This is a different relationship than most people have with a contractor. The home design contractor is a trusted member of the team. He gives his input during the design process and based on his knowledge of construction and what really happens on construction sites he contributes valuable information to tweak the design in order to maintain the budget. It is a powerful collaborative effort.
During this process you will become more educated about the impact of each decision you make and how they affect the overall cost of the project. You will be pushed to think through details and make decisions early in the process. This is one of the best ways to control the dreaded “budget creep”!
Additionally the home remodeling contractor will be able to let you know what alternatives are available and how they can affect both cost and design. As an example, suppose you are adding a deck outside your kitchen and also want French doors that will open onto the deck. The initial design idea shows a door which will have to be custom made, with transom windows above. The contractor’s preliminary estimate on the deck and door work is more than your budget. However, by collaborating with the contractor it is determined that a simpler stock French door unit will significantly lower costs. As you can see, the contractor is working with you to create a project that call be built within your budget but still satisfy your desires.
Another significant point to consider is that you and the contractor will have developed a good working relationship. All too often in a competitive bid environment the potential exists for a design professional to be aligned with the owner against the contractor in an adversarial relationship. When all parties involved work together on the project from the start this is much less likely to happen.