How can the I-Joist work as a rafter tie

[sharbin]

In the plan 20x30 1.5, it is mentioned that either 2x12 or I-joist can be used as a rafter tie.
I know for load bearing purposes the I-joist do the job, but as a tie? How do you install and attach it to the walls to make sure that it can handle the tension? any special hardware?

Thanks,

[glenn kangiser]

Sharbin, I have seen directions to build up the ends with glued on wood in some applications and I would bet that is what they want for this.  I'm pretty sure maybe an 8" long block - probably ideally thick plywood or doubled glued layers at the ends would do it.  Seems there were detailed instructions from the I joist company - maybe available online.

[sharbin]

I looked at couple of web sites, but non (that I can understand ) mention anything about horizontal tension.

[John Raabe]

Sharbin:

Please give me a reference to where I call out an I-joist as a rafter tie. It can be done with web blocking but the floor joists are not rafter ties in the 1.5 story plan. Outward thrust from roof loads is dealt with in the truss, collar ties and the exterior walls.

Page 9-20a of the booklet shows a true rafter tie when doing the full cathedral roof section. That double 2x8 configuration is working in tension to resist the outward forces from the rafters.

[sharbin]

Thanks for the clarification. What I was referring to is where you call for an I-joist in the loft area instead of the 2x12. I know that this is a rafter joist, but I called it a rafter tie as I thought that it also acts as one and I wanted to know how it does its job as a tie ). I totally forgot about the role of the collar ties and was concentrating my attention on the joist.