Answer: I asked several real estate agents who confirmed that in Pennsylvania, rehabs do not require such disclosures. That said, not every rehab is done correctly, so perhaps full disclosure, while not required, would be wise.
Another part of your question concerns changes in plans for the rehab. When applying for permits on a rehab, you're required to submit plans for approval of the permits. Once you have permits in hand, if the rehab doesn't go according to the plans submitted, is there an expectation that new plans should be submitted showing the new work?
You said you were able to secure the plans the previous owner submitted to the city to perform the rehab. What the plans show, you said, doesn't match what was built or rehabbed - a roof deck was moved to a rear deck, a slanted roof became a flat roof, and a bathroom was turned into a regular room.
In most municipalities, each time a portion of a rehab project is completed, an inspector from the building department must come out and sign off on the work. I would assume that some problem arose with each of those pieces of the rehab, and the changes were made to comply with what the inspector considered a problem.
That said, normal procedures would require that new plans for the changes be submitted, or that those changes be noted on the original plans and the building department be notified of them.
Since a certificate of occupancy had to be issued before the house sale could go to settlement, I assume that the building department issuing the document signed off on the changes.
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