Interior vs. Exterior Basement Waterproofing

Interior. An interior drain tile system runs under the floor along the walls and feeds a sump pump. It lets water reach the wall, then catches it before it crosses the floor. Fixr lists $40 to $120 per linear foot; This Old House puts interior methods at about $3,000 on average.

Exterior. Exterior waterproofing digs down to the footing, seals the wall with a membrane and adds a new footing drain. This Old House lists $7,000 to $15,000 and $20,000 or more for full excavation.

Choose interior when water comes in at the base of the walls or through the floor, and digging outside would mean tearing up a driveway, porch, deck or plantings.

Choose exterior when the wall itself is wet or damaged, you want to protect a finished basement without opening it, a wall is being rebuilt or straightened anyway, or a crack can only be sealed from outside.

Try the cheap fixes first. EPA advises making sure the ground slopes away from the foundation. Extending downspouts and regrading cost far less than either system and sometimes solve a single wet corner.

Older homes. With a median build year of 1954 in Akron and 1955 in Barberton (ACS 2024 5-year), original footing drains may be clogged, which is one reason interior systems are common on older houses.