Average cost of rehabs

[Kody Ward]

Hi everyone. I am in the Saint Louis, MO market and am wondering if any of you have come up with an easier way of getting an estimated rehab cost on a house? I'm a painter so I have an idea about construction costs, ish, but I also know if I estimate rehab to be $10/sqft and it ends up being $15/sqft I'm losing out on a lot of money. I know the most accurate way would be to get a contractor into the house to give an estimate, I'm just wondering if anyone has found a somewhat accurate way to figure it out yourself?