Pittsburgh Exterior French drains

Exterior French drains Pittsburgh

An exterior French drain intercepts water outside the house, before it ever reaches the foundation wall. Depending on the problem, that means a shallow trench drain running across a slope to catch surface runoff, or a full footer drain excavated down alongside the foundation, set in washed stone against a waterproofed wall, and pitched to a daylight outlet or dry well. Either way the principle is the same: cut the water off upstream instead of managing it after it’s already inside.

On Pittsburgh’s hillside lots this is often the highest-value drainage work you can do. A house set into a slope in Mount Lebanon, the South Hills, or Squirrel Hill is collecting everything the grade above it sheds, and no amount of interior work changes that volume. An exterior drain across the uphill side, combined with regrading and downspouts piped well past the foundation, reduces the water load on the structure rather than just relocating it.

Exterior systems also protect things an interior drain can’t. Water saturating the soil behind a retaining wall builds hydrostatic pressure that makes walls lean and bulge, and it’s the reason so many walls in this region fail early. Saturated base material under a driveway or patio heaves and cracks the slab once winter freeze cycles start. Drainage behind walls and under new concrete is part of how we build both, and it’s frequently what’s missing on work we’re called in to repair.

The trade-off is access. Excavating along a foundation means opening up landscaping, and sometimes working around a driveway, deck footings, or a tight side yard between houses. We walk the site first, confirm where the water is actually coming from, and tell you whether an exterior drain, an interior French drain, or a combination gives you the better long-term result.