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  1. #1
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    Default Chimney flue firestopping

    I've just received a call from my clients realtor. Real sweet gal. The seller had his chimney inspected by a "Chimney Guy" who produced a report saying that the chimney flue is properly firestopped at the 8' to 10' level. I see nothing in the IRC at R1001.16 about any 8' or 10' level. Every diagram I've ever seen about chimney flue pipe firestopping indicates it needs to be at the point where the flue pipe passes into the attic (or between floors). I called this flue out as not properly firestopped. I'm curious what other inspectors might think?

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    Default Re: Chimney flue firestopping

    You are absolutely correct for calling that out.

    Anytime a fire can go from a wall area, up through a chase, and into the attic area it is a violation.

    Draft stop at the ceiling line.


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    Default Re: Chimney flue firestopping

    From the 2006 IRC. (underlining is mine)

    - R602.8 Fireblocking required. Fireblocking shall be provided to cut off all concealed draft openings (both vertical and horizontal) and to form an effective fire barrier between stories, and between a top story and the roof space. Fireblocking shall be provided in wood-frame construction in the following locations.
    - - 1. In concealed spaces of stud walls and partitions, including furred spaces and parallel rows of studs or staggered studs; as follows:
    - - - 1.1. Vertically at the ceiling and floor levels.
    - - - 1.2. Horizontally at intervals not exceeding 10 feet (3048 mm).
    - - 2. At all interconnections between concealed vertical and horizontal spaces such as occur at soffits, drop ceilings and cove ceilings.
    - - 3. In concealed spaces between stair stringers at the top and bottom of the run. Enclosed spaces under stairs shall comply with Section R311.2.2.
    - - 4. At openings around vents, pipes, ducts, cables and wires at ceiling and floor level, with an approved material to resist the free passage of flame and products of combustion.
    - - 5. For the fireblocking of chimneys and fireplaces, see Section R1003.19. (Jerry's note: see below.)
    - - 6. Fireblocking of cornices of a two-family dwelling is required at the line of dwelling unit separation.

    - SECTION R1003
    - - MASONRY CHIMNEYS
    - - - R1003.19 Chimney fireblocking.
    - - - - (Section 1003 is not applicable as that is not a masonry chimney, thus 1003.19 is not applicable)

    Fireblocking is to be at all ceiling and floor levels *and* every 10 feet horizontally (such as for parallel row or staggered stud walls).

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    Default Re: Chimney flue firestopping

    i would also require insulation guards for the flue!


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    Default Re: Chimney flue firestopping

    I agree with Brian:

    Insulation shield is missing. This is allowing insulation to contact the B vent. Today's requirements (G2426.4) states; 'When passing through insulated assemblies, an insulation shield shall be installed to provide clearance between the vent and the insulation material, When vents pass through attic space, the shield shall terminate not less than 2 inches above the insulation materials and shall be secured in place to prevent displacement." Have the proper shield installed to prevent the insulation from contacting the B vent.

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  6. #6
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    Default Re: Chimney flue firestopping

    Thanks guys! I've called out dozens of these over the years, but this is the first time I've ever been challenged about it. I couldn't easily get closer to the flue chase, but I thought I could see everything I need to see about the absent firestopping (not there). When the "Chimney" company said "Firestop is installed at the required 8' - 10' ceiling level since the pipe is not passing thru a second floor, only one firestop is needed." Of course, I was standing on the ceiling joists when taking the photo. Anyway, it just threw me. I'm sticking to my guns on this one!


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    Default Re: Chimney flue firestopping

    Jerry

    How would R602.8 apply to a steel framed house? From inside the attic I could look down into a wall cavity?

    Jeff

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    Default Re: Chimney flue firestopping

    Quote Originally Posted by brian schmitt View Post
    i would also require insulation guards for the flue!
    Quote Originally Posted by Darren Miller View Post
    I agree with Brian:

    Insulation shield is missing.
    First, HIs cannot "require" anything, we can only "write it up for correction".

    Second, no insulation shield is missing *at this time* as there is no place to put insulation. Now, once the proper firestop is installed, giving a flat surface around the chimney where insulation could be placed, then, yes, an insulation shield is then required.

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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Jerry Peck View Post
    Second, no insulation shield is missing *at this time* as there is no place to put insulation. Now, once the proper firestop is installed, giving a flat surface around the chimney where insulation could be placed, then, yes, an insulation shield is then required.
    In my opinion it IS missing. The code states:"'When passing through insulated assemblies".

    It is passing through an insulated assembly so therefore it is required!


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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Jeff Euriech View Post
    How would R602.8 apply to a steel framed house? From inside the attic I could look down into a wall cavity?
    .

    Jeff,

    With steel frame construction it would depend on the installation aspect, such as: (from the 2006 IRC)


    -> R1001.12 Fireplace fireblocking.Fireplace fireblocking shall comply with the provisions of Section R602.8.


    -> M1801.9 Fireblocking.Vent and chimney installations shall be fireblocked in accordance with Section R602.8.

    -> G2425.15.4 (501.15.4) Clearances. Chimneys and vents shall have airspace clearance to combustibles in accordance with Chapter 10 and the chimney or vent manufacturer’s installation instructions. Noncombustible firestopping or fireblocking shall be provided in accordance with Chapter 10.

    However, each of the above could be argued that they are applicable to combustible construction only.

    In South Florida where we used steel framing for non-load bearing interior walls, we also used wood trusses, which put us back into the protection of combustible material, however, in your photo you are also using steel trusses, but ... you still have OSB roof sheathing to protect (unless it is fire retardant treated).

    What we always used for that draftstopping was 1/2" gypsum board as that is all that is required when a draftstop is installed in a floor/ceiling area or in an attic. In steel construction the draftstopping is there to seal off the concealed spaces from allowing them to generate drafts which could lead to the spread of smoke and fire.

