Chimney height & horizontal clearance specification questions & answers:

These questions & answers help clarify the required height or other clearance distances for chimneys.

This article series describes the height requirements for chimneys, including rooftop clearances and overall chimney height necessary for proper chimney draft and function and for fire safety.

We describe what can go wrong with chimneys that are not built to proper height or with proper clearances from other building features, including improper or unsafe heating appliance or fireplace or woodstove operation, odors, soot, draft issues, etc.

FAQs About Outdoor Chimney Height & Clearance Codes & Specifications

These questions about chimney or flue height & clearance from various building features were posted originally

at CHIMNEY HEIGHT & CLEARANCE CODE - please remember to check out the details given there.

[Click to enlarge any image]

On 2021-01-14 - by (mod) -

Ben:

What a rat's nest of a problem, though a common one.

I'm sorry to say that I can't answer the legal question, that's one for you to discuss with your attorney. But I agree with you that your neighbors construction has raised safety and fire issues for all of the building occupants.

You might want to check with your local building department to find out if the proper permits and inspections were obtained.

On 2021-01-14 by Ben

I live in a rowhouse in Philadelphia. I share a party wall with my neighbor.

That wall also has my three wood burner fireplaces in it. My neighbor (same house just mirrored) had the same until he removed his fireplaces to "modernize" his house with flat walls.

We share the chimney with the neighbor.and both our flues ran up them until he removed his. He now built a roof deck on his roof that butts up to my/our chimney. Now my fireplace cap is 2.5 feet below his roof deck structure and only inches away on two sides. T

o comply with Philly code, i assume this chimney would need to be raised 2 feet over his new roof deck. My question is, who pays for the chimney to be raised? Why should I need to pay if he caused the obstruction? Any help/guidance will be appreciated.

On 2020-05-13 - by (mod) -

Saul

Forgive me for being a pain on this but "grandfathered" or not, if a chimney needs repairs, it ought to be repaired - as we don't want to burn down the building nor kill its occupants.

Generally if the chimney already meets the above-roof level criteria found in the article above then the repair may not need to extend the chimney height - though some sites with wind or other conditions may still need a taller chimney to work properly.

On 2020-05-13 20:41:46.792058 by saul

if chimney on a 50 year old house is only 2 ft above roof line, and needs repairs, is it grandfathered?

On 2020-01-26 - by (mod) -

Mic

There's a good chance this reply is incomplete as I can't see your situation, but in general

- the pellet stove chimney needs to meet fire clearances from combustibles (varies by chimney material and rating)

- the chimney has to vent above the occupied space (which is your question) sufficient to not annoy occupants - I haven't found code on
this but figure it's 10-12 ft. above deck surface PLUS

- at least 2 feet above any roof surface that would be touched at the end of a 10 ft. horizontal line drawn from the top of the chimney outlet

On 2020-01-26 by mic mcguinness

I have put an observation deck on a roof right next to an unused 8 " round flu in stone masonry, Now I want to use this 8" flu to vent
a pellet stove. Presently the chimney ends at deck level. How far up do I need to go above the deck if this is possible?

On 2019-11-07 - by (mod) -

Darrel

Reasons to fix a too-short chimney:

I can't say what action your local building authority might take if you refuse or choose not to comply, but


1. The reason for the two-foot guideline is safety, not just draft. Putting the chimney top opening at least 2 ft. above the ridge reduces the chance of a spark or ember or heat coming out of the chimney and setting the roof and the building on fire.

2. Repair is not a significant expense; it can't be more than $100. for a 6" diameter insulated metal chimney 12" length for a chimneyt height extension + even another $200. in labor if your roof is tall, steep, hard to access; of course you want to buy the same product as your present chimney so that the parts simply snap together.

3. In my experience if you are ever selling your home there are reasons why you don't want 10 inches of chimney to cause a stumble or hiccup in the sale: it's unsafe, and it telegraphs to the buyer that your home may not comply on other issues they haven't discovered - thus making them nervous

4. You might enjoy improved relations with your neighbour by raising your chimney height in response to their complaint, along with *thanking* the neighbor for calling to your attention that your home wasn't as fire-safe as it might be.

(Frankly I doubt that adding that 10" is going to change an odor complaint one bit but it might make complaining less likely as you've responded.)

