Hello, My son and I built this barn out of necessity. We knew nothing about such a construction and made many mistakes. However, here after nearly nine years, it is still standing firm ... except for the ends of the roof. This is where I need some information. We made the roof out of OSB board, placing tar paper over it; then coating it with tar; then placing rolled roofing on top (starting from bottom about half inches past ends of rafters and overlaping it 2 inches as going up to the top of the roof). Now we have noticed the low ends of the OSB boards (exposed to weather) on each side of the roof are rotting away and in need of repair. (The rafters are 2 x 6 and look good all around.) I have given this some thought and would like some feed back as to whether or not my ideas might work well. 1. I thought of placing some flashing over the ends of the roof all the way around (on top of the present roofing and folded over the end of the rafters), placing either roofing tar or all-weather-silicone cauking under it and tacking the flashing to the rafters (both on top and over the ends). 2. I thought of taking treated 1 x 4 boards and tacking them at the ends of the roof on top of the present rolled roofing; placing either roofing tar or all-weather-silicone cauking under it. (This, alone, would not protect the ends of the existing OSB boards from further decay.) I would appreciate suggestions as to how to repair this roof in as easy a way as possible as we will be doing it ourselves and neither are very well at the time. Also, I need to keep cost down.