My house is from the late 1990s. Why does the crawl space already have a problem?

Because the parts that were installed new have reached the age at which they fail, not because anything was built badly. A house from that era got a vapor barrier, code-required foundation drainage and floor insulation from the start; twenty-five to thirty years later the barrier has torn at the access route and around piers, the perimeter drain may have silted or settled, and the insulation has sagged. There is a fourth cause that is not about age at all: downspout extensions get shortened or removed during landscaping, and once a downspout discharges next to the foundation it will produce water under the house regardless of how new the house is.

Should I fix the downspouts and grading before paying for interior drainage?

Usually yes, and on a Wilsonville house it should at least have been considered before a trench is quoted. Exterior downspout rework and regrading typically runs several hundred to a couple of thousand dollars, against several thousand for an interior perimeter drain and sump. With mostly post-1980 housing and moderately drained ground here, surface water is a more common source than a rising water table. A competent inspection walks the exterior and looks at the discharge points, and you are entitled to ask what it found there before agreeing to work inside the crawl space. There is one order-of-operations reason this matters beyond the money. If surface water is the source and it is not corrected, an interior drain will run continuously and the pump will wear out early doing a job the grading should have done.

Crawl Space Repair in Wilsonville, OR

Wilsonville crawl space repair for Charbonneau, Villebois, and the broader I-5 corridor. Licensed Oregon CCB contractor network, free in-home inspection.

Free Inspection (503) 210-5062

Every inspection, quote, and repair is handled by an independent contractor licensed by the Oregon CCB (or Washington L&I across the river). We do the matching; they do the work.

19 service areas covered

free inspections

Verify any contractor's license: Oregon CCB or Washington L&I

SW Corridor Zone

About Crawlspaces in Wilsonville, OR

Last updated September 28, 2026

Wilsonville is a fast-growing south metro city with a mix of 1970s through 1990s subdivisions, the planned Villebois community (most homes built post-2005), the Charbonneau retirement community, and newer subdivisions throughout. Most Wilsonville homes are newer than the metro average, but the 1970s and 1980s stock in Old Town and along Day Road shows the typical Westside-corridor aging pattern.

The Tualatin River and its tributaries run along the northern edge of Wilsonville, and low-lying ground near a river generally carries a higher winter water table than land above it. Most newer Wilsonville homes have code-compliant perimeter drainage; older homes and properties closer to the water more often need a drainage retrofit. A contractor can tell you which category your lot falls into during the inspection.

Common Wilsonville scopes include vapor barrier replacement, rim joist sealing, and targeted drainage work. Real estate transaction work is common here, and it is worth telling the contractor about a closing date at the inspection rather than after the quote.

ZIP codes covered 97070

Neighborhoods Charbonneau, Villebois, Old Town Wilsonville, Day Road area

Licensing body Oregon CCB

Wilsonville sits in the SW Corridor service zone and straddles the Clackamas and Washington county line. Contractors are Oregon CCB-licensed.

Local Conditions

Almost no old housing, which settles most of the question

Wilsonville has the second-smallest share of pre-1980 housing on this site. Census American Community Survey five-year estimates for 2019 to 2023 give a median year built of 1998, with 14.4% of homes built before 1980 and 1.7% before 1950.

Nearly nine in ten Wilsonville homes were built after 1980, which removes almost every high-cost finding from the table before an inspection starts. There is essentially no post-and-pier framing here, essentially no crawl space that never had a ground cover, and very little sub-two-foot clearance. A house built in 1998 got a vapor barrier, code-required foundation drainage and floor insulation as part of the original build.

What that housing has instead is twenty-five to thirty years of wear on all three. Barriers tear at access routes and around piers. Perimeter drains silt up or settle. Downspout extensions get shortened or removed during landscaping and start discharging at the foundation, which is the single most common avoidable cause of water under a newer house.

The reason this matters commercially is that Wilsonville is a place where an expensive scope should be justified specifically rather than by reference to metro norms. If a quote here sits near the top of the published encapsulation range, the burden is on the contractor to show the condition driving it, because the town-wide housing profile does not supply one.

Middling ground, and the exterior fix that often beats the interior one

USDA soil survey data clipped to the Wilsonville place boundary rates 39.2% of the mapped area as somewhat poorly, poorly or very poorly drained, with 3.2% unrated. Middling for this metro: above West Linn and Tualatin, below Beaverton and Gresham.

Combined with the housing profile, that points somewhere useful. On a newer house with functioning original foundation drainage, on ground that is only moderately water-holding, water at the crawl space is more often arriving from the surface than from the water table — roof runoff discharged too close to the foundation, negative grade from settled landscaping, a failed area drain.

