Building a crawlspace foundation, how to know where put piers?

[Lior Golan]

Hey,

I am in a middle of a flip right now and one piece of the project is to do a crawlspace because of an extension.

I have hired a concrete company to do it. They have already poured the concrete "borders" of the extension to get ready for the bricks around. But when I asked him how much and where he is going to put the piers, he said that he needs a foundation plan.

But the problem is that I have already pulled a building permit for the extension and they have requested only a site plan.

What would you suggest me on doing? Should I go and try to pay for the foundation plan or there are really simple rules for that which I can learn really quick to tell him where to put the piers?

Thank you