    In steel framing the term changes from fireblocking to draftstopping, and I am at a loss right now to find a reference to it for that use in the IRC.

    Logic and common sense tells you you need at least draftstopping at concealed spaces where the vertical concealed spaces intersect with horizontal concealed spaces, and vice versa.

    Ever tried to ignite the paper on the back of gypsum board? I have, with a MAP gas torch even, and, sure, I could get the paper to flame up and burn ... as long as I held the torch on it, but as soon as I removed the torch the flames stopped. I ended up with a 6" square piece of gypsum board with the paper charred, but the charred remains were still on the back of the gypsum board. In a case like that, I would not be concerned about the gypsum board paper burning, I would be concerned as to why there was a MAP gas torch lit and inside my walls.




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    Default Re: Chimney flue firestopping

    Jeff,

    Adding to the post above, but making a separate post for it:

    In those areas you are asking about in your photos, how are they going to insulate those areas if not by putting gypsum board, or something similar, over the openings?

    Not only would you be addressing draftstopping with the gypsum board over the top of those open vertical chases, but you would then be allowing for proper insulation.

    Thus, the argument could be turned from draftstopping to energy efficiency code requirements for attic insulation.

    Solves two problems with one solution.

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  12. #12
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    Default Re: Chimney flue firestopping

    If for nothing else the ceiling needs to be insulated because the walls below are not insulated. Saying that, collar and plate of some kind of stop to put the insulation on which would also create a draft stop. Covers both by doing one. End of story.


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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Ted Menelly View Post
    If for nothing else the ceiling needs to be insulated because the walls below are not insulated.
    Ted,

    Precisely what I was pointing out in my post just above yours. Your wording may be better?

    Saying that, collar and plate of some kind of stop to put the insulation on which would also create a draft stop. Covers both by doing one.
    Yep, that'll do both.

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    Default Re: Chimney flue firestopping

    Jerry and Ted

    Thanks for the good information. This house was built in 1997 and was bank owned. I was surprised to find steel framing when I went into the attic. This was my first steel framed house and I wasn't 100% sure of what I should be looking for. I decided to take the common sense approach and I called out the opening due to missing insulation. I recommended that it be covered with gypsum board and insulation.

    After I got back to the office, I pulled out the 2006 IRC to see what current codes might apply to new built steel framed homes. However, I was having difficulty trying to interpret some of the codes.

    I also called out the pull down ladder in the garage due to not meeting the fire separation requirements between the garage and attic. I assumed due to the OSB roof sheathing that this would be a problem. Was I correct on that?

    Just for the fun of it, what is the correct way to attach a pull down ladder to steel framing? Kind of hard to use nails.

    Jeff

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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Jeff Euriech View Post
    I also called out the pull down ladder in the garage due to not meeting the fire separation requirements between the garage and attic.
    Therein lies a problem, which was discussed quite recently at some length, because you stated "fire separation requirements" and there are no "fire separation requirements", only "separation" requirements.

    (Don't get Aaron started on this again, we finally resolved it, sort of ... )

    I assumed due to the OSB roof sheathing that this would be a problem. Was I correct on that?
    Only in that it makes for combustible construction exposed in the attic, and thus, even though the trusses themselves are not wood, that may well put the firestopping requirements for wood trusses back into play (I did not fully approach that issue in my information above - but obviously have not stopped thinking it could be a problem and would need to installation of actual fireblocking ...

    Just for the fun of it, what is the correct way to attach a pull down ladder to steel framing? Kind of hard to use nails.

    All of those ladders I've seen state 16d common nails, so ... that would mean boxing the steel trusses in with 2x wood and nailing the pull-down stair to the properly anchored wood. Otherwise, either an engineer would have to design it, or the manufacturer's engineering department would need to design for it - either way it is "engineering" which provides for the alternate method of installation and attachment.

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  16. #16
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    Default Re: Chimney flue firestopping

    The metal will heat up and twist and the OSB will burn.

    Obviously if a fire is going that good then a simple sepaeration will only delay it slightly but that slight delay may make all the difference to that side of the roof burning and the metal twisting and collapsing. If the pull down stairs burn thru it would only be minutes difference before the drywall burned thru.

    Personaly I always built with a min of 5/8/x drywall between the house and atic from the garage and just about always in the entire garage. That gives things a few more minutes even if it is not an actual fire seperation.


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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Jerry Peck View Post
    First, HIs cannot "require" anything, we can only "write it up for correction".

    Second, no insulation shield is missing *at this time* as there is no place to put insulation. Now, once the proper firestop is installed, giving a flat surface around the chimney where insulation could be placed, then, yes, an insulation shield is then required.
    jerry
    jerry ,
    i can require it because i am also a jurisdictional inspector and i said" i would also require insulation shields".this was in response to the previously stated missing firestopping. i didn't think i had to repeat that fact but i need to be cognisant of short attention spans in the future i suppose


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    Default Re: Chimney flue firestopping

    Quote Originally Posted by brian schmitt View Post
    i can require it because i am also a jurisdictional inspector

    I did not see where you said you were a code inspector for an AHJ, so, if you said that, I sure missed it.

    Simply repeating "I require" means nothing. Saying you are an AHJ code inspector, that changes it, however, *IF* you are enforcing the IRC, you have tight bounds to stay within, such as:

    (underlining is mine)
    R104.1 General.
    The building official is hereby authorized and directed to enforce the provisions of this code. The building official shall have the authority to render interpretations of this code and to adopt policies and procedures in order to clarify the application of its provisions. Such interpretations, policies and procedures shall be in conformance with the intent and purpose of this code. Such policies and procedures shall not have the effect of waiving requirements specifically provided for in this code.

    Usually, when I post the above, I underline the last line, however, you are "requiring" something *above and beyond* what the code "requires", you are not 'allowing them to do less', that is good, but not defensible should you be challenged on it, not unless your AHJ has amended the code to include the higher standard.



