Is an interior or exterior French drain better for a wet basement?

It depends on the water source. An exterior French drain is better for intercepting groundwater before it reaches your foundation, while an interior French drain is more practical for managing water that seeps through the cove joint or up through the floor slab. For existing homes where exterior excavation is impractical, an interior system with a sump pump is the most common and effective solution.

How much does a French drain cost to install around a house?

An interior French drain typically costs $4,000 to $12,000 for a full perimeter installation, while an exterior French drain costs $8,000 to $25,000 or more. Costs vary based on foundation depth, soil conditions, linear footage, and regional labor rates. Exterior systems cost more due to the heavy excavation and landscape restoration required.

How long does a French drain last?

A properly installed French drain with quality materials and filter fabric can last 25 to 40 years. However, interior systems include a sump pump that typically needs replacement every 7 to 10 years. The most common cause of premature failure is clogging from improper gravel, missing filter fabric, or root intrusion.

Can I install a French drain myself?

An exterior French drain around a foundation requires heavy excavation equipment and is not a practical DIY project. A shallow exterior French drain in a yard (not at footing depth) is possible for experienced DIYers. Interior French drains involve cutting concrete, working below the slab, and installing a sump pump — this is best left to professionals to ensure proper slope, waterproofing, and code compliance.

Does a French drain need a sump pump?

Interior French drains always require a sump pump because the water has no gravity outlet — it must be pumped up and out of the basement. Exterior French drains may not need a sump pump if the pipe can daylight (exit at ground level) on a downhill slope away from the home. If the exterior drain cannot achieve daylight, it also requires a sump pump.

What is the difference between a French drain and a curtain drain?

A curtain drain is a type of French drain installed in the yard uphill from the home to intercept surface water and shallow groundwater before it flows toward the foundation. A French drain installed at the foundation footing level is typically called a footing drain or perimeter drain. Both use the same perforated pipe and gravel system, but they serve different purposes and are installed at different locations and depths.

Interior vs. Exterior French Drains: Which Solves Your Problem

Compare interior vs. exterior French drains to find the right solution for your water problem. Learn costs, installation, and when each type works best.

By Low Point Labs

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