Hello everyone who will find some time to read my post. I am very thankful in advance to everyone who will try to help me move step forward in my real estate career. 

As of right now i own 4 rental units. I have bought 3 houses in last 2 years and spent all my savings. I have a house that is on double lot. Its an old houses that i am currently renting and produces me $200 in cash flow. Its in good location and if i would be able to knocked it down and build two separate houses with basement suites i would be able to make a big step forward in my career. House still has a mortgage and in order to demolish it i need to pay of mortgage. Than i would be able to use land as a downpayment and get the mortgage to build new houses. Unfortunately i dont have $140K to pay it of. 

I tried to contact few builders but they are not willing to pay if of for me and be ablo to earn themselves more business with building 2 new houses.

Any advise i would really appreciate

Thank you!