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  1. #1

    Default Roof rafter framing

    Hello all,

    In an inspection the other day I found this roof framing that was of concern to me. My concern was that the valley rafter beam was not fully on the ridge beam where they were connected together. In the first photo you can see that only about half of the width of the end of the valley rafter beam is in contact with the homes main ridge beam. There were no obvious structural issues with the roof, but Iím wondering if at least some sort of structural fastener should be installed here to ensure that they would never slide apart? Also, I include a picture of the front of the home so that you may see the roof configuration. The area of concern is in the front right corner of the main house roof and noted the location with the red circle.

    Thanks.

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  2. #2
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    Default Re: Roof rafter framing

    I don't like to punt but I would write it up for an SE report. There's so much going on there. If something goes wrong it's going to go really wrong. It looks like they clearly had the B team doing the framing. Rather disturbing if some muni insp signed off on it.
    The lack of full bearing is not only present at the engineered beams you are pointing out but also all the regular rafters shown in the pics.
    The ridge beam looks to be the same size as the rafters. The ridge should be one size up so that the rafters have full support due to the additional length of the rafter end from the angle cut.
    Even though this is new construction, some of the pieces look like old growth lumber. Maybe that's just the coloring in the pic though.
    That ridge section was clearly just thrown together with scraps.
    From my experience with Plans, the two rafters (one on each side of the roof plane) directly to the right of the beams would typically be doubled up or also engineered since this is a major bearing point.
    Can't tell to well from the pics but lack of nailing also seems to be an issue.

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  3. #3

    Default Re: Roof rafter framing

    Thanks Marcus. I am with you I hate to punt too but there is just so much going on in this location. I will write it up accordingly. Your other points regarding size of ridge beam, doubling of rafters to the sides of beam and nailing are well taken.


  4. #4
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    Default Re: Roof rafter framing

    Actually there is no beam in that roof, only ridge boards. The bearing points are wrong and inadequate. That's not to say that the roof is going to fail but I wouldn't say that there's no reason to say that it won't. A qualified framer should be able to make the necessary repairs. What it might cost I wouldn't even touch.

    Eric Barker, ACI
    Lake Barrington, IL

  5. #5
    James Duffin's Avatar
    James Duffin Guest

    Default Re: Roof rafter framing

    For what it's worth in the conversation, in NC you don't have to have a ridge board as long as the rafter ends meet.


    R802.3 Framing details.
    Rafters shall be framed to ridge
    board or to each other with a gusset plate as a tie. Ridge board
    shall be at least I-inch (25 mm) nominal thickness and not less
    in depth than the cut end of the rafter. At all valleys and hips
    there shall be a valley or hip rafter not less than 2-inch (51 mm)
    nominal thickness and not less in depth than the cut end of the
    rafter. Hip and valley rafters shall be supported at the ridge by a
    brace to a bearing partition or be designed to carry and distribute
    the specific load at that point. Where the roof pitch is less
    than three units vertical in 12 units horizontal (25-percent
    slope), structural members that support rafters and ceiling
    joists, such as ridge beams, hips and valleys, shall be designed
    as beams.



    Last edited by James Duffin; 05-01-2011 at 07:14 PM.

  6. #6
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    Default Re: Roof rafter framing

    Eric is correct, that is a simple ridge board. It is not supported from below. The opposing rafters hold it up.
    The steep pitch, 12 in 12 I think, makes for a pretty strong roof design, not one that is likely to sag under a load of snow, for example. I suspect there may be a flat section on top, but it is not significant in size compared to the sloped portions. ( I've inspected similar designs before. You see a steep slope and think that's all of it, but the top of the cone has to have that flat portion to span to the back roof sections )

    The ridge board looks like it is needed here to catch the tops of those valley rafters. You are right, the ridge boards need to be full width, usually one size wider than the rafters.
    I would call for repair by a qualified builder. Ridge boards too narrow. Ensure proper nailing of the rafter ties. Have the rest of the structure checked out as well.

    Last edited by John Kogel; 05-01-2011 at 09:17 PM.
    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

  7. #7
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    Default Re: Roof rafter framing

    The framer needs to make the following repairs......first....common rafters need full support at the ridge so a board can be attached properly under the existing ridge. Second.... long spans of rafters need proper bracing to prevent deflection. Third ..... a support is needed under the common junction of the hip,valley,common rafter intersection at the top. Fourth....collar ties need to be in the upper third......it looks a little low to me...... I hope this helps.


  8. #8
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    Default Re: Roof rafter framing

    Scott

    Without looking at the entire roof system my comments will be limited to your pictures. With that steep roof snow loading would not be my first concert, wind load will most likely be the critical force to deal with. Those engineered beams will have a significant horizontal thrust component and I don't see anything on the opposite side that is going to support or resist those forces. Most roofs and this house is no exception must be analyzed as a complete system. Many roofs by their construction have some level of redundancy or excess capacity of other roof framing members to reduce the impact of any one component failure. This complex roof system, depending upon how many other framing issues there are, would most likely require a computer model of the entire roof system with wind loads applied to see what forces we are dealing with. Typically you will find the individual members, beams, rafters and joists are not the problem. Its the connections that are usually the weakest link. For example that engineered beam probably has plenty of excess capacity to support the load but the nails it was attached with is the weak point. Ultimate failure will be the nails pulling out and not the beam breaking.

    Randy Mayo, P.E.
    Residential Engineering & Inspection Services
    http://www.rlmengineers.com

  9. #9
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    Default Re: Roof rafter framing

    whats up with the sunlight coming through at the peak?


  10. #10

    Default Re: Roof rafter framing

    I keep looking at that architectural detail of the offset slopes and wondering if it was really worth it? Two extra LVL's, all the additional framing time, adding a hip and valley to shingle (and the accompanying extra material. I would rather have spent that money upgrades to the man cave!

    Just because you can design it does not mean you should!

    Egbert Jager
    Diamond Home Inspection
    http://www.diamondhomeinspection.ca

  11. #11
    Terry Griffin's Avatar
    Terry Griffin Guest

    Default Re: Roof rafter framing

    I agree with Marcus and Eric. Call in an SE and put the liability on someone else. You will have fulfilled your duty to report it.


  12. #12
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    Default Re: Roof rafter framing

    How do you spell amateur?
    A SE is required for a full & thorough evaluation of the roof framing support system.

    Jerry McCarthy
    Building Code/ Construction Consultant

  13. #13

    Default Re: Roof rafter framing

    Thanks guys for all your replies. I recommended having it further evaluated by a SE or other qualified structural contractor (i.e., qualified framing roofer). Needless to say the realtor was not very pleased and she said that builder has built at least 10 other homes like that design. Still waiting for the outcome. Will try to keep yunz posted.


  14. #14
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    Default Re: Roof rafter framing

    "Needless to say the realtor was not very pleased and she said that builder has built at least 10 other homes like that design."

    Thats when you say:
    Good, now he knows not to build anymore like that.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  15. #15
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    Default Re: Roof rafter framing

    I wonder if the blueprint is available? It'd be interesting to see if this build is on that print.


  16. #16

    Wink Re: Roof rafter framing

    Quote Originally Posted by Rick Cantrell View Post
    "Needless to say the realtor was not very pleased and she said that builder has built at least 10 other homes like that design."

    Thats when you say:
    Good, now he knows not to build anymore like that.
    That is funny. I will remember that one.


  17. #17
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    Default Re: Roof rafter framing

    I kinda thought you would like that.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

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