On 2019-11-05 by Darrel

I have had my metal chimney on my home for 5 years and have never had any issues with drafting. My neighbor had complained that he smells smoke. So he had an inspector look at it. He found it to be a code violation because I am 10" short of the 2' above ridge line requirement. Can I get a fine if I don't fix it? And do I have to fix it? Is code only in effect when I am selling? What does my neighbor really care. It won't effect him smelling or not smelling smoke,

On 2018-12-07 - by (mod) -

Sorry Darin - what's the question?

There's not a single chimney height requirement: for example there are clearances from walls, windows, roofs.

And there may be site specific needs such as hills or trees that require a higher chimney than minimum.

Generally a chimney that's more than 10 ft. from a building might still need to be taller than the building roof to avoid downdraft problems from the nearby structure.

On 2018-10-14 by Darin

Outdoor firplace chiminey hight requirement 14' from house

Question: neighbor complaint about smoke from chimney

(July 2, 2014) Alexandra said:

Hi, our neighbours are exceptionally sensitive about any smoke which comes from our heat master firebox- installed in a brand new house 7 yrs ago, to council specs and just recently cleaned.

We wondered if extending the metal flue above the current height would help alleviated any smoke from their backyard, which sits diagonally adjacent to our house and below the chimney by at least 20 feet. We would do anything to avoid the aggression we incur every time we light a fire in the day!( not the evening)

The council have checked the fire and it conforms to all regulations.

Reply:

Alexandra

I read your query last night and then spent some time thinking about it as I don't see a cheap easy answer. Are you in the U.K. ? We've had a spate of requests around this topic, mostly from our U.K. readers of late.

A fireplace and chimney that meet standards and regulations for your country and city can still perform poorly or generate smoke complaints depending on local terrain or building features that cause poor draft or annoying smoke distribution patterns.

I would

- build a fire that generates visible smoke

- step outdoors and observe very carefully where smoke travels

- examine the building and terrain features as well as obtain data on prevailing wind directions in order to better understand downdrafts and directions of air movement

Discuss with a chimney expert:

- whether or not the chimney is drafting properly

- whether or not the chimney cap is the optimum design

- a concern for the effect of site features, terrain, wind on smoke distribution

- whether or not an extension of chimney height can possibly improve the situation (without having to go to a ridiculous or unsafe height), and the requirement for additional bracing if the chimney is extended

- choices of fuel that may reduce smoke output

- testing and confirmation of adequate combustion air

So that other readers can comment I'll also include this discussion in the FAQs above.

Do keep me posted and add additional information if you can - as the discussion will also assist others.

Question: change chiney from round to square flat

(July 24, 2014) Nicolas said:

I would like to change the chimney stack in the wall from 6" round to a square , flat version, so I will have more room in my bathroom!
Thank you.

Reply:

Watch out: changing a round chimney to a "flat" rectangular shape, even if it is the same total number of square inches, may severely restrict the chimney draft, making the chimney unsafe. You will need to consult a chimney expert to determine how much venting area is needed.

Question: don't like the ten foot chimney clearance rule

(Sept 9, 2014) Dave p. said:

I'm installing new trusses and changing the slope of the roof in my house, the chimney wont meet code with the new roof design. I submitted the plans to the building inspector and there was no mention of changing the chimney when the plans were approved.

I have all the permits to complete the project however does the inspector have the power to make me increase the chimney height even though there are no modifications to the chimney planned or permit requested for the work?

The chimney protrudes from the roof over three feet however doesnt meet the 10' rule.

I would have to extend the chimney another six and a half feet to comply and it would look horrible as it is attached to the front of the house and exposed to view from the street. Thanks for any advice or help you can give.

Reply:

Dave

The local building code compliance inspector has final legal authority over building permits and approvals and assertions of code compliance. More, if s/he does not approve of your chimney installation most likely it's a legitimate safety concern as well.

But there might be a misunderstanding of chimney height requirements involved. If you can show an authoritative source or can obtain a sign off from a local licensed design professional such as a licensed engineer or architect your local inspector may accept that alternative design.

My own preference is to meet the roof and chimney fire safety guidelines regardless. If it's a choice between aesthetics and burning down the new roof and house ... well enough said.

