How to negotiate on a rehab property

[Niyi Odumosu]

I recently had a home inspected after having my offer on it get accepted. The home is in an up and coming area in West Philly walking distance from a shopping center and near a new train station station that is currently being constructed. Although my original offer price was accepted, I realized during the inspection that there are some mold issues on the ceiling and potentially behind the wall. There are some other cosmetic issues as well but the mold is what I'm most concerned about. Given that there is a possibility that I may have to tear the walls down, does anyone think it's worth it to continue to invest in this rehab property? If so, how do I go about negotiating a lower purchase price or seller's assist to get some additional funds to fix the mold. Any insight on from some experienced rehabbers would be much appreciated!!! Thanks!