How do I determine the amount of materials I need. My building supplier has a list but how do I know it is right before I sign off.
2 more suppliers. Use the same materials list ("take off") that came from the 1st supplier for the next 2 suppliers.
Don't get suckered into the "our lumber is better than theirs", because all framing lumber is pretty much the same. Lumber used in new construction is controlled by building codes. All the lumber you will buy from any supplier is all grade marked (every single piece) for quality.
Be sure that the return policies of each supplier are the same as you will have rejects, and "overage".
Be sure you will be able to order small "fill in" orders for "underage" at the same "volume discount" and that there is no charge for any deliveries, including "fill ins" or any small orders for additional materials.
Be sure you are allowed to stagger deliveries (ship as needed) to help prevent job site theft. The competition will help get a good price!
Be sure to read my Building Materials for Houses.