Question: chimney shared between two buildings: gas vs oil fired appliances

9/19/2014 Anonymous said:

I am a plumbing contractor and a month ego i installed a gas boiler and a gas water heater.When i wanted to connect the smoke pipe to chimney i found out that the house adjacent to the house i was working,was using the same chimney.One chimney for two houses.Is this common? The old heaters were oil fired boilers.

Converting to natural gas boilers who has the right to use the chimney,since the combustion is atmospheric ?

Reply: shared flue may be unsafe

Wow Anon, that gives a new meaning to "shared flue" and creates obvious problems and, I'd expect surely violates local and state or provincial building codes. There are obvious safety and control issues incuding:

- fuel conversion normally would require a flue inspection, cleaning, possibly even modification, but since the flue continues to be used by an oil fired heater in a separate building control is just about impossible.

- Draft regulation is up in the air

- Where some jurisdictions do permit gas appliance venting into a flue that also vents an oil fired appliance there are flue entry guidelines to minimize the risk of backdrafting.

I'd give this problem to the owner with a red tag on the heating system noting that there are code, legal and safety issues that can best be resolved by determining first whose chimney it is.

Question: chimney shared between two houses - gas fired heaters

(Sept 17, 2014) Anonymous said:
I am a plumbing contractor and a month ego i installed a gas boiler and a gas water heater.

When i wanted to connect the smoke pipe to chimney i found out that the house adjacent to the house i was working,was using the same chimney.One chimney for two houses.Is this common? The old heaters were oil fired boilers.

Converting to natural gas boilers who has the right to use the chimney,since the combustion is atmospheric ?

Reply:

ocal and state or provincial building codes. There are obvious safety and control issues incuding:

- fuel conversion normally would require a flue inspection, cleaning, possibly even modification, but since the flue continues to be used by an oil fired heater in a separate building control is just about impossible.

- Draft regulation is up in the air

- Where some jurisdictions do permit gas appliance venting into a flue that also vents an oil fired appliance there are flue entry guidelines to minimize the risk of backdrafting.

I'd give this problem to the owner with a red tag on the heating system noting that there are code, legal and safety issues that can best be resolved by determining first whose chimney it is.

Question: wood stove chimney outlet height vs surrounding properties

(Oct 6, 2014) Anonymous said:
I have a single storey flat roof extension on the rear of my 2 storey semi detached house, into which I wish to install a wood burning stove. Would the outlet pipe need to be above the main roofline of mine and surrounding properties.

(Nov 8, 2014) Anonymous said:
can a wood burning stove flue be installed on a single storey extension if so how high does the flue outlet have to be?

Reply:

Anon

Check the sketches in the article above. The 10 foot rule explains the clearance you need: both above the flat roof and 2 feet above the point at which a horizontal line from the chimney would touch the highest portion of the nearest roof.

Anon the chimney outlet needs to not only be proper height above the roof surface but proper distance from any opening that could take flue exhaust into the building. Details are given above using windows as an example.

Anonymous: if the chimney top is two feet above the ridge and assuming you're referring to gable end vents located in a roof end wall that is below the level of the same roof top the chimney should be in compliance.

Question: when measuring the chimney flue clearance to the adjancent structure, do I measure to the wall or would I measure to the edge of the overhang?

Hi,

I am wanting to put in a fireplace on my covered patio. The patio roof is only one story tall and attached to the house which is 2 story.

When measuring from the flue to the adjacent building, I'm very close to the 10ft rule. My question is, when measuring the flue to the adjancent structure, do I measure to the wall or would I measure to the edge of the overhang?

(Oct 23, 2014) Drew said:
I own a building in massachusetts that dates back to the early 1900's. After my building was built an adjoining building was erected and they subsequently had to raise my chimney to comply with code requirements since their building was 4 stories taller.

There's been a maintenance responsibility issue of late and I was under the assumption that my neighbor was required to maintain the chimney since they raised/extended it. I know New York law specifically cites this, section 27-860 adjoining chimney, but was curious if massachusetts has a similar code that you could provide me with.

(Oct 27, 2014) Anonymous said:
The brick chimney is adjacent to the gable vent. The gable vent is in the center of the wall.

