Basement Waterproofing Basics: Protect and Preserve

Start outside

Most basement water is surface water that was never given anywhere else to go. Grading that slopes toward the house, gutters that discharge at the foundation, and downspouts that end six inches from the wall cause more basement damage than groundwater does.

These are the cheapest fixes available and they should always be the first ones attempted.

Then the interior system

Where surface correction is not enough, an interior perimeter drain to a sump with a working pump and a backup power source handles what gets through.

A dehumidifier is not a waterproofing system. It manages humidity in a dry basement, which is a different problem with a different solution.

What to do before framing

Address any existing leaks or drainage issues before remodeling. Once studs, insulation and drywall are in place, finding and fixing the source becomes destructive and expensive.

We inspect grading, gutters, sump and any existing staining before we quote a basement finish, and we correct what we find first.

• Correct exterior grading and downspout discharge.
• Seal and repair foundation cracks.
• Install or verify the sump and its backup.
• Only then frame, insulate and finish.

Materials that tolerate moisture

Even in a dry basement, specifying materials that handle occasional moisture is cheap insurance. Rigid foam against the foundation rather than fiberglass, treated bottom plates, and flooring rated for below-grade use.