I had some dry rot and moisture issues in my attic because ventilation was not installed correctly 20 yrs ago when the roof was done. I am a new owner (10 months) and decided to replace my roof.
Yesterday the roofer called and said the entire North side of my cape cod needed new OSB. I said ok and when I showed up 2 hours later the new OSB had been put down and they were starting to shingle. The roof was finished yesterday, when I got home from work I went into my attic and I noticed the OLD OSB was still there. They did not replace the OSB, they just went over it.
My concern is the old osb dry rot affecting the new osb. Also, is there now a weight concern with the two layers of 1/2" OSB and shingles?