Help spread the word / share us on your favorite social media networks

Facebook Twitter StumbleUpon Reddit LinkedIn

Results 1 to 3 of 3

Thread: rafter ties

  1. #1
    Join Date
    Mar 2014
    Posts
    12

    Default rafter ties

    Im planning on installing rafter ties in my 1952 cinder block home. It has no rafter ties at all. Every time Im in the attic and look around, I wonder what holds up my roof. The ceiling joists run parallel to the roof ridge. Im also going to install collar ties. Currently there are only two. The roof does not have much sag and the walls have no apparent bow. However, Im adding hurricane straps, supports for the gable ends, and extra fasteners to hold the roof planking to the rafters. Vertical rafter supports and then a new roof cover too. So, I decided to add the rafter and collar ties too.

    In my research, I have discovered the idea of using cable instead of wood for the rafter ties. Cable is stronger and will allow me to remove some of the pressure on the side walls, using a turn buckle I can pull up the roof slightly. I have a string pulled straight across the ridge inside the attic. I do not plan on trying to take out all the sag (3'), just a little to remove some existing pressure on the side walls. Cable will be easier to install too.

    I have two unresolved questions concerning using cable. One is what size. I have found several formulas on the net on figuring side thrust, but each i use gives different results. Its most likely because I am using the formulas incorrectly. I have spent many hours trying to figure this out. Now i just want answers. Can someone help?

    Also, many sites discuss the number of nails/screws/bolts that are needed to fasten wood rafter ties. Using enough fasteners to hold it secure. Now, Im not sure how many that i need to connect the cable to the rafters. One would be easy, more requires a special designed fastener.

    Another reason for not using wood rafter ties is that I would need to cut each rafter into three pieces to get them thur the attic access hole. I have a bad back and cable is so much lighter too.

    This site formula gave me thrust of 1250 http://www.timbertoolbox.com/Calcs/RafterThrust.htm

    this one gave me 18000 http://www.timbertoolbox.com/Calcs/raisedtiethrust.htm

    I have used other sites too. I just don't understand all this math.

    So, I want to know how strong a cable to buy and if a single attachment point to the rafters is adequate.

    14 rafters (not including the gable rafters), 24" oc 2x6
    4/12 pitch
    room measurement eve to eve 205"
    shingle roof

    tks much,
    pa

  2. #2
    Join Date
    Feb 2012
    Location
    Lala land, OH
    Posts
    235

    Default

    See....

    here

    here

    here

    here

    here

    here

    here

    here

    and...

    here

    If you have a valid question, please respond to one of your 37 posts across multiple boards about it instead of starting a new post or posting the same thing over and over. New posts will be treated as SPAM and dealt with according to our SPAM policy. Thank you.

  3. #3
    Join Date
    Mar 2014
    Posts
    12

    Default

    Quote Originally Posted by Mr T View Post
    See....

    here

    here

    here

    here

    here

    here

    here

    here

    and...

    here

    If you have a valid question, please respond to one of your 37 posts across multiple boards about it instead of starting a new post or posting the same thing over and over. New posts will be treated as SPAM and dealt with according to our SPAM policy. Thank you.
    make note. dont use ez forum. Other forums work and I get good advice and clarifying my question weeks or months later does help. I have gotten several good tips just from this last post a few days ago, however ez dont like that. so bye bye

    p

Similar Threads

  1. looking for rafter straps
    By paulmars in forum Building Construction
    Replies: 1
    Last Post: 01-20-2015, 07:43 AM
  2. rafter cable ties
    By paulmars in forum Building Construction
    Replies: 0
    Last Post: 05-30-2014, 08:10 PM
  3. sagging rafter, installing sister
    By paulmars in forum Building Construction
    Replies: 5
    Last Post: 04-04-2014, 06:32 PM

Posting Permissions

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