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Tying Rafters to I Joists

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  • Tying Rafters to I Joists

    I have a chance to build a 30'x50' garage. I am a new, small builder/remodeler with some framing experience (I have built several additions, small garages, and decks). I usually work by myself. The requirements for this garage are that there be NO interior walls and that the outside walls be 14' high. I'm planning on using 2x6 12' LSLs on an 18" concrete stem wall, which, with the sill and bottom and double top plates, should give me the required 14'. I'm planning on using 30' 16"x5 1/2 Trus-Joist I-joists with a 16" rim joist. I have at least two problems which, if I can't solve them, will mean I won't get the job.
    ONE, how can I get the I-joists up on the top plates?? I can round up some help (manually) but I'm afraid of the swaying that may occur when lifting the I-joists. Any suggestions would be greatly appreciated!!! (I would rather NOT use a crane (expense!))
    TWO, how do I tie the rafters to the I-joists or do I even tie them to the I-joists?? Normally, I would just nail the rafters to the ceiling joists at the top plate and cut off the roof protruding joist ends in the plane with the roof; however, Trus-Joist says that the I-joist CANNOT be slope-cut farther back than the distance of the top plate. One idea I had was to a 2x6 top plate and then put the rafters to the top plate as I normally would. I would then install rafter ties using 2x6 sawn lumber, lapped in the middle and tied to the rafters and slope cut at the ends. The lapped rafter ties would rest on the I-joists (on edge) and a plywood subloor could be nailed to them. Is this overkill?? Is it structurally valid???

  • #2
    Re: Tying Rafters to I Joists


    For me the crane is the best way, as far as time and money, and you wont "Kill Your Back"

    If your not going to figure for a crane, you definitely need help.

    Even if you were to use a crane you would need at least one other guy, one on one side, one on the other, to grab each side of the beam.

    If you don't use a crane, lets say you just have one other guy, I'm assuming your a pretty strong guy ;-).

    I would nail the one side of your 16" rim board first, than on the opposite side I would set the ladder up on the corner of the building.

    Precut all your beams first, then you grab one end your helper grabs the other end, you walk your end up the ladder and rest it on top of your sills.

    You have to stand on top of the sills and pull while your helper pushes, at first you have to pull verticle, then you will feel the beam starting to come down toward your (head) to balance itself. "Sounds easy ha"

    This all depends on how comfortable you are up there. Slide the beam across the side of the foundation until you but into your rim joist.

    Do the same procedure with the second one, but what you want to do is try and slide that one on top of your first one, it will bow the first one down, if it's to much have someone in the middle with a ladder to take the weight off and help you push and slide the beam. You don't have to worry about the first beam sliding because your rim board is there to hold it in place.

    Just keep repeating until you get to the end, then nail them up.

    Second concern, what do your plans say about the rafters?

    I just did a garage 26'x38' we put plywood on top of the I-Joists, I had a 3' kneewall first and then my rafters.

    In your case, like you said 2x6 top plate would be the best way.

    Is there going to be storage above?
    Were you plannig on plywooding the second floor? if so put plywood down first than your 2x6 plate than nail your rafters on top of your plate.

    Hope I helped you a little bit.
    Let me know.


    • #3
      Re: Tying Rafters to I Joists

      Thanks for the input Joe, but I think you may have misunderstood my concerns or (most likely!) I just didn't do a very good job of laying out my situation.

      In your response, you say that I should "Slide the beam across the side of the foundation until you but into your rim joist." and earlier you mentioned "sills". These I-Joists are going up as ceiling joists on top of a doubled top plate 14' in the air. There is NO foundation involved here. Again what I'm most worried about is the swaying/bowing of the I-Joists over the 30' as I (and at least one helper!) lift them onto the top plates. If someone has experience in this area I would appreciate a little input.

      As for my second concern, tying the 2x8 rafters to the I-Joists, I usually place the rafters so that they come down alongside the ceiling joists and then besides nailing rafters to top plates, I can also nail into the joists. This, in effect, creates a "truss" once you throw in the collar ties and purlins. In my opinion, it prevents the roof and attached walls from blowing out due to snow load...yes I'm in the Northeast. Anyway, I've seen buildings where just that same thin has happened and it's almost always because they didn't use rafter ties to hold the whole thing together. So, what I'm asking for is a way to tie the rafters together across the width of the building; all I could come up with is to lay, on edge, lapped 2x6s on top of the 16" I-joists which would cover the 30' from side to side and which I could side nail to the rafters. I also noticed that Simpson has a tie which will take a slope (is adjustable) and can be installed under the rafter and tied to an I-Joist. Would this give me enough structural integrity to eliminate concerns about rafter ties??

