Waterproofing membrane on an excavated foundation

Exterior Basement Waterproofing in Milwaukee

Stop Water Before It Hits the Wall.

Exterior waterproofing protects your foundation from the outside, where the water starts. Basement Specialists digs along the wall, repairs it, seals it and adds new drainage.

  • Since 1981Locally owned & operated
  • Free EstimatesWritten & no-pressure
  • Warranty BackedUp to 20 years
  • Licensed & InsuredFully bonded
  • 4.7 Stars on GoogleFrom local homeowners

Exterior Waterproofing

The Most Complete Way to Keep Water Out

Interior systems manage water after it reaches your foundation. Exterior waterproofing keeps it off the wall entirely. We excavate down to the footing, clean and repair the wall and apply a waterproofing membrane to the outside surface.

A drainage board goes over the membrane to give water a clear path down the wall, new drain tile is set at the footing to carry it away and the trench is backfilled and graded so surface water flows away from the house.

It's a bigger project than interior drainage, and it isn't right for every home. When leaks are widespread, a wall is being excavated anyway or you want to protect a finished basement without opening it up, it's often the best long-term choice.

Excavation along a foundation

How It Works

The Three Layers of Exterior Waterproofing

Waterproofing membrane being applied
Layer 1Waterproofing Membrane

A continuous coating on the outside of the wall keeps groundwater from soaking in.

Drainage board on a foundation
Layer 2Drainage Board

A dimpled board protects the membrane and lets water drain freely down the wall.

Drain tile at a footing
Layer 3Drain Tile & Backfill

New pipe at the footing carries water away, and grading sends surface water off.

What Causes It

When Exterior Waterproofing Makes Sense

It's the right call in a few specific situations.

Widespread LeaksWhen water comes through several walls or large areas, sealing from outside is the most thorough fix.
Wall Repair PlannedIf a wall is being excavated and straightened anyway, waterproofing it at the same time saves digging twice.
Finished BasementsExterior work protects the basement without tearing out finished walls and floors inside.
Old Masonry WallsStone and brick walls that seep everywhere benefit from a barrier on the outside.
Water against a home foundation
Damp stone foundation wall

Warning Signs

Signs You May Need Exterior Work

If interior fixes haven't solved it, the answer may be outside.

  • Leaks on more than one wall
  • Large damp areas, not just cracks
  • A bowing wall needing excavation
  • A finished basement to protect
  • A stone wall that seeps all over
  • Interior fixes that didn't work
  • Water along the top of the wall
  • Soil sloping toward the house

How We Fix It

Our Exterior Process

Excavator digging beside a homeExcavate

Excavation & Wall Prep

We carefully excavate along the affected walls down to the footing, exposing the full height of the foundation. Nearby landscaping is protected where possible, and the work area is kept organized and safe.

With the wall exposed, it's cleaned and inspected up close. Cracks are repaired, deteriorated areas are fixed and, if the wall has moved, it can be straightened and reinforced before waterproofing.

This is the one time you can see the outside of your foundation, so we make sure it's in good shape before we cover it back up.

Wall Straightening
Membrane applied to a foundationSeal

Waterproofing, Drainage & Backfill

The membrane is applied, the drainage board is installed over it and new drain tile is set in clean stone at the footing. Everything is checked before any soil goes back in.

The trench is backfilled in layers and graded so water flows away from your foundation. Downspouts can be extended at the same time to keep the soil as dry as possible.

When we're done, you've got a foundation that's protected from the outside in, the way it ideally would have been built.

Drain Tile Details
InteriorManages water that reaches the wall. No digging.
ExteriorStops water at the wall. Requires excavation.
Sometimes BothExterior on one wall, interior drainage elsewhere.

What to Expect

What to Expect

  1. 1InspectWe evaluate the walls, the leaks and the conditions outside.
  2. 2PlanWe recommend which walls to waterproof.
  3. 3WaterproofWe excavate, repair, seal and add drainage.
  4. 4RestoreWe backfill, grade and clean up.
Technician and homeowner looking at an exterior excavation

Common Questions

Exterior Waterproofing FAQs

Is exterior better than interior?

Neither is better every time. Exterior keeps water off the wall; interior manages it without digging.

Does it mean digging up my yard?

Yes, along the affected walls. We'll explain what's affected and how it's restored.

Can you do just one wall?

Yes. It's often done only on the walls that leak.

Is it good for finished basements?

Often, because the inside doesn't have to be torn out.

Can a wall be straightened at the same time?

Yes, and it's one of the best times to do it.

How long does it take?

Most projects take several days, depending on how many walls are involved.

What Homeowners Say

Trusted by Milwaukee-Area Homeowners

GoogleGoogle Rating4.7Based on 13 Google reviewsRead Our Reviews
“We had Basement Specialists do foundation work for us, they were affordable, completed the work in a timely manner, and did a great job at cleanup. We even had some extra work done around the porch foundation which was reasonable and looks great. We would highly recommend them!!”
Gay H. Google Review
“We have used Basement Specialists a couple of times. They have been simply wonderful to work with. To start with, the office is responsive, and they were easy to schedule with. Dale showed up promptly…”
Elizabeth H. Google Review
“Just had them do foundation work for us. They did a good job, they did put runners down. Even put some on the basement steps, even after I told them they didn't have to…”
Sharon G. Google Review

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Leaks on Every Wall?

Let's Seal It From the Outside.

We'll compare interior and exterior options and give you a free written estimate.

Basement Specialists
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