HELOC for bed/bath addition

[Robert Pierce]

Hey- 

I live in Orlando (winter park) and have a 1960s house. Majority of my neighborhood is a 3/2 or 4/2 and recently a lot of flippers are moving in and tearing down the old to build new 2 story 5+ bedrooms or expand the old house outward.

I've been debating using a HELOC to flip my 'Car port' into another bedroom with full bath, house would become a 5/3.

How do I determine if its a viable idea for my neighborhood? I don't want to invest this money to only see minimal returns.