It is best if you can include both in the process early. Architects will be able to put your ideas on paper and create a plan in moving forward. Your contractor can help make sure the design stays within your budget and cost-effective design alternatives. Good luck with your project.

An architect would be able to provide you with an overall vision and come up with a set of floor plans / elevation / details drawings so the contractor could price out the project.

Want to add something to your already existed home? Consult your architect, it may not look good after addition. Take help from experienced ones.