Hello trulia fan- I have some experience with mold and minor remediation, though I am not an expert or certified in that respect. I have built and managed numerous homes, so maybe take this as a general guideline; this is a personal, not a company, opinion-
In a practical sense, with all other available homes out there, I would maybe just pass and go on to the next house that has been on the market for over 6 months.
You need to get a quote from a qualified local contractor on removing all the building components that would need to be replaced, and installing and finishing/ painting of such before you make any offer on the house. That should be in the negotiations with the seller, and the seller's agent probably anticipates that.
Mold is much of time overly "hyped"- most of the horror stories you hear in the media are from a form of black or toxic mold. Regular mold is not nearly as dangerous. Keep in mind that to some extent there is mold in every house and in every building- somewhere. It's just a matter of if it is a hazard. And a professional, not me, would have to tell you that and test it.
If the roof has been fixed and there is no recent leakage, and the attic is well ventilated, most likely the mold will not return to be a further problem. Once the moisture or water problem is cured, the mold cannot spread and becomes dormant.
My final disclaimer- I'm not a mold expert- just trying to give some overall and basic info :)
Thanks and good luck,
Ken L.

Dear home buyer,

WOW-You sound like you are feeling guilty. No low price property is worth the health of your family. So if the mold is in the building you should remove all of it. It is a living organism and one that will return encapsulated or not, in my opinion.

I have previewed, sold and become very ill from dealing with moldy buildings caused by ignorant, lazy and cheap builders and home owners. My husband and I have walked away from what some would consider steals, because of mold. It’s just not a friendly opponent there is no negotiating with this organism.

Good Luck,

Karissa Moore, Realtors
Hogan Real Estate,
978/410-5248

I agree with the below ... Mold can be a very serious problem and could have a serious effect on value and future value.

Joshua is right, it's important to get a professional opinion from a reputable company that can remedy this problem for you. I would like to add that my husband rehabs houses & all the advice he has received on the subject has been to make sure that you remove all the mold. Encapsulating it would not stop it from affecting the health of the people who live in the home. In my opnion, that's too much of a risk to take.

I don't know that this is a question anybody here should really answer for you...mold is a very touchy subject and one with many legal ramifications because you're asking about HOW to remediate the issue...

I would contact a company like servpro (not an endorsement, just an off-the-top-of-my-head recollection) and have them tell you what's involved in remediating and then warrantying the problem.

Some buyers will care more about it than others.