if you are not experienced, You may want to hire a buyer broker, you can usually do so at no cost to you, they get paid their commission from the fee advertsised in MLS by the listing agent and paid at closing.
Good luck with your offer.
Value is dependent upon LOCAL market conditions. Why not call a local Realtor to assist? It costs you nothing - and you can get professional advice and information in order to make an informed decision on what the offer amount should be.
Licensed in Maryland, Virginia and D.C.
As a mortgage lender, I can tell you that on an owner occupied residence, there are some programs still available for a purchase / construction rehab type deal. You will need a 10-20% down payment based off the after repair value & credit worthiness. It sounds like your scenario may fit that bill. If you plan on living in the home and want more information, I'm happy to help.
Southwest Funding - Integrity
UNLESS cash offer no lender would approve loan unless roof is repaired, questionable about the permits.
Sounds like a headache recommend move forward search for another home UNLESS you have plenty cash out of your pocket do all required repairs
Lynn911 Dallas Realtor & Consultant, Loan Officer, Credit Repair Advisor
The Michael Group - Dallas Business Journal Top Ranked Realtors
Our recommendation is to place some importance upon the activity in the local market before factoring in the property's personal appeal. An offer of $120,000 would be most feasible if you were able to support it with solid information that you can present to the seller with your offer.
There is no direct answer anyone here can give you for this. The only answer is to have a knowledgeable agent inspect the home, investigate comparables and tell you what the value range is. The value 10 years ago or 10 months ago are irrelevant to what the value is today based on current data.
If you are not working with a solid agent, find one. If you need a referral, consider NM agents who answer or send me an email and I can recommend a couple to consider.
One more note, with all the non-permitted work that's been done, don't go cheap on inspections. Have it looked over high & low inside & out. My favorite inspector uses infrared technology to find hidden issues. Some inspectors charge more, and it's worth it for a home like you're describing.
Financing will be another issue, make sure you can get a loan for a home in this condition. Talk to your lender about an FHA 203k rehab loan. Best of luck.