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  1. #1
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    Default Fire rated eave overhang?

    In the more for less dept...
    A builder we do business with is putting 45' wide house on a 50' lot and therefore has only 5' clear space on each side. He was told that the walls would need to have a fire resistive construction, and also the eave overhang would need to be rated 1 hour as well because it encroaches into the setback. The detail he gave us (one coat stucco sub) shows 2 layers of type X screwed into the rafter tails(3-5/8") with lath and stucco over that. The wood fascia and 1X trim piece are to be left exposed, according to the detail. My question is: Is the assembly considered rated if the fascia board is left exposed? The roof is to be tile, like most are in this area, over felt and 15/32" sheathing.
    Any comments? Please Jerry-no snide comments about whether or not this is stucco, just address the question if you can.

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    Default Re: Fire rated eave overhang?

    Quote Originally Posted by John Carroll View Post
    In the more for less dept...
    A builder we do business with is putting 45' wide house on a 50' lot and therefore has only 5' clear space on each side. He was told that the walls would need to have a fire resistive construction, and also the eave overhang would need to be rated 1 hour as well because it encroaches into the setback.
    And any windows in those walls too. I can see *that* as being a big problem, unless there are rooms on the sides of the house which do not require natural light and ventilation.

    The detail he gave us (one coat stucco sub) shows 2 layers of type X screwed into the rafter tails(3-5/8") with lath and stucco over that. The wood fascia and 1X trim piece are to be left exposed, according to the detail. My question is: Is the assembly considered rated if the fascia board is left exposed?
    I'm not sure the assembly is 'rated' anyway. The must be a UL Fire Resistance Deign Number for whatever system is used.

    Two things come into play here:
    1) Fire from the outside (the house next door).
    2) Fire from within to the outside (toward the house next door).

    The Type X would need to be on each side of the "fire rated assembly", i.e., the exterior side and the interior side and the attic side, and, any penetrations in that fire rated assembly would require opening protectives based on the opening size. This includes electrical boxes in that to-be-fire-rated-wall assembly (within the requirements for electrical boxes in fire rated walls), this also means no soffit vents on those sides, and don't forget to protect the underside of the roof sheathing with Type X, or use Fire Retardant Treated roof sheathing, for the first 4 feet back from the fire rated wall and over the overhang.

    I'd recommend a re-design such that there is 'no overhang' and there really is no purpose for it, it cannot be used for soffit venting, and it just creates liabilities, I'd recommend just running the wall (the fire rated assembly wall) straight up to the roof decking and sticking on a decorative trim.

    The roof is to be tile, like most are in this area, over felt and 15/32" sheathing.

    Any comments? Please Jerry-no snide comments about whether or not this is stucco, just address the question if you can.
    It does not matter what that is called, it only matters whether or not it is approved as part of the fire rated wall system, or, whether it is applied in addition to (as an extra above and beyond) the requirements for the fire rated wall assembly. If it is 'part of' the fire resistive rated wall assembly, it must be *as specified* in the fire resistive design for that wall section.

    There are too many variations available to even attempt to go into them here.

    The thing to remember for *any* fire rated wall, though, is that 'the fire could start on either side of it', thus, attaching two layers of Type X to the exterior does no good if the fire starts inside the house.

    This is what the IBC states: (underlining is mine)
    704.5 Fire-resistance ratings.
    Exterior walls shall be fire-resistance rated in accordance with Tables 601 and 602. The fire-resistance rating of exterior walls with a fire separation distance of greater than 5 feet (1524 mm) shall be rated for exposure to fire from the inside. The fire-resistance rating of exterior walls with a fire separation distance of 5 feet (1524 mm)or less shall be rated for exposure to fire from both sides.



    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Fire rated eave overhang?

    The UBC note listed on the detail is from IBC Table 720.1 (3). Here is the detail.RATED EAVE DETAIL.jpg


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    Angry Re: Fire rated eave overhang?

    Windows, doors, vents, roof covering - hell any opeing will be either fire-rated or not allowed. See Jerry' P's post.

    And, a 45 foot width home on a 50 foot wide lot leaves 2-1/2 foot set-back on each side. I'm surprised the local zoning would allow and in particular the fire mashall? Where I'm from 6 feet is usually minimum side set-back and that's for cluster homes, of which I have another name for.

    Jerry McCarthy
    Building Code/ Construction Consultant

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    Default Re: Fire rated eave overhang?

    In South Florida, the norm for the past 20+ years has been for Zero Lot Line homes, where the side of the house is on one lot line (the zero lot line side) and the other side has 10 feet to the property line.

    The houses are 10 feet apart from house-to-house, but each is also on its lot line on one side. Hope you have friendly neighbors.

    I raised the 'maintenance' issue many years ago when inspecting some of those home and now many of those Zero Lot Line subdivisions now have a 2' or 3' easement on the zero lot line side which will allow the homeowner to maintain that side of their home. Otherwise, how could you paint the side of your home if the property you had to stand on belonged to an irate neighbor who refused to let you on their property (their right if there is no maintenance easement recorded).

    Which brings up another problem ... take those zero lot line home, with all fenced in rear yards, and stick them back-to-back-to-back with no way out of those yards (some did not have gates from the rear yard). One local Fire Chief I asked about that and how they would rescue persons trapped back there, he thought a few seconds and said 'I don't recall seeing a fence I could not take down with a fire truck ... the fence would not be a problem for us.'

    I would relay that information to my clients buying those homes. You should have seen the looks on their faces when I explained, while standing in the rear yard, where they would need to retreat to from a fire, and not to stand near the fence - just in case the fire truck came crashing through.

    'Ah, er, if I can't stand back at the fence for fear of being run over by the fire truck, then I have to stand up near the house ... which is on fire, right?'

