I have an idea on how we might be able to acquire another duplex but would love some advice. Since I'm a newbie I'm not sure if this would work. Has anyone done something similar? 

We bought our first duplex. We are living in half and have the other unit on Airbnb (which is going really well!) 

We renovated the Airbnb unit ourselves and are currently renovating the unit we are living in, with hopes to eventually buy another property and rent out both.

 The duplex needs some work we need to hire out: a new roof ASAP, and we'd love to get new siding and new windows. We can at the moment pay cash for the roof and maybe the windows but I was wondering if this might be the better option: 

Take out a home equity loan or a Home Depot project loan and get all three done (roof, windows and siding) with the hopes that our house would then appraise for much higher so we could refinance with 20% equity and get rid of PMI. Then our mortgage payment would be lower but we would acquire a new payment for the home equity loan that would likely cancel it out. But would that open us up to then being able to buy another property and we'd still have our cash on hand for a down payment on an FHA loan. Is this a viable option? Would love any advice! Thanks.