Attic Cross Member Question

Discussion in 'Framing and Foundation' started by Rmwoiak, Feb 18, 2013.

  1. Feb 18, 2013 #1

    Rmwoiak

    Rmwoiak

    Rmwoiak

    Member

    Joined:
    Jan 3, 2012
    Messages:
    10
    Likes Received:
    0
    Guys,

    I am getting ready to put some flooring down in my attic to make more room for storage. I have three cross members (?) in my attic that I was unsure about. I have included a few pictures below. They are located in my town house which was a gable roof. The cross members are about 8in tall but only a 1/2 in thick. They don't seem very sturdy so I cant imagine they are structural. I wanted to see if anyone could identify them and see if I am able to safely remove them. Thanks guys.

    2013-01-05_15-13-35_520.jpg

    2013-02-18_17-12-46_198.jpg

    2013-02-18_17-12-54_628.jpg
     
  2. Feb 18, 2013 #2

    nealtw

    nealtw

    nealtw

    Contractor retired

    Joined:
    Nov 4, 2010
    Messages:
    23,892
    Likes Received:
    3,117
    They are ties to stop the roof from sagging. They are very much structural and should not be removed.
     
  3. Feb 18, 2013 #3

    Rmwoiak

    Rmwoiak

    Rmwoiak

    Member

    Joined:
    Jan 3, 2012
    Messages:
    10
    Likes Received:
    0
    Thanks, I just wanted to double check before I did anything dumb.
     
  4. Feb 19, 2013 #4

    Wuzzat?

    Wuzzat?

    Wuzzat?

    Well-Known Member Sponsor

    Joined:
    Jan 20, 2010
    Messages:
    2,471
    Likes Received:
    175
    How are they fastened at the ends? For structural purposes I'd think they'd use through bolts and thicker wood and a lot more of them.

    Since the force spreading the roof is uniform, the horizontal roof line should look wavy when sighted at right angles to these boards if these are resisting a tensile force. The roof width would then be narrower at the few places where these strips are anchored.
     
    Last edited: Feb 19, 2013
  5. Feb 19, 2013 #5

    JoeD

    JoeD

    JoeD

    Well-Known Member

    Joined:
    Mar 16, 2006
    Messages:
    1,527
    Likes Received:
    273
  6. Feb 19, 2013 #6

    Wuzzat?

    Wuzzat?

    Wuzzat?

    Well-Known Member Sponsor

    Joined:
    Jan 20, 2010
    Messages:
    2,471
    Likes Received:
    175
    Ignore JoeD.

    The ones on my porch are 2 bys, three sandwiched with a center one for appearance. At least 12 nails at each end.
     
    Last edited by a moderator: Feb 19, 2013
  7. Feb 19, 2013 #7

    poppa

    poppa

    poppa

    Member

    Joined:
    Feb 3, 2013
    Messages:
    17
    Likes Received:
    1
    I'm an old carpenter and we called those wind braces and put one on every other set of rafters. You really should put more in you don't have enough.
     
  8. Feb 23, 2013 #8

    CallMeVilla

    CallMeVilla

    CallMeVilla

    Well-Known Member

    Joined:
    Feb 9, 2010
    Messages:
    1,651
    Likes Received:
    594
    When I built a large shed last year, I used 2x4 lumber for the ties to the rafters. Solid roof. Never going to sag and the wind will not lift it.

    KEEP those ties in place.

    PS If you are putting down plywood for storage, DO NOT lay the wood over any wires which are sitting on top of the ceiling joists. This could be hazardous! :p
     
  9. Feb 24, 2013 #9

    AndyGump

    AndyGump

    AndyGump

    Drawer of Homes

    Joined:
    Mar 27, 2011
    Messages:
    52
    Likes Received:
    5
    If you want to do away with them you would have to get a permit to make a relatively small change like this and install 20 gauge x 1-1/4" straps across the ridge from rafter to rafter.

    Andy.
     
