In an upscale bathroom addition, the new bathroom should be at least 100 square feet, and it will feature the same upscale features as an upscale bathroom remodel, with the addition of extending the HVAC system into the new space. If your bathroom is as big as 150-feet, a bathroom remodel can cost a humongous $40,000. For a second-tier, or mid-leveā€¦ Read More