The horse barn at Christian's old farm was in desperate need of a new roof which we are busy installing this month. We will preserve the sunlit atrium with polycarbonate sheets that interlock with ribbed sheet metal below it; discarding the plywood and using the purlins to attach to. An experienced friend told us that using plywood under a metal roof shortens it's life by trapping water and rotting. This saved $1500 for 75 sheets of plywood besides the hard labor of installing it (in 100 degrees of heat). "Marvic Supply" gave us contractor's pricing on an "Ideal" painted metal roof system.
We are set up with three large tarps (to collect the removed old asphalt shingles), the old steel door on saw horses, several ladders, a new (craigslist) Shop-Vac, and a long-term 20 ton dumpster graciously delivered by the previous owner. The gutters were cleared and vacuumed and the plywood popped off from below with long 2" X 4" boards.
Nearby, an old combine overlooks our work with a "wash stand" in the shade.