Interior-based waterproofing methods, often called “negative side” projects, involve moving out water that’s inside the home. Fixing a water problem from the inside may be a cheaper option, especially in cases where exterior work isn’t practical or possible.
Drain: This system moves water out of the house through a hole or trench in the foundation, paired with a sump pump. Such a system should also include insulation of basement walls, with a vapor barrier to protect against condensation. Drainage systems start at around $2,000. The national average cost of installing a French drain, including exvacation and sump pump, is between $7,100 and $9,700 according to Bluebook International, but may be more or less depending on where you live. Search prices in your local area at the Angie’s List Bluebook Pricing Guide.
Sealants: Some highly rated waterproofing companies don’t recommend sealants because they say they fail too easily. The cost of a sealant-based waterproofing project may range from $4 to $8 a square foot.
Epoxy injection: Like sealants, this option is not always favored because it may provide only a temporary solution to fill cracks in poured-concrete walls. Epoxy injections can start at $300.