The chimney is capped with openings about two feet above the roof line on the same side as the gable vent. I am worried that carbon monoxide from the chimney may be drawn into the gable vent.

Is the chimney in compliance with Southern Building Code if it vents two feet above roofline even though it is also about two feet away from the gable vent? Thank you for your kind assistance.

Question: backdrafting from wood fireplace

(Nov 11, 2014) mohammad said:
I get backfire insde my house coming from my wooden fireplace

Reply:

Mohammed what you describe is potentially dangerous. I would stop hpusing the chimney and ask for an inspection of the chimney for blockage, leaks, proper cap, and general safety. Let us know what you are told.

See BACKDRAFTING HEATING EQUIPMENT

 

Question: build stone around gas B-vent chimney

(Dec 4, 2014) Stacy said:
I have a b-type vent for a gas fireplace coming out my roof and I want to have a better look to it by putting stone around it. Are there rules about what material should frame around it to have stone to make it look 'pretty'?

Reply:

Smart question Stacey.

If you can tell me the brand and other information stamped into your B-vent we can dig out the manufacturer's exact specifications on and rules about enclosing the vent with a chimney chase - air space, air circulation, fire clearances.

See CHIMNEY CHASE CONSTRUCTION -

Question: height for outdoor furnace

(Dec 9, 2014) Anonymous said:
What is the correct height for an outdoor furnace and how close to property lines can the furnace be

Reply:

Anon presuming you mean a chimney venting a furnace - of some unspecified fuel - the heights are given in the article above. Let me know if any of that is unclear. Thanks - Ed.

Question: extending a short chimney over a bungalow

(Jan 15, 2015) Gary S said:
I have a bungalow and my chimney is very short and is no way near the top of the roof. If i was to make this 2ft above the roof line this will make my chimney very tall.....will this also make it unstable in windy conditions?

Reply:

Gary stability questions depend on the chimney materials and type of construction; two feet above a roof line is not usually enough to find wind damage but if the whole chimney free-height is substantial indeed you may need to add bracing.

Be sure you understand the height drawings accurately before extending the chimney height.

See BRACING for MASONRY CHIMNEYS

Question: making a hole in a B-vent for gas testing

29 January 2015 Anonymous said:
Is there an acceptable method of penetrating / sealing a double wall (B-vent) for CO testing?

Reply:

For B-vent chimneys and gas fired heaters I would NOT recommend making a hole in a B-vent and I'm surprised that it seems necessary. Why not measure flue gases readily accessible via the draft hood or at the chimney top? Measure instead at the heating appliance, chimney entry point, or chimney top.

Conversely, for *oil* fired heating appliances it's common practice to drill 1 or even 2 small diameter holes in the flue vent connector at the breech to permit insertion of a smoke tester and a CO2 measuring device or other gas testing instrument.

See DRAFT MEASUREMENT, CHIMNEYS & FLUESfor photos of this flue testing opening

Question:

(Mar 18, 2015) r kilts said:
whats the best way to cut down a too tall chimney that,s hard and dangerous to get to.

Reply:

RK

I see contractors either erect scaffolding or use a bucket truck. Watch out: dropping chimney components by an inexperienced contractor or worker could kill someone.

Question: What height does that exhaust have to be away from the deck surfac

(May 17, 2015) Derek said:
I have a roof top deck that has a chimney top located next to it. the Brick and mortar stop at about 4' high from deck surface and then a arrestor is about 18" tall.

What height does that exhaust have to be away from the deck surface, and do I need to turn vent at a 90 deg away from deck.

Imagine you walkout on to a rooftop deck and on the side of the house there is a chimney across the deck where the handrail stops on one side and continues on the other. The clearance from structure is about 15' ( the span of the deck)

Can I just add a metal chimney stack and if so, what height from deck surface does exhaust need to be. I have read a lot of things and the answer is varying. So I'm now asking it directly thank you

Reply:

Derek

please lighten our workload by asking questions in just one place. Thanks.

See

inspectapedia.com/chimneys/Chimney_Extensions.htm#FAQ

Question:

(6 days ago) Nassrine Niemi-Farhoody said:

I posted this question on another section of this website, but not sure where it is - I am re-posting the question here - my mother's neighbor built a building next to hers that is one story taller - there is no separation/space between the buildings and the taller building dwarfs her chimney (it vents the heating system and hot water heater) - what can she do to correct the lack of air flow? I have a picture that shows the extent of the problem. Thanks.

