What happens when a builder doesn't follow the ...

as the owner, and you are untill the project is finished, stop the project, demand an anwser, was this approved by you? what were the resons he is given you for the changes? changes by a builder is usually because he has made a mistake, or he is trying to cover up items. if the change is a load bearing wall, then call the citys inforcement officer to see if there will be problems, if there is none there then stop project and allow him to correct unit at his cost. all materials & labor.

but if you make him pay for corrections, he will get you back before the project is over.  

It all depends if your talking about the visual aspect or the construction.

The builder may find that there are kost that rise above the building budget, or that what the archtect has designed has een effect on the construction. The Archtect is the designer, but if the builder chooses to make changes that the client wants. The client is the boss and the architect unless he has certain rights, that are on paper, must also comply to the decision of the client.

Provided the owner has a proper contract and has not approved a deviation from the architect's plan, the builder must re-do the work at his own cost to comply with the plans.