You never know what you’re going to find when you take off an existing roof. In this instance the asphalt shingles had been installed over a wood shake roof. It became apparent as to why when we removed the cedar shingles. This heritage home had 1″ x 10″ slats for a roof deck substrate that were spaced up to 4″ apart.  The solution was to inlay 1″ x 4″ pieces into the gaps to create a continuous surface.  Just another example of some of the unknowns that must be addressed when you renovate.