Is the delaminating plywood FRT? There was a new roof installed and only about 25% of the original sheathind was removed. It appeared that they installed the plywood over the 75% of the other sheathing that may be FRT.
I know the origianl sheathing is a bitch to remove as it breaks into little pieces.
the color of that sheathing combined with its delamnation does sound like FRT, as other have said it should be marked, but when it degrades the label cannot be seen.
Was this on a condo or townhouse with common party walls? also when was it built?
The home was built in 1946. It is a single family ranch home. My accross the street neighbor has the same sheathing as I remember last year when it took him days to tear off a small area of the sheathing as it breaks into little pieces and doesnt remove like plywood or flakeboard.
I very much doubt that that is in fact FRT, FRT would normally only be used on property such as condos and town houses where fire protection is required for the roof decking 4 feet either side of a party wall, also FRT was not used before the late 1970’s.
I believe that what you were looking at was just older moisture damaged plywood which had darkened due to age, damp, and airborne contaminents.
I’m with Gerry. I used to see FRT all of the time, and have never seen it on a single family home. It is more expensive, and even if the 40’s roof was re sheathed in the 70’s it is very doubtful the roofing contractor would have spent more money for a sheathing that was not required.