It had been twenty or more years since the house had been roofed. Numerous problems were present, including rooting wood and broken tongue and groove slats. Rather than risk another rainy season, the decision was made to reroof. This would include removal of the old shingles and the installation of a cover of half inch Oriented Strand Board (OSB).
Since the roof is not intact underneath the shingles, great care must be taken to prevent leaking during the inevitable rainstorms. This was done by removing the shingles in four foot rows and layering the OSB before preceeding. Plastic sheets provide the bulk of the protection, but the installation of the OSB limited leaks to joints, instead of widespread.
Each 4 x 8 OSB sheet had to be pulled up using rope and then directed into place. An thermostatically controlled attic fan was installed, allowing removal of the unsightly "whirly birds" seen in the preceeding photograph.
The above picture shows the eventual look for the whole roof, as the left side has already been done.