      Any and all comments, suggestions, and assistance would be greatly appreciated.

      Thanks much
      Joe Principato


      • #4
        Re: Tying Rafters to I Joists


        I did misunderstand you about not having concrete walls.

        I've been Framing for 19 years I've tried a million different ways to do things.

        But what I can see is that your foundation is 18" high and your using 2x6 lvls 12' high for your walls plus your bottom sills & your two top plates.

        If thats the case once you frame all those walls brace and sheath them, now you have four walls.

        Now you can go by what I told you in my first post. Instead of concrete walls you have wood walls.

        As far as the Swaying/Bowing you said you'll have at least one helper, do like I said you walk up the ladder while your helper pushes.

        You should really get a third guy to support the center so it doesn't sway or bow.

        You can make a T brace or a U brace for the guy
        in the middle so he can lift and support the swaying for you while your walking up the ladder.

        Second way:

        Lean one end of the beam into the bottom of the foundation, and start at the far end and walk the beam straight up the 14' wall with a man on the top plate waiting maybe even tie a rope around the end. I've done this with 36' microlam hips.

        Third way:

        Tie a rope around the end have a guy on the top plate pull the rope while you push up until it sits on your top plate. If your worried about the beam sliding nail some 2x4s perpendicular on the side walls in case you loose the beam it wont go very far.


        • #5
          Re: Tying Rafters to I Joists


          I forgot to mention the last job we did the I-Joist were 46' long we slid the first one up nailed one end to the top plate and kept the other end on the ground.

          Then we braced the middle of the I- Joist and used it as a ramp to slide the rest of them up.


          • #6
            Re: Tying Rafters to I Joists

            Without digressing into your structural intent is there a reason why you are not using storage designed trusses? I assume you want a storage/useable area upstairs? I know you need a crane for this, but 3 people can erect and lock in a 50' garage in a day. I have seen crews of 4-5 do it with a 1/2 day crane rental. You may want to consider additional help from a temp service for the construction trades, not the day laborer rental agencies. If there is no storage required, the trusses are even cheaper and you could suggest an upgrade to storage trusses which could cover your crane cost!

            Depending on the pitch you can wind up with a very large useable space subject to design specs.

            Just a thought!



            • #7
              Re: Tying Rafters to I Joists

              Joe- If it was me, I would ask the TJI supplier about the rafter connection. I have found them to be very helpful in these situations, plus your shifting liability.The whole job sounds like more work than a carpenter and an inexperienced helper should attempt, without the proper equipment.Workmens compensation is expensive enough, without having to use it. Stick with what you know best-you'll end up making more money and less headaches. Greg in connecticut


              • #8
                Re: Tying Rafters to I Joists

                Joe Principato,

                How are you going to stand a 12' tall wall on top of an 18" stem wall with a concrete floor? Assuming that you do have a concrete floor, the bottom of the wall either needs to be framed up off the slab at the heighth of the stem wall or raised with brute strength and ignorance after it is framed. Even with using wall jacks you still need to anchor the bottom of your jack-posts down to a concrete slab which raises its' own set of problems. Your best and safest shot is to rent a reach-type forklift such as a Gehl or Gradall and use that to set the walls and then hoist your I- joists into position. Any work such as this that I can do with hydraulics is a whole lot safer and uses less manpower. A $120-$150 a day for forklift rental pencils out pretty easily.
                I recently built a 40' x 50' garage with 14' walls probably much the same as your project. At various points around the perimeter we had stem walls as tall as 4'. Try standing a 2x6 wall 10' tall up on top of that. I did a raising sequence plan that allowed us to frame almost all of the walls down on the deck, stacked on top of each other. The last wall framed then became the first wall lifted and set on top of the stem walls. We braced everything off from the outside so we had adequate room to maneuver the forklift around. Try to get a lift that has three-way steering so you can "crab" into corners. We built the whole thing with just myself and 2 helpers and a forklift.

                Good luck.


                • #9
                  Re: Tying Rafters to I Joists

                  1) I don't know what your design needs are so i will not comment on your design.

                  2) You are putting up 30' I-joists 14' foot in the air. Unless you put up a lot of staging or have scaffolding that is a high lift.A crane is a lot faster and safer. I would put the band joists up first.

                  3) The I-Joist manufacturers have the nailing schedules and blocking requirements on line. Follow them.


                  • #10
                    Re: Tying Rafters to I Joists

                    Thanks to everyone for their was ALL useful. I will be doing the job except now we'll use attic trusses.

                    Thanks again
                    See ya on the forums
                    Joe Principato


                    • #11
                      Re: Tying Rafters to I Joists

                      now that you've solved the problem, there's no need to see if a genie lift would help, aka a duct jack, I'm sure that would get the tji's up there.