Reply:

See CHIMNEY HEIGHT EXTENSIONS

Question: am I required to raise a too-short chimney when selling my house?

(Aug 14, 2015) Patricia said:
i am selling a 40-year-old home in New Jersey.

The home has the original fireplace and chimney. The buyer's home inspector states that the chimney height does not meet code. Am I required to raise this chimney? We have never had any problems with smoke, etc. Also, there was no mention of any code violations 12 years Go when I purchased this house.

Reply:

Patricia

Watch out: Our first worry as a home owner, seller, occupant, or remote opinionater is that we should try not to kill anybody. So if a chimney is unsafe, your first concern as a home seller should be your safety and the safety of people who come after you in the home.

You want to be certain that the buyer / future occupants, are aware of any safety hazards that you know about. That's a separate question from who pays for what when buying or selling a home.

ONLY the local building code official can properly and legally declare that a building component "does not meet code" as he or she is the final legal local authority.

However a home inspector, speaking somewhat generally, might opine that she or he would expect a local code inspector to call out a component as "not meeting code" based on what the inspector knows about building codes.

My opinion is that code citations are a shortcut to be avoided, not only because of lack of legal authority, but because there can be plenty of hazards at a building that could kill someone or be very expensive to repair but that would never be identified as a "code violation".

In your specific case, I'd want to know what the inspector actually saw - it would be a more useful as well as more professional inspection report if it contained specifics rather than a shortcut statement.

If we were to *guess* that the inspector thinks the chimney lacks proper clearance above the roof (as you can see in the article above) that's an important call to make not so much because it could be called out as a violation by the local inspector as because it is unsafe: a too-short chimney increases the risk of a house fire.

The questions of draft adequacy are separate from the fire risk.

Happily for you the course of action is easy:

Have the chimney inspected by a professional such as a chimney sweep / repair company who is certified by the National Chimney Sweeps guild. If that pro finds any safety hazards regarding the chimney they should be repaired. Typically, extending a chimney top height to improve clearance is not a major expense and will certainly be less than 1/10 of a % of the price of a home in New Jersey.

About what was not noticed when you bought the home, presuming that the chimney has not lost height through damage, the conditions would have been present then even if your inspector didn't mention them - vs current conditions such as a deteriorated flue, blocked flue, creosote-coated flue that need cleaning or repair.

Question: how far must drywall be from a chimney?

(Sept 12, 2015) Wendy said:
Since installing a heat pump and an efficient furnace, only my hot water tank vents through my chimney. Doing some renos and want to know how far must the drywall be from the chimney?I am hoping to gain an inch or 2 in this area.

Reply:

Wendy: I can't guess, given we don 't know the chimney type, materials, nor fuel being vented. I'm guessing you're discussing a metal chimney of some type. We give fire clearances for metal chimneys of various types at

inspectapedia.com/chimneys/Metal_Chimney_Clearances.php

 

Question: chimney height from burner top?

(Oct 7, 2015) Goutam Pramanik said:
Is it possible to place the chimney at a height of 3'6" from the burner top?

Reply:

I don't understand the question. "Burner top" ? What burner, what fuel, what kind of chimney, what total height, etc. remain questions that need to be answered.

Question: B-vent top near masonry chimney

(Oct 26, 2015) Nick said:
I have a vertical B-Vent from a furnace that terminates a few feet horizontally from a masonry chimney. The B-vent terminates vertically 2' above my roofline, but it is not above the masonry chimney. Does the masonry chimney count as a "vertical wall"?

Does this mean that my B-vent is not high enough?

Reply:

No, in my opinion a masonry chimney should not ocunt as a vertical wall.

Question: chimney for pizza oven on a screened porth

(Dec 22, 2015) Joe S said:
I have a very small pizza oven (terracotta)in a screened in porch with a metal roof, it's well ventilated.

The stacks are thru the metal roof (straight up) with a cap. How far does this need to be from the top of the metal roof. I am assuming 3' would be acceptable, hopefully. Thanks, Joe S.