    'Yes, that's about right', would be my reply.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Fire rated eave overhang?

    According to the IBC reference used, the eave assembly as detailed, is in conformance with the code, with the exception of the exposed wood 2 X 6 fascia board which is not addressed in the reference.

    Since the minimum requirement on the top side of this assembly is 1/2" "structural wood panels", I would think the 1-5/8" wood would be sufficient at the end of the assembly, but I have nothing to confirm that from the assembly detail given.

    I believe the intent here is to slow the combustion of the eave from a fire outside the structure, rather than keeping the a fire within the structure from spreading. After all, any fire that makes it to that part of the roof would already have involved the sheathing considerably by then.

    For this discusssion, assume that all other walls, penetrations, electrical boxes, service panels are constructed as necessessary to conform to the code and focus on the fascia board issue. Is that portion of the eave considered an acceptable termination for the IBC assembly detail given?


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    Default Re: Fire rated eave overhang?

    Quote Originally Posted by John Carroll View Post
    I believe the intent here is to slow the combustion of the eave from a fire outside the structure, rather than keeping the a fire within the structure from spreading.
    NOT according to the code section I posted above, which this quote is from "The fire-resistance rating of exterior walls with a fire separation distance of greater than 5 feet (1524 mm) shall be rated for exposure to fire from the inside. The fire-resistance rating of exterior walls with a fire separation distance of 5 feet (1524 mm)or less shall be rated for exposure to fire from both sides."

    Not sure what you are missing in that.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Fire rated eave overhang?

    What you're missing is that we are not talking about the WALLS. The Code reference applies to floors & roof systems.

    Forget about the WALLS! The walls are rated.

    I need an answer about the EAVE assembly.

    JEEZ, try to focus here, Jerry...


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    Default Re: Fire rated eave overhang?

    Quote Originally Posted by John Carroll View Post
    JEEZ, try to focus here, Jerry...
    T-h-e f-i-r-e r-a-t-e-d *W-A-L-L* n-e-e-d-s t-o continue to the underside of the roof deck and the roof deck needs to be protected.

    Did I go slow enough for you John.

    Until you get to the roof deck, you are STILL talking about WALLS.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Fire rated eave overhang?

    You're right, of course, the details they gave us do not show it, but the type X extends to the bottom of the roof sheathing, so the wall is protected.

    The question remains, what about the eave assembly?
    Is the IBC call out, 720.1 (3) the wrong application for this condition or what?


  11. #11
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    Default Re: Fire rated eave overhang?

    John,

    Do you have a better quality drawing, one of higher resolution? I can't read anything on that one.

    Which number in Table 720.1(3) would you be referring to?

    I would think that a small overhang, fully enclosed (no vents), on the outboard side of a fire rated wall, with the roof decking protected as required ... would not be a problem. How small is "a small" overhang and what constitute a "large" overhang, I'm not sure. And I can't tell what is indicated/implied in that drawing.

    Also, is the house 5 feet, greater than 5 feet, less than 5 feet, from the property line to the wall? If, as Jerry M. said, there is only 2-1/2 feet from the wall to the property line, things will need to be a lot more critical than if the wall was at or just over 5 feet from the property line.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Fire rated eave overhang?

    I'm sorry about the quality of the scanned detail... the overhang is less that 1' 2" in either case shown. The roof sheathing , of course, would need to be rated to 4'-0" from the edge of roof, or outside edge of plate line?? (Not sure here.)

    My question was in regard to the exposed fascia board. Would it need to be fire resistant lumber? I would assume so, but it is not addressed by the IBC call out given...
    Sorry about the sarcastic tone, but you started it...


  13. #13
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    Default Re: Fire rated eave overhang?

    Quote Originally Posted by John Carroll View Post
    I'm sorry about the quality of the scanned detail... the overhang is less that 1' 2" in either case shown. The roof sheathing , of course, would need to be rated to 4'-0" from the edge of roof, or outside edge of plate line?? (Not sure here.)
    4 feet from each side of the fire wall (not from center, from each side), to the end of the roof on the overhang side.

    My question was in regard to the exposed fascia board. Would it need to be fire resistant lumber? I would assume so, but it is not addressed by the IBC call out given...
    Being as that house is most likely Type V construction, wood should be acceptable as Type V construction is, basically, 'anything goes'.

    Sorry about the sarcastic tone, but you started it...
    Did not.

    Jerry Peck, Construction / Litigation Consultant
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  14. #14
    Robert Koch's Avatar
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    Default Re: Fire rated eave overhang?

    You may have some difficulty applying the IBC at all. As Jerry said earlier - get a UL number and go to their reference materials. Have their architect specify the rated assembly.

    Bob


  15. #15
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    Default Re: Fire rated eave overhang?

    Quote Originally Posted by John Carroll View Post
    The UBC note listed on the detail is from IBC Table 720.1 (3). Here is the detail.RATED EAVE DETAIL.jpg
    I'm very interested in locating the book from which this scan is made. Could you please help with a title and author? Or perhaps aim me at a higher resolution version?


  16. #16
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    Default Re: Fire rated eave overhang?

    It was not a book, but a set of plans. I cropped it to remove any identifying features to avoid copywrite infringment issues. Sorry.

    I'm a dyslexic agnostic-Don't believe there is a dog...

  17. #17
    Rod Marusic's Avatar
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    Default Re: Fire rated eave overhang?

    Hi John;
    If you are looking for eave vents that resist flame and ember intrusion, you might want to take a quick look at this product. It just got accepted for use in CA by the CSFM (California State Fire Marshal)
    FireGuardVent by Vivico LLC auto/manual ember and fire intrusion resistant vent, Accepted by the California State Fire Marshal, tested by CA state approved lab.
    Good luck...
    Rod


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