I am building a shed and I need to build it in two halves so I can take it off the foundation if I need to. The problem is that due to the dimensions, I have to split it in such a way the split line goes across the roof perpendicular to the ridge. The fact that I will be using wooden shakes makes this even harder. What can I do to keep it from leaking?
If the two halves of the shed are built to be structurally sound while separate, then there is no reason that each roof can't be built slightly asymmetrically so that one overlaps a portion of the other to provide weatherproof protection, like this:
Some tweaking of the interface would be needed to make it practical and convenient, but the basic idea would be to build it so there is at least 6 inches of overlap where the higher one covers the lower one.
If you are not attached to cedar shingles then I would say use a metal roof. If your metal overlaps both pieces enough then you can get a pretty water tight seem just due to the overlap of the metal. Though taking it apart too much will bend the metal. I suppose if you attached all your shingles to plywood that hangs over in a similar fashion you might get the same result.