I want to replace my living room, dining, and kitchen all with 12mm thick laminate. My kitchen and dining room already have 3/4" hardwood installed original to the house, Including under cabinets and appliances. Carpet is in the living room. To keep the entire floor level, do I need to remove the hardwood floors first? If so, do I also remove them where the refrigerator and oven sit? I want a smooth transition and not sure how to handle existing hardwood floor.