- Q. Does a cathedral
shed roof addition need collar ties to restrain the outward
thrust of the rafters?
A. A shed roof with a
proper shear connection at the ridge has no lateral
thrust. Think of a ladder leaning
against a building. Imagine the ladder has wheels at the
bottom. With no restraint at the top, the ladder will roll away
from the building. Attach the ladder to the building at the
top, however, and it stays put. A shed roof is similar; as long
as it’s properly attached at the top, the bottom
can’t move. "Collar ties" are an exercise in futility.
Use them as ceiling joists if needed; otherwise, leave them