Any good resources for determining repair costs?

[Samantha Carcione]

Hi, I'm a new appraiser in NYC. The jobs I've been getting lately have included a lot of homes in fair to poor condition some needing full gut renovations. Finding reliable comps has been difficult, as most of these sales are not marketed. I mostly work in Queens. Does anyone know of any good resources I can use to determine contractors costs in my area? I know prices range, but I just need to get an idea of how high a buyer can bid for a deal to be profitable.