether or not
you allow air to go up and outthrough the chimney.
Right above the damper, it'scalled the smoke chamber.
(17:36):
And what that does, it allows itkind of blocks wind from coming
down and blowing the smoke fromyour fireplace into your house.
That's a good thing.
It helps with that because theangle of the damper, and there's
a shelf there to catch debris.
But anyway, so you go firebox,damper, smoke chamber where it
angles up into your flue andthen it goes up and out.
SPEAKER_01 (17:57):
That's the design of modern fireplace.
SPEAKER_00 (18:01):
Of modern fireplace.
Yep.
SPEAKER_01 (18:04):
Well, if anybody wants a uh chimney fireplace
class, let us know.
SPEAKER_00 (18:09):
Yeah, well, yeah, we can come to your office, do one
if you want.
Or we can just do it over.
If you're a home buyer, a homeseller, or a homeowner, have us
do a chimney scope so you don'truin your your your winter by
burning your house down andkilling your family.
I mean that would be that's thetragedy.
Fortunately, people dying fromuh um house fires has gone
(18:31):
greatly has gone greatly down.
That's all because primarily allbecause of smoke detectors.
SPEAKER_01 (18:38):
Right.
SPEAKER_00 (18:39):
That is the main way that people are staying safe
from fires and not dyinganymore.
So all right, everybody.
Thank you.
Bye bye.
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