Method comparison
Exterior excavation vs interior drain tile
The same wall, two scopes, roughly double the price. Here is when the expensive one is the right one.
Every Metro East waterproofing bid eventually comes down to this fork: relieve the pressure from inside, or stop the water outside. The clay under this region pushes the decision one way most of the time, and the price gap is the reason.
| Scope | Typical Metro East bid range |
|---|---|
| Interior drain tile, full perimeter | $6,000 - $12,000 |
| Exterior excavation and membrane, one wall | $9,000 - $18,000 |
| Exterior, full perimeter on a walk-out lot | $22,000 - $45,000 |
| Landscape, deck or driveway restoration after a dig | $1,500 - $9,000 |
Is exterior excavation better than interior drain tile?
Short answerNeither is better in the abstract. Exterior excavation stops water at the outside face of the wall, which is the only fix for a wall that is failing structurally or leaking above grade. Interior drain tile relieves the pressure under the slab, which is what stops the water Metro East clay pushes at your footing.
Why does exterior work cost so much more in Metro East clay?
Short answerBecause the crew has to move the same heavy shrink-swell clay twice, on both sides of the footing, and then restore whatever sat on top of it. Expect $9,000 to $18,000 for a single wall, against $6,000 to $12,000 for a full interior perimeter.
Which fix do Metro East contractors recommend most often?
Short answerInterior drain tile, for the ordinary case of water appearing at the floor-wall joint after heavy rain. Exterior excavation gets recommended when there is a structural wall problem, a failed exterior membrane on a newer build, or a finished basement you refuse to cut.
Can you do exterior work on only the wall that leaks?
Short answerYes, and in Metro East that is the normal shape of the job. Water usually comes from the uphill or downspout-loaded side, so a one-wall dig is common. Ask what happens to the landscaping, the deck footings and the driveway edge before you sign.
Does exterior excavation void the interior system's warranty?
Short answerIt does not, but running both means two warranties from possibly two crews. If you expect to do exterior work later, tell the interior contractor now so the tie-in points are left accessible instead of buried under fresh concrete.
What if the wall is bowing, not just wet?
Short answerThen drainage alone is the wrong first question. A bowing or cracked wall needs a structural evaluation before any waterproofing scope is priced, because carbon fiber, anchors or piering change where the drainage has to go.
Have both priced
The honest way to choose is two written scopes on the same wall. We will route you to a contractor who quotes both instead of only the one they prefer to sell.
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