Tia,Based on the information provided I don't see how this work can be completed for your $30K estimate.If the second floor is burned out... you may be faced with replacing all of the rafters and roof, certainly all of the wiring throughout the house, most of the plumbing depending where the bath is on the second floor... plus all of the drywall from the smoke/water damage in the rest of the house.I have some experience in fire damaged properties... and I can tell you that when I did my first one which I didn't think was that bad... my estimate of $23K was off by 130 percent.

There is also an extensive forum thread here on BP on using Pex for plumbing, it expands when water freezes, helping to prevent breaks.

If a legit problem that was big (electrical, plumbing, pool, AC, foundation, etc) came up, I would totally go back to re-negotiate.

The HUD inspection report looked favorable but after the house set on the market for almost a year, I found out that the roof needed replacement, the plumbing had to be completely redone, the septic tank was bad, A deck was unsafe and had to be removed.

You need to find out who takes care of the common area plumbing, for instance, between the units, and above and below...You NEED to find out for absolutely sure that there are no other liens on this property--other than the hoa dues, and that no fines or back dues are owed.

I spent about $9,000 on rehab (New roof, AC unit, new pex plumbing, etc).

Once I confirm the numbers and validate the deal, trust me, I will ONLY release rehab funds at certain, pre-defined stages, which normally track the permit process; carpentry/framing, concrete, electrical, plumbing, drywall, finish, final CO, etc.#5 - Oh, let's not forget..., What experience level does the borrower have?

If the original wasn't permitted but now you plan to permit, the inspector may require you to expose all the rough electrical, plumbing and HVAC in that room to verify safety and that there are no code violations.

If it is smaller than that, your rehab could very well be less.Is the electrical and plumbing in tact and good (other than minor repairs)?

We have in all of our leases a rule that after the second time of a plumbing back up that is tenant inflected, the tenant pays for the plumbing repairs.