Giving contractor a % of profit?

[Barbara Long]

I've always used contractors here and there and paid up front. But has anyone ever gave their contractor a % of profit after the property has sold? Like, paying for the material then once the house sells give your contractor a %?

I am meeting with my cousin to sorta partner up. I purchase and he renovates, but I"m thinking he wants me to purchase the material ?

If you have done this before please comment. I don't know really know where to start...

Is there a formula for this?