Results 1 to 15 of 15
  1. #1
    Join Date
    Mar 2008
    Location
    Charlotte NC
    Posts
    2,303

    Default No purlin - just braces.

    1989 home, way in the back attic where no one is suppost to go, the 2x6 rafters have 1x4 braces to reduce span. (that's above the garage) The rafters above the kitchen have some semblance of bracing, but doesn't catch all of the rafters and is just plane poor!

    My question is, are the 1X4 braces ok? If they are, should the buyer/seller (negotiable point), put there money in having a competent framing contractor correct the bracing without spending several hundred on an SE? Or get an SE to tell them it needs to be fixed?

    Similar Threads:
    ***IMPORTANT*** You Need To Register To View Images ***IMPORTANT*** You Need To Register To View Images
    Member Benefits1

  2. #2

    Default Re: No purlin - just braces.

    What is the rafter span?

    Clarksville Home Inspection
    JW Goad
    TN License #307 | KY License #2402

  3. #3
    Join Date
    Mar 2008
    Location
    Charlotte NC
    Posts
    2,303

    Default Re: No purlin - just braces.

    Quote Originally Posted by John Goad View Post
    What is the rafter span?
    Between 12 and 13'. (without brace)


  4. #4

    Default Re: No purlin - just braces.

    That should be well within what would require a mid-span support.
    Was uneven deflection visible across the roof line on the exterior?

    Clarksville Home Inspection
    JW Goad
    TN License #307 | KY License #2402

  5. #5
    Join Date
    Mar 2008
    Location
    Charlotte NC
    Posts
    2,303

    Default Re: No purlin - just braces.

    Everything looked straight. We don't have heavy snows here so code is somewhat of an overbuild. (But "code")


  6. #6
    chris mcintyre's Avatar
    chris mcintyre Guest

    Default Re: No purlin - just braces.

    Vern,
    You said this is over a garage, what are they bracing from? Even with stick built roofs we often use trusses over the garage because of the open span with no walls to brace to. If it's not a very deep garage we will use LVL's (parallel with the ridge) and have it sized so we can brace the roof from it.

    From the pictures it looks like they tried to make their own trusses (no purlin and 1x4's for every rafter).


  7. #7
    Join Date
    Sep 2008
    Location
    Texas
    Posts
    745

    Default Re: No purlin - just braces.

    When you say betwenn 12 and 13 feet is that running up the rake with the rafter or horizontal parallel with the ceiling joists. That makes a lot of difference because rafter lengths are measured horizontally and not up the rake.

    Also if you could get a species of lumber that would be very helpful in determining if the sizes are adequate.

    These rafters may be okay or they may need additional bracing...hard to determine without clarification on length and species.


  8. #8
    Join Date
    Mar 2008
    Location
    Charlotte NC
    Posts
    2,303

    Default Re: No purlin - just braces.

    Quote Originally Posted by chris mcintyre View Post
    Vern,
    You said this is over a garage, what are they bracing from? Even with stick built roofs we often use trusses over the garage because of the open span with no walls to brace to. If it's not a very deep garage we will use LVL's (parallel with the ridge) and have it sized so we can brace the roof from it.

    From the pictures it looks like they tried to make their own trusses (no purlin and 1x4's for every rafter).
    Good point. I did not dig to the bottom of the insulation as I was fairly sure at the time, the bracing wasn't right anyway. I have sent the report with recommendation for SE.

    Wayne, FYI the distance is horizontal distance from birds mouth to ridge, and as I said just estimated. I think the lumber is SPF but did not look for the stamp. With the rest of the bracing with obvious problems I didn't feel bad with rec. SE. My original question was regarding the need for the SE or just fix it and be done. The individual 1X4 braces made the fix it and be done a little fuzzy.


  9. #9
    Join Date
    Feb 2010
    Location
    Chesapeake, VA
    Posts
    39

    Default Re: No purlin - just braces.

    Purlins or braces should bear on a bearing wall, girder or an over sized ceiling joist design to carry the load. A 1x4 brace or purlin over 2 feet long is not very good in compression. It will bend.


  10. #10
    Join Date
    Jun 2008
    Location
    Stacy, MN
    Posts
    145

    Default Re: No purlin - just braces.

    The rafters appear to be 16" on center, with a roof live load of 20psf, a 2 x 6, SPF #2 will span 14' - 4" without any additional bracing. At 24" on center it will span 11' - 9". Other species and grades will do even better. You need to find the stamp, look at the table, and figure it out yourself before saying a SE is needed or that it needs to be fixed, because it probably doesn't. 2006 IRC table R802.5.1 (1).


  11. #11
    Join Date
    Apr 2008
    Location
    Massachusetts
    Posts
    191

    Default Re: No purlin - just braces.

    1 x 4's aren't adequate for bracing, as they will be subject to buckling under any significant load. My initial thought is that they were probably installed to provide support for the garage ceiling joists. If that's the case, then the 1 x 4's are actually loading the roof, and not bracing it. More information would be needed on the attic floor framing (size, spacing, span, is there a center beam, etc.)


  12. #12
    Join Date
    Feb 2009
    Location
    Southern Vancouver Island
    Posts
    4,546

    Default Re: No purlin - just braces.

    Quote Originally Posted by Steve Frederickson View Post
    1 x 4's aren't adequate for bracing, as they will be subject to buckling under any significant load. My initial thought is that they were probably installed to provide support for the garage ceiling joists. If that's the case, then the 1 x 4's are actually loading the roof, and not bracing it. More information would be needed on the attic floor framing (size, spacing, span, is there a center beam, etc.)
    Still kicking this one around?

    The builders built trusses. They laid the rafters out on the ceiling joists and joined them with 1X4 so they could stand them up as trusses, but they may be fine as rafters without the webs. (Not enough info to be sure).

    How about "SE or qualified builder"?

    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

  13. #13
    Join Date
    Apr 2007
    Location
    state of jefferson
    Posts
    520

    Default Re: No purlin - just braces.

    Quote Originally Posted by Fred Weck View Post
    The rafters appear to be 16" on center, with a roof live load of 20psf, a 2 x 6, SPF #2 will span 14' - 4" without any additional bracing. At 24" on center it will span 11' - 9". Other species and grades will do even better. You need to find the stamp, look at the table, and figure it out yourself before saying a SE is needed or that it needs to be fixed, because it probably doesn't. 2006 IRC table R802.5.1 (1).
    i agree!


  14. #14
    Join Date
    Mar 2007
    Location
    Healdsburg, CA
    Posts
    1,741

    Default Re: No purlin - just braces.

    As a very old roof framer we never depended upon nails for supporting rafter as we always notched our purlin supports.
    If in fact those are 1x4 rafter supports, they are both useless and don't meet code. Also, what are the bottoms of those braces bearing on? This installation has a seriously bad odor.

    Jerry McCarthy
    Building Code/ Construction Consultant

  15. #15
    Join Date
    Mar 2008
    Location
    Charlotte NC
    Posts
    2,303

    Default Re: No purlin - just braces.

    The fact that there is not a clear consensus on this makes me feel better with the decision made to refer to SE. (He needed to be there for other reasons anyway)


Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •