Generally, houses with known issue should be avoided

including foundation issue, bad lot location, and mold.

The risk with the mold issue is that before you open it up, it is hard to gauge the extent of damage. However, you won't be able to open it up until you close - which could be too late to find out the truth.

Thus whether it worths the 20% discount or not, it is hard to say.

Thanks for weighing in.