  10. Feb 25, 2013 #10

    nealtw

    nealtw

    nealtw

    Contractor retired

    Joined:
    Nov 4, 2010
    Messages:
    23,892
    Likes Received:
    3,117
    Andy: I would like to be polite but, wrong. Collar ties are placed in steep roofs at the half way from the birds mouth to the peak to supply support against sag. By adding this support, they make the span of the rafter 1/2 of the full length. Your straps would be added to prevent failure in high winds and is a different problem.
     
  11. Feb 25, 2013 #11

    AndyGump

    AndyGump

    AndyGump

    Drawer of Homes

    Joined:
    Mar 27, 2011
    Messages:
    52
    Likes Received:
    5
    HI Neal, you are polite, on this topic I guess we will just have to agree to disagree I guess.

    It sounds like you are describing a purlin rather than a collar tie but of course those run perpendicular to the rafters.


    Andy.
     
  12. Feb 25, 2013 #12

    nealtw

    nealtw

    nealtw

    Contractor retired

    Joined:
    Nov 4, 2010
    Messages:
    23,892
    Likes Received:
    3,117
  13. Feb 26, 2013 #13

    AndyGump

    AndyGump

    AndyGump

    Drawer of Homes

    Joined:
    Mar 27, 2011
    Messages:
    52
    Likes Received:
    5
    I have to say, who ever the self-described "Expert" is in the link you provided has a lot of things really mixed up.

    A collar tie runs from a rafter on one side of the ridge board to the opposing rafter on the other side. Are usually connected with 16d nails, are required to be minimum 2x4 lumber now but for a long time 1 x material was O.K. to use. They are usually about 1/3 the way down from the ridge board too.
    Now rafter ties are used to keep the walls from spreading and ties the bottoms of the rafters, normally your ceiling joists perform this function in most homes but some homes have ceiling joists that are perpendicular to the roof rafters, hence the use of rafter ties in these situations.

    Purlins run perpendicular to the rafters, usually at about the mid point of the rafters, are a minimum of the depth of the rafters and are supported by 2x4 or greater bracing on 48" centers to a bearing wall that will carry the load of part of the roof to the foundation.

    Andy.
     
  14. Feb 26, 2013 #14

    nealtw

    nealtw

    nealtw

    Contractor retired

    Joined:
    Nov 4, 2010
    Messages:
    23,892
    Likes Received:
    3,117
    A collar tie runs from a rafter on one side of the ridge board to the opposing rafter on the other side. Are usually connected with 16d nails, are required to be minimum 2x4 lumber now but for a long time 1 x material was O.K. to use. They are usually about 1/3 the way down from the ridge board too.
    Your first post indicated this can be removed. If you are suggesting to build a knee wall to barring, an angle wall to barring or a purlin supported to barring wall yes, but just remove it, not a chance. Not without checking loads live and dead and the span of the rafter.
    BTW For walls that do not have rafters landing on them. A 1x4 or 2x4 nailed across the ceiling joists from wall to wall hold the wall straight. Commonly called cat walk placed no more than 10 ft apart are found in rafter houses and houses with trusses and homeowners should be aware of their importance when applying a deck to the ceiling joists.
     
  15. Mar 5, 2013 #15

    BridgeMan

    BridgeMan

    BridgeMan

    Well-Known Member

    Joined:
    Aug 11, 2011
    Messages:
    744
    Likes Received:
    80
    If a collar tie is to perform as a structural member, it must be rigidly attached to rafters at each end with through-bolts to be most effective. A flimsy 1x of any depth will not do well, as it is prone to bowing and buckling when acting in compression to resist vertical rafter forces.
     
  16. Mar 5, 2013 #16

    nealtw

    nealtw

    nealtw

    Contractor retired

    Joined:
    Nov 4, 2010
    Messages:
    23,892
    Likes Received:
    3,117
    If the only concern is lift do to wind the tie will only prevent tension and a 1/4 is acceptable, nailed. More than 1/3 from the top.
    If the rafter is overspanned, a 2x4 or 2x6 will be called for somewhere between 1/3 and 1/2 from the top to serve as tension and compression, bolts are seldom called for.

    The plans for new construction usually read something like trusses supplied by others or (built on site) The city will ask for an engineered design on the roof, nothing more to think about.
    The bottom line is if it looks like structure, it likely is and don't remove it until you know what the h!!! you are doing.
     

Share This Page