Marklein Builders, Inc. is a Custom Home Builder & Property Developer Building Quality Homes in Janesville for over 45 years. Our services include the following: CUSTOM HOMES, new home building and remodeling, room additions and garage additions; REMODELS, rec-rooms, kitchens and bathrooms; CONCRETE, concrete slabs, driveways, flatwork, foundation work and basement repair; and LAND DEVELOPMENT, sale and development of lots, subdivisions, real estate sales, own and manage rental properties and build and manage condominiums.