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    Default Re: Chimney flue firestopping

    jerry,
    thanks for the reply. i was aware that there is a chimney in the photo and as stated by the op. the installation instructions for these chimnies usually require a certain clearance to combustibles ergo the guards. this is where the require part is a code issue.


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    Default Re: Chimney flue firestopping

    Quote Originally Posted by brian schmitt View Post
    the installation instructions for these chimnies usually require a certain clearance to combustibles ergo the guards. this is where the require part is a code issue.

    The installation instructions also (almost always if not "always") require a firestop at a ceiling level too, which makes that also a code issue.

    Another thing I was pointing out was that, *as installed* no insulation stop is required because *no insulation can be placed around that chimney/vent*, this is because there is no firestop installed.

    That means all the insulation fell down on top of the firebox - which is also a code issue as no insulation is (as I recall) allowed on top of the firebox either.

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  21. #21
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    Default Re: Chimney flue firestopping (Update)

    I've just spoken with the "Chimney Guy". I never questioned that the flue chase might be firestopped down lower, but only that I believed that it should be where it passed into the attic. However, he has more-or-less convienced me that it is. I've attached a little sketch. The fireplace sits on an exterior wall, but the roof covers a large rear patio. The patio soffit is at normal ceiling level, but the ceiling where it fireplace is at is about 14- or 16-feet. Technically, the fireplace chase does pass into the attic at normal ceiling height because the attic above the patio communicates with the attic above the living space. The photo I posted with the original comment was taken from above the living area. As you can see in the background, the patio joists are much lower. He says the firestop is at that level. I didn't look down the chase because I didn't feel I needed to. I don't doubt his word that there is a firestop at the lower level. Any comments?

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    Default Re: Chimney flue firestopping

    Robert,

    The top only needs to be fireblocked if that which is shown in my annotation of your drawing is present. Then BOTH would be required.

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  23. #23
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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Jeff Euriech View Post
    Jerry and Ted

    Thanks for the good information. This house was built in 1997 and was bank owned. I was surprised to find steel framing when I went into the attic. This was my first steel framed house and I wasn't 100% sure of what I should be looking for. I decided to take the common sense approach and I called out the opening due to missing insulation. I recommended that it be covered with gypsum board and insulation.

    After I got back to the office, I pulled out the 2006 IRC to see what current codes might apply to new built steel framed homes. However, I was having difficulty trying to interpret some of the codes.

    I also called out the pull down ladder in the garage due to not meeting the fire separation requirements between the garage and attic. I assumed due to the OSB roof sheathing that this would be a problem. Was I correct on that?

    Just for the fun of it, what is the correct way to attach a pull down ladder to steel framing? Kind of hard to use nails.

    Jeff
    Most manufactures allow 3/8s bolts. Of course in wood it would be a lag bolt but in the metal I am sure 3/8s bolts with lock washers and nut would suffice


  24. #24
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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Jerry Peck View Post
    Robert,

    The top only needs to be fireblocked if that which is shown in my annotation of your drawing is present. Then BOTH would be required.
    Jerry,
    Thanks again for your response, and your effort with my little sketch. While I did not put my eyeball on the opposite side of the stud wall forming the chase it appears to me that it is sheathed by virtue of the insulation visible in the original photo. I suppose it could be batts, but do they even make batts with cellulose insulation?

    Additionally, the fireplace contractor I've been talking with, and who did the followup inspection, says he has talked to the manufacturer (regarding this specific house) and they have told him it is okay. It isn't that I don't trust the guy. He seems to be very knowledgeable and claims to be code certified in the fire code (he didn't just say, "fire code" he gave chapter and verse).

    If it is true that the manufacturer has approved this don't, we as inspectors, generally differ to the manufacturer? And, can you guide me too anything in the IRC that supports your conclusion?

    BTW, the fireplace guy says the distance from the top opening of the chase to the existing firestop below is about 4-feet (if that makes any difference).


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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Robert Autrey View Post
    And, can you guide me too anything in the IRC that supports your conclusion?
    From the 2006 IRC. (underlining is mine)

    - R502.13 Fireblocking required.
    Fireblocking shall be provided in accordance with Section R602.8.

    - R602.8 Fireblocking required.


    Fireblocking shall be provided to cut off all concealed draft openings (both vertical and horizontal) and to form an effective fire barrier between stories, and between a top story and the roof space. Fireblocking shall be provided in wood-frame construction in the following locations.
    - - 1. In concealed spaces of stud walls and partitions, including furred spaces and parallel rows of studs or staggered studs; as follows:
    - - - 1.1. Vertically at the ceiling and floor levels. (Jerry's note: If the stud space is open on the back side in the attic, it is no longer "concealed space", it is simply "attic space", thus this not apply as this is for "concealed spaces", thus the only location fireblocking is required or needed is the stud cavities at the soffit "ceiling" level. If the wall is covered with gypsum board (for example) over both vertical surfaces all the way to the top plate, the the top part of the stud is a "concealed space". Then the stud cavities would need to have fireblocking installed at the lower "ceiling" (soffit) level AND at the higher ceiling level- because the concealed spaces are required to be fireblocked at "ceiling ... levels".)
    - - - 1.2. Horizontally at intervals not exceeding 10 feet (3048 mm).
    - - 2 At all interconnections between concealed vertical and horizontal spaces such as occur at soffits, drop ceilings and cove ceilings. (Jerry's note: This also requires the fireblocking at the lower soffit level as the walls below have stud cavities which are concealed spaces.)
    - - 3. In concealed spaces between stair stringers at the top and bottom of the run. Enclosed spaces under stairs shall comply with Section R311.2.2.
    - - 4. At openings around vents, pipes, ducts, cables and wires at ceiling and floor level, with an approved material to resist the free passage of flame and products of combustion. (Jerry's note: This section would also apply should there be any wires, piping, ducts, etc., in the stud cavity concealed spaces.)
    - - 5. For the fireblocking of chimneys and fireplaces, see Section R1003.19.
    - - 6. Fireblocking of cornices of a two-family dwelling is required at the line of dwelling unit separation.

