How do I calculate ROI for other Investors besides myself

[Jonathan Ockletree]

Hello everyone. Im from Indianapolis, IN and i'm looking into my first investment property but the issue is this. It needs some construction work, probably around 12-15k range. I don't have the credit to get a construction loan but I do know some people with a nice amount of cash. How do I calculate out a loan from them that actually works and what's typical? What have you guys seen done when calculating out private money loans that typically work for both parties? Even if there is another post somewhere that someone can point me out to any help will be greatly appreciated! 

If you need the info. 

getting the house from family member for $4500 its ARV is 44k . Area rents for around $700.00/mo

Buy and Hold