Ridge Board Support Dilemma
I have a "gable rafter roof" with a 4x4 holding up the ridge board at each end. The roof's ridge line is about 2 ft from the main load bearing wall that runs parallel to the ridge board. I went into the attic and found that the ridge board had been spliced. Approximately a 2x8 x 12' joined with a 2x8 x 9'. I don't know why they didn't use a continuous ridge board but that's another thread.
Here's the dilemma: I started to remove a partition wall that runs parallel to the ceiling joists but found that it might be holding up the roof in some way. At the ridge board splice there's a 4x4 that is nailed to the partition wall. I will be building a new partition wall approximately 2 ft. from the existing wall. Could I put a new 4x4 there to support the ridge even though it won't be at the splice? Or could I put a coulple of 4x4s in a an upside T formation and lay them across the joists in the attic for the support at the splice?
I've attached a few pictures. The pictures taken in the attic the load bearing wall in to the left. The pictures taken looking at the ceiling from below the load bearing wall is to the right. I've marked the location of the 4x4 with a black arrow.
http://www.diychatroom.com/attachmen...1&d=1231260546 http://www.diychatroom.com/attachmen...1&d=1231262246 http://www.diychatroom.com/attachmen...1&d=1231262351 http://www.diychatroom.com/attachmen...1&d=1231262457 http://www.diychatroom.com/attachmen...1&d=1231262556
I don't know the exact engineering to provide the proper support but I would consider adding collar ties (horizontal boards) at least 1x6's, not more than 1/3 the way up from the joists below, to the ridge. Put one on the pair of rafters closest to the splice and put on two others, two rafters away in each direction.
More collar ties closer to the ridge (2/3 the way up from the joists below) will do the job of fewer closer to the joists. I don't know whether the standard of one collar tie every three rafters is sufficient for a spliced ridge board.
You can do it with the inverted T of 4x4's but keep in mind it is your new partition wall that is supposed to support it, not the rafters.
Thanks AllanJ. I've come up with a primitve illustration to see if I understand you correctly. The red line being the collar tie you've suggested.
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