    Hopefully, that helps explain the drawing.



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    Default Re: Chimney flue firestopping

    For your other questions (that post was long enough as it was).

    Quote Originally Posted by Robert Autrey View Post
    I suppose it could be batts, but do they even make batts with cellulose insulation?
    Not that I am aware of, and it would be quite difficult as cellulose is quite heavy compared to fiberglass.

    It is common to find cellulose on horizontal areas and fiberglass batts on vertical surfaces like those shown in your photo.

    Here is another thing to consider: The wall *below* the soffit is insulated the required R-value for exterior walls, however, the wall *above* the soffit is *required to be* insulated to the same value as the ceiling as it is "attic" area by virtue of being exposed to the attic.

    If it is true that the manufacturer has approved this don't, we as inspectors, generally differ to the manufacturer?
    If the manufacturer's printed installation instructions (not just some engineer who says 'Oh, well, yeah, that should be okay') are followed, AND, the building code is followed, there are only a few exceptions where the two do not match or where the manufacturer's installation instructions are more stringent - i.e., there are very few time where the manufacturer's installation instructions may be lesser than code, and then code applies.

    BTW, the fireplace guy says the distance from the top opening of the chase to the existing firestop below is about 4-feet (if that makes any difference).
    No difference other than this: That's how far down the lower ceiling is, right?

    What they did at the time of construction was to fireblock at "the lower ceiling" but not at "the upper ceiling". Now look at my annotation on your drawing, visualize the exterior soffit in that drawing as being "the lower ceiling" in your photo, not look at the "higher ceiling" in the drawing as though it were "the higher ceiling" in your photo.

    There is your fireblocking at the lower ceiling and at the upper ceiling, just what I was supposing as 'what if' with the two other comments on your drawing.

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    Default Re: Chimney flue firestopping

    Here is another "what if" scenario:

    Look at your photo and you will see the lower ceiling down on the left, and the lower drop to the fireblocking "within" the chase, so, suppose "what if" the insulation were removed from that wall we are looking on the left side of the chase in your photo?

    Interesting idea, right?

    Now what do you have? Open studs. And you already have fireblocking at "the ceiling level" of the concealed spaces, and no concealed spaces above that fireblocking, right? Means no fireblocking at the top would be required.

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  28. #28
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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Jerry Peck View Post
    For your other questions (that post was long enough as it was).

    No difference other than this: That's how far down the lower ceiling is, right?

    What they did at the time of construction was to fireblock at "the lower ceiling" but not at "the upper ceiling". Now look at my annotation on your drawing, visualize the exterior soffit in that drawing as being "the lower ceiling" in your photo, not look at the "higher ceiling" in the drawing as though it were "the higher ceiling" in your photo.

    There is your fireblocking at the lower ceiling and at the upper ceiling, just what I was supposing as 'what if' with the two other comments on your drawing.
    I'm not sure I follow what you're driving at here, but it seems to me that your note at the code reference says it all. All concealed vertical spaces must be fireblocked from communicating with the attic space. By that measure it wouldn't matter if the lower firestop was just two feet below. Right? Assuming the chase is sheathed, making it a concealed space, it would have to be firestopped at both ceiling levels. Right? That's what I understood from your sketch annotations.

    Thanks again.


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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Robert Autrey View Post
    I'm not sure I follow what you're driving at here,
    Try this attachment.

    but it seems to me that your note at the code reference says it all. All concealed vertical spaces must be fireblocked from communicating with the attic space. By that measure it wouldn't matter if the lower firestop was just two feet below. Right? Assuming the chase is sheathed, making it a concealed space, it would have to be firestopped at both ceiling levels. Right? That's what I understood from your sketch annotations.

    Thanks again.
    Correct.

    Unless the concealed spaces are changed, in the attachment, the wall to the left of the chimney/vent is no longer concealed space - it is open to the attic.

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  30. #30
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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Jerry Peck View Post
    Try this attachment.



    Correct.

    Unless the concealed spaces are changed, in the attachment, the wall to the left of the chimney/vent is no longer concealed space - it is open to the attic.
    Thanks! I've got it. It is a bit of an unusual situation, or at least slightly uncommon.

    Thanks so much for your effort in helping me understand this.


  31. #31
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    Default Re: Chimney flue firestopping

    Issue resolved!

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  32. #32
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    Cool Re: Chimney flue firestopping

    Mr. Autrey. In the future if you have any problems with fireplaces feel free to give me a call. James Gibson, C.C.Chimney & Outdoor Kitchens, 361-855-4937. I am certified through the National Fireplace Institute; the most rigorous fireplace testing in the UNITED STATES, recognized by all fireplace manufacturers and recommended on the front page of every installation manual. Mr. Perkins, thank you for your valuable knowledge in the code enforcement industry, you are greatly respected. My certification # is 148440, I am also certified in gas burning appliances.
    Thanks,
    James Gibson
    ccchimne@yahoo.com


  33. #33
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    Default Re: Chimney flue firestopping

    Perkins, excuse me Peck. Sorry about the misspell. I am working on too many things at once.


