Time was, you could buy a property and in the time it took you to do it up (even badly) you made money because the market was rising so quickly.
My ex is a qualified joiner with building, plumbing and electrics experience. There's not a lot he cant do. Used to buy a house, live in it whilst doing the work, sell - and have a nice lifestyle with a two month travel break. Then start the next. He was never rich.
What skills have you got in understand the market, managing contractors (aka profit eaters) and selling?
Raising funds to start a business is the last thing you should be thinking about to be honest op. You need to either sell your house and downsize, take in a lodger or two and/or get a job. Borrowing more money really really won't help you.