Replacing The Roof Decking Boards

The roof design is the contemporary postwar modern low-sloped roofline, characteristic of a Ralph Haver style. Not too much is left of the original top surface. What is left looks like laminated roof felts with asphalt tar and a final surfacing layer of gravel or slag. 

Later in the life of this roof,  white elastomeric acrylic latex coating was applied over the existing top surface. An attempt to reinforce the roof's ability to withstand the elements and maybe to patch some water leaks.

Like the facia, the roof decking boards (plywood) had been exposed to weather too long and are damaged. Presently the condition appears that not all the boards may need replacing, but this thought may change as boards are removed.