Empty your basement of all storage items, clutter, furniture and accessories. Remove everything from the basement, sort through it, donate and discard what you don’t want and store things you will keep in a temporary storage unit.
Completely clean the entire basement, floor to ceiling, including windows. Vacuum and sweep dirt, dust, cobwebs and any accumulated debris from floors and vents. Use soap and water to scrub floors, windows and any other surfaces such as ledges, baseboards and door frames. Clean and inspect any appliances, including furnaces, washers and driers, water heaters and freezers.
Conduct home tests for mold, carbon monoxide, radon and lead (if your home was built before 1950). Save test results to show construction professionals.
Contract three to five independent construction evaluations of your basement. Request that contractors check the outside of the building, around the foundation, including subsurface down at least 2 feet to look for cracks, dried and loose caulking, holes and any other damage. Do not sign any contracts for work at this point; just get written evaluations of the condition of the space and recommendations for any repairs and improvements.
Make an appointment with your local building and zoning department to review your contractor’s evaluations. Ask questions, take notes and find out about any necessary permits and authorizations for work you are considering, as well as tax implications of improvement projects.
Review the information you gathered from contractors and the building and zoning department and draft a budget for the project. Plan to correct any dangerous situations such as faulty electrical wiring or mold abatement first, whether you do the work yourself or hire a contractor. Consider using professionals for big jobs such as waterproofing or adding plumbing.
Research finished basements, home remodeling and interior design projects to decide how you want to use the space. Considerations include flooring, wall and window treatments, ceilings, built-in storage and specialty-use areas such as a home gym, a workshop or an office area.
Start work in stages, especially if you are doing it yourself, such as laying a ceramic tile floor with radiant heating or installing new windows, unless your budget and tolerance for construction activity allow for an all-inclusive project.