Reno Financing Strategy

Question for anyone who either has experience doing this or finance broking knowledge: How do you finance a series of renovation projects which last say 3 to 6 months each, without getting stung with exit fees. A revolving line of credit would be the most logical solution, but most lenders would like a constant security and then only charge you to substitute the second security. However, if you are renting and do not have a constant security then you cannot keep this facility open, and it may be hard to ensure that the settlement date of your new purchase and completed project coincide each time. Any ideas?