Reply:

CHIMNEY HEIGHT for Types L & Type B Vents address this

Joe you don't name the fuel; if you are using gas fuel, take a look at the B-vent chimney to roof clearances in the table in the article just above.

(Dec 24, 2015) Joe S said:

Sorry about that. It's a small round (terracotta) wood burning oven just 22" in diameter and generates about 500 degrees(F) perfect for one 12" Pizza. Currently, I have it placed 3' (high) from the bottom of the slanted steel roof to the top of the stack.

The screened room is an addition and the portable oven is 15 feet for the house. Another question for which I can't find an answer, is...

what is the approximate temperature by the time the smoke gets to the top of the chimney if the temperature inside the oven is approximately 500 degrees and the stacks are about 8 foot from the oven to the top of the pipe/stack (on the roof).

I am not too worried about that because here in Arizona that roof can get to well over 100 degrees when that outside temperature is 110 degrees in the summer but still curious to determine the temperature by the time it gets to the top of the pipes/stacks. Merry Christmas and thanks for the help. Joe S.

Mod said

Interesting question, I'll have to research it. The temperature drop vs height will depend on a number if variables including at least

Height

Chimney materials

Outdoor temperature

Wonderful velocity

Temperature of entering flue gas

Gas density

Gas velocity or draft

Cleanliness of the flue

Site specifics

Sun gain

Humidity

Question: neighbor's chimney too close to our house

(Feb 9, 2016) Stewart said:

Our neighbour has built an external brick chimney stack between his and our house. The original space was 105 cm and is now halved.

The stack faces our gable end which has an air brick and tiled roof air vent facing the stack. Their rainwater gutter which ran parallel to our gable end has been diverted around the stack and now overflows rain water down our gable end wall which bounces off the concrete passage well above our damp proof course.

What to do..I have already mentioned to the builder and owner that this would happen but to no avail.
Your help would be appreciated since we are about to sell.

Reply:

Stewart,

It is certainly not acceptable for a neighbour to drain their roof onto another building's wall.

If the neighbor won't correct the problem you may get help from your local building department. Use our page bottom CONTACT link to send me some photos that illustrate the situation and we can comment further. Keep me posted.

See details at CHIMNEY CLEARANCE to NEIGHBORS

(Feb 14, 2016) Stewart said:

Many thanks for your assistance.
Council Building Inspector on site in a few days and issued a 14 day remedy notice.
Builder back on site next morning.

Owner suggested that our cavity wall will absorb the gutter overflow without any damage as that was its function and not cause any damp.spector

It had been like that since Xmas and he knew about it all this time but said and did nothing.

A local builder gave the same advice.
What clinched it was I read out your first sentence to the Inspector.
If you would like photos do you have an email address ?

Moderator said:

Stewart:

Stewart: you will find our email at the page bottom or top CONTACT link. I'd be glad to see photos of the situation and I may be able to comment.

I'm not familiar with a good construction practice that deliberately sends water into a cavity wall and I'm doubtful that over the life of a building water can run inside of a building wall without making trouble.

I'd need to understand the construction of your "cavity wall" but if you mean that there is a masonry wall with an air space between the outer brick or stone and the rest of the wall structure, even with good wall-bottom drainage, it would be a poor practice to direct water against the wall.

The wall drainage system is likely to be overwhelmed by water way beyond its design level, and continued water and moisture in the wall invites sending moisture into the interior-side wall components where we risk - various troubles depending on the materials of construction. I'd worry about mold, effloresence, rot, and electrical wiring damage as well as damage to HVAC systems if the walls include ductwork.

Question: Godin Cervalou which needs a 15 cm flue but the fitters couldn't get this dimension down the chimney

(Feb 12, 2016) Sue Wilson said:
We bought a Godin Cervalou which needs a 15 cm flue but the fitters couldn't get this dimension down the chimney. How can we measure the width of the chimney please and can anything be done if it turns out to be 14 cm as suspected?

Reply:

The chimney interior dimensions are ususally visible through the chimney throat, through a chimney entry thimble in the chimney side, or at the chimney top. You may however need a Chim-Scan camera inspection to find an obstruction or damage that you can't see from these openings. Try first inspecting from the chimney cleanout using a good light and a mirror.

Question: I would like to put a wooden stove heater into my conservatory.

