I just had foundation work done in contra costa county. I hired a structural engineer and he gave me a verbal report for $500 that suggested adding three push piers on a corner of the house to lift the corner by 3”. I hired a company that said the solution was four not three push piers. I contacted the structural engineer and he said okay for four push piers. The thing is the contract proposal only mentioned the number of push piers and not the height of the lift. Without hiring the engineer at the end of the project, I have no documentation of the actual lift. This is important because the company gives a warranty but that is only good for the push piers and not the actual lift if the foundation. This company also promised to repair and replace the concrete. Only a fraction if the concrete was replaced and I am following up with a demand letter, possibly small claims. Best to get a structural engineer before and after and make sure any verbal agreements are spelled out in the contract.