I hope you are aware that there will be a cost related to removing the uninhabitable structure. Were I to offer to buy the property, I would require that the seller remove it, and offer no more than the value of the land plus the added value of any utilities in place.
As for your financing options, you will need interim financing while you build. There's nothing typical about rates or terms. Your best info will come straight from a lender. Shop around. Talk to your bank first, and then with a mortgage banker/broker.
There are loan products that will allow you to start as a construction loan and convert to a mortgage once you have completed the project.
Please let mek now if you need additional resources to help in this area.
Ritch Haenke, Realtor(r)
Coldwell Banker, United Realtors
You will need special financing for this property. Best to check with local banks. Tell them what you want to do and your timeframe for doing it and they can give you the best options. Be prepared to put a significant amount of money down...something like 30-50% on the lot. Another idea is go directly to the builder. Let them buy the lot for you on their line of credit.