Building your own multi family question

[Patrick Flanagan]

Hello, 

I’m going through all the steps and making a list of everything I need to do to buy land and build a duplex to 4 plex my self. The only thing I legally have to sub out is the foundation and plumbing(I’m a Electrician)

I don’t know how to estimate the cost of the build. After I have a set of plans(say a duplex). How do I go about estimating the cost of all the lumber needed, roof material, dry wall, siding, flooring etc. 

any advice helps,
thanks Pat