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Thread: Rafter splicing

  1. #1
    Richard Rushing's Avatar
    Richard Rushing Guest

    Default Rafter splicing

    Anyone have much feedback on the V/notch single tongue-n-groove method of splicing rafters together?

    I just don't ever see these and was wondering about what the determining factor as to when to use this method, would be... The roof was an 10/12 pitch.

    Normally, I would think that if this method were used, there would be a scab of OSB across at least one, and possibly both sides of the rafter lagged together across the splice.

    Opinions welcome...

    Rich

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  2. #2
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    Default Re: Rafter splicing

    My understanding is that you cannot splice rafters when steel rafters are used. (2006 IRC 804.3.7) No exceptions are given.

    When the roof structure is wood, I did not find where splicing is directly addressed. However, cutting and notching of rafters is addressed. (2006 IRC R802.7.) The next section (R802.7.1) addresses sawn rafters and says in part (bold is mine)

    " Notches in the ends of members shall not exceed one forth of the depth of the member. The tension side of the members 4 inches (102mm) or greater in nominal thickness shall not be notched except at the ends of the members."

    Usually when I see the pictured splicing, it has a run of 2x2 nailed beneath the rafter splice and no brace to bearing. Length of the notches and the "bracing", as the builder calls the 2x2 vary.

    Life is easier for me. 95% of my work is in a hurricane zone. Splicing of roof members is permitted, but specific methods are dictated. A splice clearly is right or wrong. In this hurricane zone the splice will have 1/2 inch or better Plywood or OSB scabs on each side and a designed patten of 21 nails per side through each side. The scabs must extend two feet, minimum, both directions from the splice. Bracing to bearing must be placed as close to the splice as possible and cannot be less than 45* from th horizontal.

    Almost all splices are butt cuts so that the scab lengths can be the minimum 4 feet. The brace to bearing provision was added in 2003, I believe.

    I have to back out today, si I didn't have time to search for a rafter spilce. Here's a picture of a hip splice. The rafter would be spliced the same way.

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  3. #3
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    Default Re: Rafter splicing

    That looks like what a master carpenter friend of mine called a scarf(sp?) joint. Traditional splice when lumber is not available in the length needed. I know there were limitations on where and when he would use them, but I can't recall those details. Full length lumber is preferred, but sometimes you just can't get a 60' 2"x8" or what ever.

    Jim Luttrall
    www.MrInspector.net
    Dallas, Texas

  4. #4
    Richard Rushing's Avatar
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    Default Re: Rafter splicing

    Any more thoughts... comments...


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    Default Re: Rafter splicing

    Quote Originally Posted by Richard Rushing View Post
    Any more thoughts... comments...
    Today, that would be referred to as "end jointed lumber".

    From the IRC.
    - R802.1.2 End-jointed lumber. Approved end-jointed lumber identified by a grade mark conforming to Section R802.1 may be used interchangeably with solid-sawn members of the same species and grade.


    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Rafter splicing

    Richard,

    For what it's worth, here in Austin I often see that splice configuration but it always has OSB sheathed at either side of the splice, a 2x2 below the spice and is supported to a bearing wall with a stiff leg. The B.O.s around here never red tag it done as I (and Thom) have described it (as far as I have seen, and I have shown up for pre drywall inspections right after the B.O. finished his rough) and I see it mainly at hip or valley rafters on many of the new construction and one year old homes that I have inspected. I saw two today on two different properties.

    When I do not see all of the components listed above at a spliced rafter I recommend evaluation and I have never gotten a nasty call back about the rec. (not that it means anything). I have yet to find a direct reference to wooden rafter "splices" in IRC.

    Eric


  7. #7
    Richard Stanley's Avatar
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    Default Re: Rafter splicing

    IRC 802.7 Structural roof members (rafters) shall not be cut etc., etc.,
    IRC 804.3.7 Rafters .... shall not be spliced. When I see it, its referred to a PE.
    I have, however, seen the splice in Thoms pic, prescribed and documented, by a PE. I would not take it upon myself to recommend that fix nor assume that the same one in another setting would be the correct one.


  8. #8
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    Default Re: Rafter splicing

    Quote Originally Posted by Richard Stanley View Post
    IRC 802.7 Structural roof members (rafters) shall not be cut etc., etc.,
    IRC 804.3.7 Rafters .... shall not be spliced. When I see it, its referred to a PE.
    I have, however, seen the splice in Thoms pic, prescribed and documented, by a PE. I would not take it upon myself to recommend that fix nor assume that the same one in another setting would be the correct one.

    Rick,

    IRC, R802.7 Cutting and notching. Structural roof members shall
    not be cut, bored or notched in excess of the limitations specified
    in this section.

    This section refers to wood, and one could think of that as a cut or notched piece, cut or notched all the way through. Either way, it is now "end jointed" (the ends are joined), 'spliced' if you prefer.

    IRC, SECTION R804, STEEL ROOF FRAMING ...

    That section refers to steel roof framing only, as Thom pointed out, thus it is not applicable to wood roof framing.

    To me, recommending a structure engineer (not just a PE) to "design appropriate repairs" would be the recommended way to address this. *IF* the structural engineer come back and says 'no repair needed', that is still what you recommended, it is the 'appropriate' repair.


    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Rafter splicing

    I have always considered "end jointed" lumber to mean finger jointed with adhesives at the joints. ICC and the American Wood Council also refer to end jointed as finger jointed with adhesive. Would this type of rafter splice actually be consisdered end jointed? Any thoughts?

