Buying homes with additions built on

[Cameron Foster]

My partner and I have found a potential triplex with good bones and great potential but we have one concern about the addition that was constructed. The previous owners added to the second story but did not demo the old existing roof. Instead they decided to frame the new addition directly to the roof of the original house leaving the roof exposed in the attic of the new addition. I was just wondering if anyone has ever seen this before and if so was it a big issue?