  34. #34
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    Default Re: Chimney flue firestopping

    Quote Originally Posted by James Gibson View Post
    Mr. Autrey. In the future if you have any problems with fireplaces feel free to give me a call. James Gibson, C.C.Chimney & Outdoor Kitchens, 361-855-4937. I am certified through the National Fireplace Institute; the most rigorous fireplace testing in the UNITED STATES, recognized by all fireplace manufacturers and recommended on the front page of every installation manual. Mr. Perkins, thank you for your valuable knowledge in the code enforcement industry, you are greatly respected. My certification # is 148440, I am also certified in gas burning appliances.
    Thanks,
    James Gibson
    ccchimne@yahoo.com
    James,
    I certainly will contact you if another issue arises that I'm concerned about. Of course, as it was, this one was probably never really an issue to begin with given that there was no actual sheathing. Oddly, it was the cellulose insulation sticking to the fiberglass batts that threw me. I thought, "No way cellulose insulation could be staying put in those wall cavities without sheathing on the other side." I've tried really hard to stop myself from assuming, but somehow I keep doing it. Anyway, thanks for you courteous help on this.


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    Cool Re: Chimney flue firestopping, fireblocking, and support.

    That offset and return is improperly supported. Regardless of lower firestopping and fireblocking, it must be fireblocked vertically to the roof deck. Insulation can fall down there, which is a hazard. The joints in the offset should have screws in the outer casing to reinforce the joints in the offset. The total system height would need to be checked against the listed instructions allowance based on the offset. Of course, this should get a level II inspection.

    James, click on the FIRE Service button to read about the most comprehensive TRAINING in the hearth industry---not just a test. FWIW, I'm an NFI Experienced Instructor and Master Hearth Professional along with being a Certified Fireplace Inspector. All you need now is your pellet cert. to get your MHP. Contact your HPBA Affiliate for possible dates this Spring or you could come to Reno for the HPBA EXPO. Hope to see you there!
    Bob

    Keep the fire in the fireplace.

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    Default Re: Chimney flue firestopping, fireblocking, and support.

    Quote Originally Posted by Bob Harper View Post
    Regardless of lower firestopping and fireblocking, it must be fireblocked vertically to the roof deck. Insulation can fall down there, which is a hazard.

    Bob,

    Welcome back, you've been missed.

    By "fireblocked vertically to the roof deck. Insulation can fall down there," you mean it needs baffles around that opening where the chimney/vent is to keep the insulation from falling down into that opening and onto the fireblocking below, right?

    If not, I am missing something and need you to explain it.

    Also, Bob, which is the correct terminology for that: a) chimney; b) vent?

    Thanks,

    ~~~~~~~

    Robert,

    Now, at the fireblocking you said was below at the lower ceiling level ... I don't see it in the photo.

    I see the lower ceiling through the the now open studs, I see the insulation between the ceiling joists, and see the blocking between the vertical studs and the ledge for those joists, but ... I do not see the fireblocking down there you said was there????

    That fireblocking would need a proper insulation shield to keep the insulation back from the chimney/vent.

    Jerry Peck, Construction / Litigation Consultant
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  37. #37
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    Default Re: Chimney flue firestopping, fireblocking, and support.

    Quote Originally Posted by Jerry Peck View Post
    Bob,

    Robert,

    Now, at the fireblocking you said was below at the lower ceiling level ... I don't see it in the photo.

    I see the lower ceiling through the the now open studs, I see the insulation between the ceiling joists, and see the blocking between the vertical studs and the ledge for those joists, but ... I do not see the fireblocking down there you said was there????

    That fireblocking would need a proper insulation shield to keep the insulation back from the chimney/vent.
    Jerry,
    I just didn't post my new photo. I did confirm it was there. Here's the pic.

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    Default Re: Chimney flue firestopping

    Robert,

    Okay, I see the fireblocking, however, your new photo shows that there are now two uninsulated walls.

    Also, you will want to install the insulation stop around the chimney/vent that Bob H. referred to, and you will need to insulate the top of the fireblocking too.

    Also, as Bob H. stated in the previous post, install an insulation baffle/stop around the inside of that area at the top so no insulation falls down inside it and collects around the chimney/vent.

    Jerry Peck, Construction / Litigation Consultant
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  39. #39
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    Default Re: Chimney flue firestopping

    Hi,

    My Name is Larry Carlson. I'm a fire origin and cause investigator not a building inspector. I just discovered this site and it's a great resource.

    I am involved in a case where a drywaller is being sued because the draft stop he installed did not provide enough air space between the drywall and the flue. The suit claims that there should have been at least a 1 1/2" space all the way around the flue. The arguement made by the plaintiffs is essentially that the 1" space between the flue and the drywall was insuffecient to allow proper air flow and caused the wood structural members to become too dry, thus contributing to the fire cause or fire spread. I know this sounds ludicrous but thats what their suing for. The buliding inspectors for this home required the drywall installer to cut the drywall 1" away from the flue. I assume this separation has to do with the inspector considering the paper on the drywall as a combustible. I don't see the logic of requiring a draftstop then requiring a 1" gap to be provided all the way around the flue.

    Am I wrong in my conclusion that the draftstop ceased to be a draftstop as soon as the 1" space was opened around the flue?

    I'd appreciate you comments on this issue.

    Larry C.


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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Larry Carlson View Post
    The suit claims that there should have been at least a 1 1/2" space all the way around the flue. The arguement made by the plaintiffs is essentially that the 1" space between the flue and the drywall was insuffecient ...
    Larry,

    All you need to do is find the brand of the vent, and the clearance required in its listing and labeling - both should be on the vent itself.

    As long as the drywall installed allowed at least that much clearance, and the drywall installer could have allowed *exactly* that much clearance, it is out of the hands of the drywall installer and back to the manufacturer of the vent.

    If someone wants to claim that a vent listed for 1 inch clearance "needs to have" greater clearance - that person needs to go after the manufacturer and the testing lab which did the testing, and all other brands of vents and all other testing labs, and all standards as all vents of the same type are listed to the same standard.

    Any one can sue any one else for anything, however, if the suit is over a listed item installed and used in accordance with its listing, then deeper pockets and higher ups need to be named in the action and leave the installer out of it (presuming the installer met the installation requirements - if not, the drywall installer is in deep doo-doo).

