I am putting in a shed dormer. Current rafters are 2x6, span is 14 feet. Going from a 12/12 to a 6/12 pitch. I have no ridge now, the rafters are angle cut and meet each other at the peak. I am thinking about ordering I joists instead of dimensional lumber. What I am not sure of is if I can use an I joist without supporting it at the peak. If I install a ridge board where the dormer is going, can I use joist hangers to hang the I joists?