Excavation to the footing, membrane, drainage board, and new weeping tile — the most thorough fix there is, and the most expensive one, for good reason.
Exterior waterproofing stops water before it reaches the wall. A crew excavates all the way down to the footing, cleans and repairs the foundation wall, applies a waterproof membrane, adds a drainage board to protect the membrane and channel water down, installs new weeping tile at the footing, and backfills — ideally with stone and soil that drains, not the clay that came out of the hole. It is the most complete answer to a wet basement, and it costs roughly twice what an interior system costs, because the digging is most of the job.
Full exterior systems typically run $10,000–$18,000, with excavation priced at roughly $150–$350 per linear foot. The range moves with depth of the foundation, access for equipment, and what sits over the excavation line — decks, steps, driveways, and landscaping all add digging cost and restoration. A partial excavation (one or two walls) costs less and is often the right call when only one side of the house leaks.
Exterior excavation on a very old stone or rubble foundation needs care — removing the soil that braces a fragile wall can cause movement, and a contractor who has not worked on old Connecticut stone should say so. It is also the wrong first step when the problem is surface water: gutters, grading, and downspout extensions cost a fraction of excavation and should be fixed first. And it is a fair-weather job — deep excavation in frozen ground is slower and more expensive, which is one reason interior systems dominate winter work.
Restoration is part of the quote, not an afterthought. Backfill, grading, and landscaping restoration should be itemized. The cheapest exterior quote is often the one that leaves you re-seeding, re-planting, and re-grading on your own dime.
Two minutes. Matched with a local waterproofing contractor. Free written estimate, no obligation.