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    Cool unfriendly fire

    Larry, I agree w/ Jerry that your case hinges upon the listed instructions of the chimney or vent but I would add the appliance listing, too. If the unit and venting were installed in accordance with the mfr.s listed instructions AND the building code, then it really takes an outside factor to cause ignition at listed firestops. Speaking of which, some terminology needs to get clarified:
    draftstops are used within the structure to restrict air movement. What it sounds like you have is a place where there should be a listed firestop( component of the venting with a listing sticker) and fireblocking per your code, such as R602.8 in the IRC. I understand Calif. was under Ch. 38 of the UBC for the longest time so you'll need to do some research to determine what applied at the time of construction.

    If the point of origin was indeed determined to be at the firestop/ fireblock area and the listed firestop and fireblock were missing then this would probably need to be settled since the proximate cause would be the breech of the duty to install to the listing and codes. Also, you need to rule out other factors such as fall down or unsupported insulation falling down on the firestop thus raising temps., causing pyrolysis and then subsequent ignition. Also, if proper fireblocking was not installed including vertical fireblocking, then the spread of the fire would be comparative negigence for the extension of the fire.

    Larry, you have the leading fireplace investigator in the country right in Moopark, Ca. in Dale Feb. See the FIRE Service links on this site.

    HTH,
    Bob

    Keep the fire in the fireplace.

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    Smile Re: Chimney flue firestopping

    California Home Inspectors need to consult Chapter 7 in the 2007 California Building Code, which by the way, is the longest chapter in the CBC, 86 pages and Chapter 23 Wood, is a runner up at 78. Pay particular attention to Sections 707, 717.1 to 717.4.
    Also, check 2405.5 framing around flues & chimneys and my attachment. House fires are the single biggest reason why codes where written and adopted. Today’s question: Who wrote the first bldg code in the US that was eventually adopted nationwide? JP & BH, keep still …….

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  43. #43
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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Jerry Peck View Post
    From the 2006 IRC. (underlining is mine)

    - R502.13 Fireblocking required.
    Fireblocking shall be provided in accordance with Section R602.8.

    - R602.8 Fireblocking required.


    Fireblocking shall be provided to cut off all concealed draft openings (both vertical and horizontal) and to form an effective fire barrier between stories, and between a top story and the roof space. Fireblocking shall be provided in wood-frame construction in the following locations.
    - - 1. In concealed spaces of stud walls and partitions, including furred spaces and parallel rows of studs or staggered studs; as follows:
    - - - 1.1. Vertically at the ceiling and floor levels. (Jerry's note: If the stud space is open on the back side in the attic, it is no longer "concealed space", it is simply "attic space", thus this not apply as this is for "concealed spaces", thus the only location fireblocking is required or needed is the stud cavities at the soffit "ceiling" level. If the wall is covered with gypsum board (for example) over both vertical surfaces all the way to the top plate, the the top part of the stud is a "concealed space". Then the stud cavities would need to have fireblocking installed at the lower "ceiling" (soffit) level AND at the higher ceiling level- because the concealed spaces are required to be fireblocked at "ceiling ... levels".)
    - - - 1.2. Horizontally at intervals not exceeding 10 feet (3048 mm).
    - - 2 At all interconnections between concealed vertical and horizontal spaces such as occur at soffits, drop ceilings and cove ceilings. (Jerry's note: This also requires the fireblocking at the lower soffit level as the walls below have stud cavities which are concealed spaces.)
    - - 3. In concealed spaces between stair stringers at the top and bottom of the run. Enclosed spaces under stairs shall comply with Section R311.2.2.
    - - 4. At openings around vents, pipes, ducts, cables and wires at ceiling and floor level, with an approved material to resist the free passage of flame and products of combustion. (Jerry's note: This section would also apply should there be any wires, piping, ducts, etc., in the stud cavity concealed spaces.)
    - - 5. For the fireblocking of chimneys and fireplaces, see Section R1003.19.
    - - 6. Fireblocking of cornices of a two-family dwelling is required at the line of dwelling unit separation.

    Hopefully, that helps explain the drawing.


    I encountered a couple of circumstances yesterday that appear to relate to #4 above. The draft stop (or fireblocking) at the vertical chimney chase has been penetrated at two locations. One is a CATV cable that descends from the attic through a hole that appears to have been bored by the home owner in order to mount a flat panel TV above the fireplace opening. The hole is rather large and the code reference you've provided above indicates to me that some kind of fitting is needed to provide closure at the gap. The hole seen in the attached photo penetrates the top of the stud wall that forms the face of the fireplace (and one side of the triangular flue chase). Nearby, and directly adjacent to the fireplace flue itself, is a 4-inch flex duct that penetrates the draftstop at the ceiling level. There is also about a 1/2-inch gap at that penetration. Should these penetrations have some type of fitting as seems to be indicated at #4 above?

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  44. #44
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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Jerry Peck View Post
    From the 2006 IRC. (underlining is mine)

    - R502.13 Fireblocking required.
    Fireblocking shall be provided in accordance with Section R602.8.

    - R602.8 Fireblocking required.