Those are exterior problems with exterior fixes, and they are an order of magnitude cheaper than interior drainage. Downspout rework and regrading typically runs a few hundred to a couple of thousand dollars against several thousand for an interior perimeter drain and sump. Any competent inspection here should have walked the exterior and looked at the downspouts before recommending a trench inside the crawl space, and you are entitled to ask whether it did.

Everything through one office

Wilsonville issues all its own permits — building, mechanical, plumbing and electrical — with none routed to Clackamas County. That is the simpler arrangement, and it is not universal in this county: Happy Valley, West Linn and Oregon City all send electrical plan review and inspection to the county while handling the rest themselves.

Worth confirming with any contractor who works mainly north of here, since the process they are used to may not be the process that applies.

Where the river actually matters here

Wilsonville straddles the Willamette, and Charbonneau sits on the south bank in a position no other neighbourhood on this site occupies. The FEMA Flood Insurance Study for Clackamas County covers the city and studies the Willamette in detail; the river's largest historical floods were 1861 at roughly 590,000 cubic feet per second and 1890 at about 510,000, with December 1964 at 403,000 the largest of the modern record.

For the great majority of Wilsonville houses this is irrelevant to the crawl space. The city's dominant pattern, set out above, is a post-1980 house on moderately drained ground where the water arriving under it came off the roof rather than out of a river. Flood exposure is an address-level question answered by the FIRM panel, and it applies to a small minority of the city.

Where it does apply, it changes the design rather than the diagnosis: a crawl space that can take surface water needs a way for that water to leave and equipment sited above it. That is a different conversation from the downspout-and-grading fix that solves most Wilsonville complaints, and the two should not be conflated in one quote.

Sources for Wilsonville

United States Census Bureau, American Community Survey 5-Year Estimates — Year Structure Built (B25034) and Median Year Structure Built (B25035) (ACS 2019–2023 5-year estimates, tables ACSDT5Y2023.B25034 and ACSDT5Y2023.B25035) Open dataset
USDA Natural Resources Conservation Service, Soil Survey Geographic Database (SSURGO), via Soil Data Access (muaggatt.drclassdcd — drainage class, dominant condition) Open dataset
Clackamas County, Building Permit Responsibility by Jurisdiction
Federal Emergency Management Agency, Flood Insurance Study: Clackamas County, Oregon and Incorporated Areas (FIS 41005CV001B, countywide effective 17 June 2008, revised 18 January 2019)

Sources last checked between August 28, 2026 and September 28, 2026.

Services

What Wilsonville's Figures Point To

On the Census and soil-survey figures behind this page, Wilsonville sits above the metro median for wet-rated soil: 39.2% of its mapped area, against 26.4%. Its housing has a 1998 median build year with 14.4% predating 1980, and on stock that age a ground cover is usually already down there, so the first question is normally where the water comes from rather than the barrier.

Every crawl space repair service on this site, in the order Wilsonville's figures point to:

Or work back from a symptom: standing water, high humidity, sagging or bouncy floors, or any of the others. If none of it narrows things down, what a crawl space inspection covers sets out how a contractor gets from a symptom to one written scope, and what to ask before accepting it.

Pricing here is the metro-wide modelled range, not a Wilsonville figure: drainage $3,825 to $6,800, vapor barrier $3,225 to $4,425, encapsulation $10,100 to $12,325. The cost guide shows what moves a bid above or below those. Floor and rim joist insulation are the parts of this work an Energy Trust incentive can pay toward; the 2026 rebate guide has the amounts and the existing-insulation limit.

Nearby Areas

Crawl Space Service Near Wilsonville

Questions, Answered

Wilsonville Crawl Space FAQs

: Because the parts that were installed new have reached the age at which they fail, not because anything was built badly. A house from that era got a vapor barrier, code-required foundation drainage and floor insulation from the start; twenty-five to thirty years later the barrier has torn at the access route and around piers, the perimeter drain may have silted or settled, and the insulation has sagged. There is a fourth cause that is not about age at all: downspout extensions get shortened or removed during landscaping, and once a downspout discharges next to the foundation it will produce water under the house regardless of how new the house is.
: Usually yes, and on a Wilsonville house it should at least have been considered before a trench is quoted. Exterior downspout rework and regrading typically runs several hundred to a couple of thousand dollars, against several thousand for an interior perimeter drain and sump. With mostly post-1980 housing and moderately drained ground here, surface water is a more common source than a rising water table. A competent inspection walks the exterior and looks at the discharge points, and you are entitled to ask what it found there before agreeing to work inside the crawl space. There is one order-of-operations reason this matters beyond the money. If surface water is the source and it is not corrected, an interior drain will run continuously and the pump will wear out early doing a job the grading should have done.

Ready to Fix Your Crawlspace?

Get matched with a licensed local contractor - Oregon CCB, or Washington L&I across the river - for a free in-home inspection, with no obligation.