Bathroom Remodeling in Frederick, MD. Discover the art of bathroom design remodeling at J T Hartman Contracting llc. Transform your space with our expertise in master, large, small, and modern bathrooms.  J T Hartman Contracting llc is a full service custom bathroom remodeling company providing high quality expert bathroom renovations since 1999. J T Hartman Contracting llc provides new primary bathrooms, master bathrooms and more.