    Fireblocking shall be provided to cut off all concealed draft openings (both vertical and horizontal) and to form an effective fire barrier between stories, and between a top story and the roof space. Fireblocking shall be provided in wood-frame construction in the following locations.
    - - 1. In concealed spaces of stud walls and partitions, including furred spaces and parallel rows of studs or staggered studs; as follows:
    - - - 1.1. Vertically at the ceiling and floor levels. (Jerry's note: If the stud space is open on the back side in the attic, it is no longer "concealed space", it is simply "attic space", thus this not apply as this is for "concealed spaces", thus the only location fireblocking is required or needed is the stud cavities at the soffit "ceiling" level. If the wall is covered with gypsum board (for example) over both vertical surfaces all the way to the top plate, the the top part of the stud is a "concealed space". Then the stud cavities would need to have fireblocking installed at the lower "ceiling" (soffit) level AND at the higher ceiling level- because the concealed spaces are required to be fireblocked at "ceiling ... levels".)
    - - - 1.2. Horizontally at intervals not exceeding 10 feet (3048 mm).
    - - 2 At all interconnections between concealed vertical and horizontal spaces such as occur at soffits, drop ceilings and cove ceilings. (Jerry's note: This also requires the fireblocking at the lower soffit level as the walls below have stud cavities which are concealed spaces.)
    - - 3. In concealed spaces between stair stringers at the top and bottom of the run. Enclosed spaces under stairs shall comply with Section R311.2.2.
    - - 4. At openings around vents, pipes, ducts, cables and wires at ceiling and floor level, with an approved material to resist the free passage of flame and products of combustion. (Jerry's note: This section would also apply should there be any wires, piping, ducts, etc., in the stud cavity concealed spaces.)
    - - 5. For the fireblocking of chimneys and fireplaces, see Section R1003.19.
    - - 6. Fireblocking of cornices of a two-family dwelling is required at the line of dwelling unit separation.

    Hopefully, that helps explain the drawing.

    This does not relate to a chimney flue chase, but I did find what appears to be a concealed vertical space that is open to the attic. This is essentially a fur down above a triangular area framed in a corner of a hallway that has drywall sheathed shelving for display of objects de art. It appears to be about 2-1/2 feet deep. Shouldn't this be fireblocked at the ceiling level?

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    Default Re: Chimney flue firestopping

    Robert,

    I seem to recall something about nothing except a chimney flue pipe in a chase. This would be from a few months ago. You would have to do a search in the fireplace section.

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    Default Re: Chimney flue firestopping

    Robert,

    See answers on other forum where you posted those duplicate items.

    Makes for confusing things to duplicate post them.

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  47. #47
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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Jerry Peck View Post
    Robert,

    See answers on other forum where you posted those duplicate items.

    Makes for confusing things to duplicate post them.
    Sorry. This thread was so old I was worried I might not get a response. And, by the way, thanks for the responses at the other thread.


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    Default Re: Chimney flue firestopping

    I know this is an old thread but I am having an issue while trying to sell my house. An inspector made a note on a picture in a report for the buyer that says "seal top of chimney chase". This is a two story house and there is an opening from the chimney cahse into the attic abobe the second floor. The chimney and chase run up the side of the house on teh exterior. There is a "firebreak" that is down inside the chase at the level that is between the first and second floor. Is there a requiremet to have a firebreak or for there to be insulation at the second floor celing level? And does anyone know what bart insulation is?

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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Chuck McInturff View Post
    This is a two story house and there is an opening from the chimney cahse into the attic abobe the second floor. The chimney and chase run up the side of the house on teh exterior. There is a "firebreak" that is down inside the chase at the level that is between the first and second floor. Is there a requiremet to have a firebreak or for there to be insulation at the second floor celing level? And does anyone know what bart insulation is?
    Not quite following you as what I read in your post and the photos are not matching, either that or I am not reading what you wrote correctly ... be that as it may be ...

    "Fireblocking" is required at the following locations:
    - any and all concealed combustible (wood) framed or furred spaces
    - at the floor level of the first floor
    - if there is a basement with a finished ceiling, at the basement ceiling level
    - at the ceiling level of the first floor
    - at the floor level of the second floor
    - at the ceiling level of the second floor

    I am presuming that the chimney runs all the way from the lowest floor (first floor or basement if present) through the attic to, and through/above the roof.

    If you imagine the chase is a tall box, the inside of that tall box needs to be fireblocked at each floor level and each ceiling level.

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    Last edited by Jerry Peck; 05-22-2013 at 06:27 PM. Reason: added drawing
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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Jerry Peck View Post
    Not quite following you as what I read in your post and the photos are not matching, either that or I am not reading what you wrote correctly ... be that as it may be ...

    "Fireblocking" is required at the following locations:
    - any and all concealed combustible (wood) framed or furred spaces
    - at the floor level of the first floor
    - if there is a basement with a finished ceiling, at the basement ceiling level
    - at the ceiling level of the first floor
    - at the floor level of the second floor
    - at the ceiling level of the second floor

    I am presuming that the chimney runs all the way from the lowest floor (first floor or basement if present) through the attic to, and through/above the roof.

    If you imagine the chase is a tall box, the inside of that tall box needs to be fireblocked at each floor level and each ceiling level.
    Thanks for your response Jerry. Your drawing is an accurate representation (without the basement) of the house and the chimney which is on the outside of the house. The drawing that was attached was what the inspector sent and I added (in red) where the existing firebreak is. Is this requirement something that changed after 2003-2004 when the (my) house was was built or could this be something that was not done correctly at the time of construction and installation of the chimney? This was his response directly to me after a bunch of back and forth emails between me and my agent and the buyers agent and the inspector,

    "If you can see the bare walls below and the top of the firebox then you need to seal the chase at the top where it comes into the attic or insulate all the bare walls.

    BATT insulation is what you show in your pictures."

    I am attaching the picture I sent them showing the firebreak at the floor level of the second floor. In the other picture I am attaching I drew in the area that according to your drawing should be closed off, is there a specific requirement on what that is supposed to be i.e. material, material thickness etc.? Oh, and the inspectors drawing is just a representation of the second floor , I guess.

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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Chuck McInturff View Post
    Is this requirement something that changed after 2003-2004 when the (my) house was was built or could this be something that was not done correctly at the time of construction and installation of the chimney?
    These requirements go way back in time ... w-a-y b-a-c-k in time. Looks like your house was not done correctly at the time of construction and installation of the chimney.