    Thanks,
    Eric


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    Default Re: Rafter splicing

    Jerry, I think that it would be a stretch to call that "end Jointed lumber" which would be grade marked by the manufacturer. I think the intent of the code in R802.1.2 is pretty clear that it is NOT field joined lumber, but factory produced and graded like the lumber in R802.1.

    Jim Luttrall
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    Default Re: Rafter splicing

    It's a confusing subject in Texas. Until 2003, we had a separate and enforceable windstorm code. The method of splice described earlier was prescribed as a means where TDI would consider the rafter to have the same wind lift and bearing properties as a solid piece of lumber. It also allowed for rafters to be lapped.

    We still have and use the windstorm code for reference and suggestions to engineers. It is not enforceable. However, in 2003 we adopted the IRC and IBC in toto. You're going to love this. It's an exact quote from one of the engineers at TDI made to me in 2004. "We forgot to add the windstorm code, so technically its unenforceable, but we still require it."

    I talked to a TDIWSA engineer in Austin this morning. So now, all houses built from 1998 through 2003 should have the splices as described. Houses built after 2003 follow 2003 IRC as adapted and modified by local code. The wind storm code is now considered never to have been prescriptive.

    He suggested that as HI's, we should note our concerns to our Clients and let them take it from there or we should file formal complaints to TDI for investigation. Yeh, that'll happen.

    Today is a catch up with all the stuff I've put off for months day, so I guess I'll add "what to say now" to the list.

    The only reason some people get lost in thought is because it's unfamiliar territory.
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  12. #12
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    Default Re: Rafter splicing

    The joints in those rafters would perform nothing like modern end jointed lumber. Without plywood gussets on both sides or metal strapping around the joints, they would be too weak to be used as a rafter. The nails are in tension rather than shear, which makes them prone to pulling out.

    I would definitely recommend gussets designed by an engineer. Although a decent carpenter with some glue and nails could easily add plywood to both sides and that would be strong enough.


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    Default Re: Rafter splicing

    Quote Originally Posted by Jerry Peck View Post
    Today, that would be referred to as "end jointed lumber".

    From the IRC.
    - R802.1.2 End-jointed lumber. Approved end-jointed lumber identified by a grade mark conforming to Section R802.1 may be used interchangeably with solid-sawn members of the same species and grade.

    You guys are missing the obvious,

    That *is* "end jointed".

    Nowhere am I saying or implying that it is 'approved' "end jointed lumber.

    Which is why I posted the code section I quoted again above.

    I will highlight parts of it to help you understand what I am saying.

    - R802.1.2 End-jointed lumber. Approved end-jointed lumber identified by a grade mark conforming to Section R802.1 may be used interchangeably with solid-sawn members of the same species and grade.

    Now ... we know *that* "end jointed" rafter in the photo "is not":
    a) "approved"
    b) "identified by grade mark"
    c) and thus cannot "be used interchangeably with" solid sawn lumber.

    *Just because* "it is not" approved or grade marked does not mean 'it is not' "end jointed".

    Those pieces "are" jointed at their ends, and jointed by a large single finger joint (scarf) joint.

    It was most likely done long before "end jointed" lumber became recognized, but that does not alter the fact that 'it is' "end jointed".

    Don't confuse 'approved and grade marked' with 'what is', that is just 'what is' 'approved and grade marked'. A car speeding down the interstate at 90 mph 'is still' "a car speeding down the interstate at 90 mph", regardless as to the posted speed limit being only 70 mph - 'what is' "is". Just like that "end jointed" lumber.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
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    Default Re: Rafter splicing

    Jerry, you forgot to use the emoticons!
    I took you seriously when you said that today that would be called end jointed lumber.

    Jim Luttrall
    www.MrInspector.net
    Dallas, Texas

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    Default Re: Rafter splicing

    Quote Originally Posted by Jim Luttrall View Post
    Jerry, you forgot to use the emoticons!
    I took you seriously when you said that today that would be called end jointed lumber.

    Jim,

    Whhoooossshhh!

    I was/am serious "today that would be called end jointed lumber". Remember, I am not saying "today that would be called approved and grade marked end jointed lumber".

    Okay, what would you call it, if not "end jointed"?

    Are not the two ends jointed together?

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

  16. #16
    Frank Kunselman's Avatar
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    Default Re: Rafter splicing

    I'll provide my two cents worth on the spliced rafters. While you will find no direct refrence to them in the codes, they are addressed by interpretation of the intent of the code.

    R801.2 requires rafters to be 'capable of accomodating all loads imposed'.

    R301.1 requires that framing '...all parts thereof, shall be constructed to safely support all loads...in a system that provides a complete load path...'

    Further, R301.1.3 states 'When a building of otherwise conventional construction contains structural elements exceeding the limits of Section R301 or otherwise, not conforming to this code, these elements shall be designed in accordance with accepted engineering practice.'

    Looking further, back to the Legacy Codes, the SBC covered the problem quite well. 2301.2.1 'The quality and design of wood members and their fastenings used for load supporting purposes shall conform to good engineering practice..'
    2301.2.2 'All members shall be framed, anchored, tied and braced so as to develop the strength and rigidity necessary for the purposes for which they are used.'

    Based upon questioning 'the ability to accomodate loads imposed', 'ability to safely support all loads', 'exceeding the limits and not conforming', 'braced so as to develop the strength', 'accepted or good engineering practice', and 'strength and rigidity necessary' I require spliced rafters to be supported at the splice down to the structural framing or provide engineering.

    I hope this helps.


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