Structuring a commercial building deal

[Rich Hupper]

I am looking at purchasing a commercial building which is only partially in service. The ground floor level of the building has two restaurants. One is leased and active the other is not. The 3 upper levels of the building is unfinished space roughly 12000 SF. This could be finished off as residential rentals. 

The seller will agree to hold the paper and I will only need to come up with 25% of the purchase price. However where do I get money for the rehab? Whoever lends me money will want a security interest in the property. However the sellers note will be in first position. Would construction money lender ever lend in second position? 

Or should I forget about the seller financing because I do not have the cash for the rehab?

Thank you.