Hi EPops,

I second everything Tim suggested, and probably would take the joists up to 6x8 or place closer. In most frames I've experienced like this they are seldom further apart than 24".

I would add, that PE and Timberwrights alike don't just design a structure (as long lived as timber frames often are) for only one intended purpose. You personally may not need a combined load capacity as high as some would suggest...Nevertheless, what is reflected in Tim's humorous (but very accurate) "tractor" or "engine" storage comment at the end of his post has much weight and wisdom...This frame could have all manner of intent placed on it (as such structures often do in the course of time) and its our job to think of this in our design and building of them.

Just some food for thought...