    This was his response directly to me after a bunch of back and forth emails between me and my agent and the buyers agent and the inspector,

    "If you can see the bare walls below and the top of the firebox then you need to seal the chase at the top where it comes into the attic or insulate all the bare walls.
    He is partially correct ... but only partially correct - the chimney needs to be fireblocked at each of the levels in my drawing, not just "at the top where it comes into the attic".

    Additionally, the walls of the chimney need to be insulated, and that insulation (and anything else) needs to be removed off the top of the firebox.

    ... is there a specific requirement on what that is supposed to be i.e. material, material thickness etc.?
    The fireblocking should be one of the following:
    - 2x lumber
    - 2 layers of 1x lumber
    - 3/4” structural panels (i.e., plywood or OSB)
    - 3/4” particle board (I would avoid like the plague - particle board is simply not much good for anything other than shelves - and not much good for that either)
    - 1/2” drywall
    - 1/4” cement board
    - fiberglass/mineral wool batts - while this may seem like the easy way out, using this is not 'just stuffing it down in there and hoping it stays in place', using this means that you make sure it will stay in place *forever* (or at least the life of the house), and if you've ever tried to make sure that batt insulation stays in place you will realize that it would be easier to to use plywood or drywall instead

    Which ever material is used, it is to be tight fitting and sealed around, not with that expanding foam you would normally buy at one of the Big Box stores but the expanding foam type which states right on the can that it is approved for "Fireblocking", it is usually a reddish/orangish/pinkish colored foam, not the cream colored you usually see used around windows, doors, and other places to seal gaps.

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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Jerry Peck View Post
    These requirements go way back in time ... w-a-y b-a-c-k in time. Looks like your house was not done correctly at the time of construction and installation of the chimney.



    He is partially correct ... but only partially correct - the chimney needs to be fireblocked at each of the levels in my drawing, not just "at the top where it comes into the attic".

    Additionally, the walls of the chimney need to be insulated, and that insulation (and anything else) needs to be removed off the top of the firebox.



    The fireblocking should be one of the following:
    - 2x lumber
    - 2 layers of 1x lumber
    - 3/4” structural panels (i.e., plywood or OSB)
    - 3/4” particle board (I would avoid like the plague - particle board is simply not much good for anything other than shelves - and not much good for that either)
    - 1/2” drywall
    - 1/4” cement board
    - fiberglass/mineral wool batts - while this may seem like the easy way out, using this is not 'just stuffing it down in there and hoping it stays in place', using this means that you make sure it will stay in place *forever* (or at least the life of the house), and if you've ever tried to make sure that batt insulation stays in place you will realize that it would be easier to to use plywood or drywall instead

    Which ever material is used, it is to be tight fitting and sealed around, not with that expanding foam you would normally buy at one of the Big Box stores but the expanding foam type which states right on the can that it is approved for "Fireblocking", it is usually a reddish/orangish/pinkish colored foam, not the cream colored you usually see used around windows, doors, and other places to seal gaps.
    Again, thank you very much for your response Jerry. I have recieved more of a response and explination here in just a few hours than I have gotten from the buyers agent/buyers inspector. So if I were to do this myself I would need to insulate the other three walls of the chase (with BATT?) and I could build a sort of lattice at the celing level of the second level of the house and lay BATT over the lattice in a way that seals everything off at that level? Or insulate the three walls of the chase and build some sort of deck that seals that area and use the fireblock foam to seal any openings not covered by the deck? I don't believe the "deck" at the bottom of the picture is the firebox, I think that is at the floor level of the second floor, I could be wrong though and can remove the insulation that appears to have fallen off of the back of the interior wall. And just so I am unserstanding correctly, this all applies even though the flue from the firepalce never passes through any floor or celing inside the house, it is all in an enclosed "box" on the exterior of the home with a brick veneer.

    Last edited by Chuck McInturff; 05-22-2013 at 09:09 PM. Reason: Added question for clarification

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    Default Re: Chimney flue firestopping

    Quote Originally Posted by Chuck McInturff View Post
    So if I were to do this myself I would need to insulate the other three walls of the chase (with BATT?) ...
    Yes, and use unfaced batt insulation with strapping to hold it in place to the exterior walls (the OSB walls in your photo) of the chase.

    ... and I could build a sort of lattice at the celing level of the second level of the house and lay BATT over the lattice in a way that seals everything off at that level?
    At the first floor ceiling-level ... and at the second floor floor-level ... and at the second floor ceiling-level. You need to either install the fireblocking at the three separate locations, or you can install the batt insulation from the first-floor ceiling level, layered thick enough to fully pack and fill the space to the second floor floor-level, effectively creating two separate locations for the fireblocking yet fulfilling the the requirement for fireblocking at each floor level and each ceiling level. The latter may be easier, but it will require even stronger supports for all that insulation. If your second floor floor-trusses are 24" deep then you would need to pack the insulation 24" deep. Oh, one more thing, you would also need to install listed fireblock devices around the chimney at each level to serve as fireblocking at each level as the insulation you will be packing in there will need to be at least 1" clearance from the metal chimney and possibly as much as 3" clearance (there should be stickers on the metal chimney stating the minimum clearance.

    And, if you were to use wood, the wood would need to be at least 2" minimum clearance from the chimney, so you would still need three of the listed fireblock pieces for that chimney.

    The lattice would need to be of material which would not burn and allow the batt insulation to drop out of place, i.e., no string, no thin lattice wood, etc. - the lattice would need to survive the fire long enough for the insulation to stay in place, think of the time it would take to burn through 3/4" plywood.

    The wall with drywall on in your photo is the interior wall of the house. One strip of insulation is still in place, the others have either fallen down (attesting to what I am saying about keeping the insulation in place 'forever') or was not installed.

    The more detail I try to lay out, the more complicate you will see it to be, such as the clearances to combustible and insulation from the metal chimney.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

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