Foundation Waterproofing in Portland, Oregon
Portland's climate puts your foundation under constant moisture pressure. A&N Construction and Excavation provides foundation waterproofing services that protect your home's structural integrity and keep your crawlspace and basement dry. We handle the excavation, drainage installation, and waterproofing membrane application that creates a complete moisture barrier.
What Is Foundation Waterproofing?
Foundation waterproofing is the process of applying a barrier to the exterior of your foundation walls to prevent water from penetrating into your basement or crawlspace. The process typically involves excavating around the foundation to expose the walls, cleaning and repairing the concrete surface, applying a waterproofing membrane (liquid-applied or sheet membrane), installing a drainage board, and connecting a French drain or footing drain to carry water away. This is different from dampproofing (a thin tar coating) — full waterproofing creates a continuous barrier that handles both moisture vapor and hydrostatic water pressure.
Our Foundation Waterproofing Process
- 1
Assessment
We inspect your foundation for signs of water intrusion, cracks, and deterioration to determine the scope of work needed.
- 2
Excavation
We excavate around the foundation perimeter to expose the walls down to the footing. This is typically 6-8 feet deep.
- 3
Surface Preparation
We clean the foundation walls, repair cracks and spalls, and prepare the surface for membrane application.
- 4
Waterproofing Membrane
We apply the waterproofing system — liquid-applied membrane, sheet membrane, or both — per manufacturer specifications.
- 5
Drainage Board
We install a dimple board or drainage mat over the membrane to protect it from backfill damage and provide an additional drainage plane.
- 6
Footing Drain
We install a perforated drain pipe at the base of the footing, surrounded by washed drain rock, to collect and redirect water.
- 7
Backfill
We backfill with clean material in compacted lifts and restore grading to slope away from the foundation.
When You Need Foundation Waterproofing
Your crawlspace or basement has persistent moisture, standing water, or flooding. You see white mineral deposits (efflorescence) on your foundation walls. There are visible cracks in your foundation that leak during rain. Your home has musty odors from below-grade moisture. You're building a new home and want to protect the investment from day one.
Foundation Waterproofing Cost in Portland
Foundation waterproofing is a significant investment — and one that pays for itself by preventing structural damage. For a standard residential foundation (100-150 linear feet of perimeter), expect costs of $8,000 to $20,000+ depending on depth, access, soil conditions, and the waterproofing system used. Partial waterproofing (one or two walls) costs proportionally less. We provide detailed estimates and explain exactly what's included.
Why Choose A&N
Foundation waterproofing requires deep excavation next to your home — this is not a DIY job or a project for an inexperienced contractor. We've done foundation waterproofing across Portland, working carefully around landscaping, utilities, decks, and tight property lines. We coordinate with waterproofing membrane installers and ensure every component of the system is installed correctly.
Foundation Waterproofing Service Areas
We serve the entire Portland, Oregon metro area.
Frequently Asked Questions
What's the difference between waterproofing and dampproofing?
How long does foundation waterproofing last?
Can you waterproof just one side of my foundation?
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A&N Construction and Excavation · CCB #268549