(Mar 10, 2016) Craig said:
I would like to put a wooden stove heater into my conservatory. I believe where I could put the heater would be 10 feet away from the external walls of the house. The house is 3 stories. Does this give me enough clearance, would this be ok. I'd like to try and avoid a 3 storey flue. What are your thoughts?

Reply:

Craig

In most places you need a building permit and fire department inspections to install a woodstove. Those steps will review your local clearances from combustibles. I can't answer a general safety question from a brief e-text as there could certainly be unsafe installation details that could burn down the building.

Question: short chimney in converted log home

(Mar 28, 2016) Anonymous said:
I'm purchasing a converted log home. It has a gas furnace and that chimney looks short, it also has a fireplace that was converted to gas, and the inspector said that chimney was too short as well. Can I use chimney pots to extend the chimneys?

Reply:

Your local building or fire inspector might accept a chimney pot, depending on its design, materials, and height.

See CHIMNEY HEIGHT EXTENSIONS

Question: gazebo next to outdoor free-standing fireplace

(Apr 7, 2016) Ernesto said:
I am building a gazebo next to an existing outdoor free standing fireplace. Does the chimney height and distance from the roof of the gazebo require the same code clearances as those for a home? i.e. 2 ft above the highest peak within 10 ft.

Reply:

I would respect those clearances - after all, Gazebos burn too.

Question: replace masonry chimney that is detroratoring with metal?

(May 10, 2016) Becky said:
Our church has a masonry chimney that is detroratoring and we are wondering if we could replace that with a metal chimney. We have one estimate for repair for almost $13,000 and we were looking at maybe shorting the chimney but that appears to be against code. It is a forced air heating system.

Reply:

Becky,

You can usually replace a masonry chimney with a metal one, typically insulated stainless steel; But of course if the old chimney is a hazard it'll need to be removed. Removal is also an expense.

Depending on where the heating furnace is located it may be possible to eliminate the chimney entirely, going to a direct-vent installation. Ask your heating service company about this option.

That may be what you meant by "shorting the chimney" - I'm not sure. Certainly you can't just arbitrarily make a chimney literally "shorter" - without fire, function and other concerns.

Search InspectApedia.com for DIRECT VENTS / SIDE WALL VENTS to see details of that option.

Question: explaining the ten foot rule for chimney clearance

(May 18, 2016) Dean said:
Just want to be sure that I understand things correctly. If installing a chimney (framed chase to extend up from the roofline) the nearest part/structure of the house must comply with the 10' rule, which in my case would be the outside edge of the overhanging soffit of the higher roof line and not the outside wall of the house below that soffit?

Reply:

Yep. Clearances address fire safety so IMO we need to include all building components that might be affected. See CHIMNEY HEIGHT & CLEARANCE CODE

Question: neighbor's unsafe pellet stove?

(June 3, 2016) Liz said:
My neighbor has a pellet stove with the chimney coming out the side of the house. The pipe goes up maybe 8 ft and is well below the roof lines! We r starting to see black in our ceilings and I'm thinking its from the smoke from their chimney.

They told us that they are within the requirements but that just doesn't make any sense to me! Is there a specific code I could look at to show them that the chimney should be above the roof?

Reply:

Possibly you're quite right. A chimney that does not terminate above the roof line is not likely to be correct and could be a fire hazard; it also is a clue that a system was installed without the required building permit and safety inspections and approvals.

Also see CHIMNEY CLEARANCE to NEIGHBORS

 

Question:

2016/07/21 Gary said:
We have a mason fire place ( fire brick ) and the installer says do not install a chimney cap. He says it is not required and it affects how the flu works

Reply:

He' wrong. See CHIMNEY CAP & CROWN DEFINITIONS and also CHIMNEY DRAFT & PERFORMANCE

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Continue reading at CHIMNEY HEIGHT & CLEARANCE CODE - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see CHIMNEY HEIGHT & CLEARANCE CODE FAQS-2 - set #2 of questions & answers about chimney top clearance distances

Or see these

Recommended Articles

• CHIMNEY CODES & STANDARDS
• CHIMNEY HEIGHT & CLEARANCE CODE

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CHIMNEY HEIGHT & CLEARANCE FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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