Waterproofing for Tigard Basements and Crawl Spaces

Groundwater, Clay and Creeks in Tigard

Fanno Creek winds through Tigard in a shallow valley, and the houses at the bottom of that valley share the ground with it. Meanwhile, the slopes of Bull Mountain to the south shed rain downhill toward those same low streets, so water arrives from above while the creek keeps the ground below saturated.

That sets up two kinds of wet. In the valley, a high water table pushes into basements and crawl spaces from underneath. On the Bull Mountain side, runoff flows across yards and presses against uphill foundation walls. Both sit on clay, which drains slowly and holds water for weeks.

Housing varies widely. Ranches and split-levels from the 1960s through the 1980s are common, many on crawl spaces, and newer subdivisions have crept up the hillside with partial basements. Each foundation type fails its own way, but the cause is the same: more water around the house than the ground can carry off.

That variety is why two houses in the same neighborhood can need opposite fixes. One has a wet basement because the footing drain is clogged, and the next has standing water under the house because the lot is flat and the pump was never installed. A Tigard waterproofing contractor has to read the lot before reading the quote.

Basement and Crawl Space Repairs We Handle Most Here

Most calls fall into one of the jobs below.

Crawl Space Waterproofing

Low ground near Fanno Creek often leaves crawl spaces with standing water in winter. We install perimeter drainage and a sump pump so water leaves the space instead of sitting on the soil. Read about crawl space waterproofing in Tigard.

Crawl Space Encapsulation

After the water is handled, a sealed liner on the floor and walls and a dehumidifier stop the damp air and the musty smell that rise into the house. Our crawl space encapsulation page covers it, and a crawl space vapor barrier is the lighter option for a drier space.

French Drain Installation

For homes below Bull Mountain, a French drain across the uphill side of the lot intercepts runoff before it reaches the house and sends it to a safe discharge point.

Sump Pump Installation

Where groundwater rises to the foundation, a sealed basin and pump remove water as it collects. Sump pump installation includes a battery backup, because winter storms often bring power outages.

Foundation Crack Repair

Hillside homes can move slightly as soil shifts, and cracks leak when the ground is wet. Foundation crack repair by injection with epoxy or polyurethane from inside closes them through the wall. See foundation crack repair.

For the homes that do have basements, basement waterproofing in Tigard follows the same pattern: interior drain tile along the slab edge, a sealed sump and a sealed wall where the water is entering. A wet basement or a leaking basement here usually responds well once the drain and pump are in place.

Winter Groundwater and Your Crawl Space

October rain soaks soil that has dried out over the summer, and by December the valley floor and the slopes above it are saturated. Fanno Creek runs higher through the winter, and the water table beneath nearby streets follows it up.

In January and February, homes in the lowest blocks see damp crawl spaces, seepage at basement floor joints and sump pumps that rarely stop. Hillside lots see water running across the yard after each storm and pooling beside the uphill wall.

The ground stays wet into spring. A crawl space that was damp in December is still damp in April, and the framing has had months to absorb moisture. Work in late summer is easier and finishes before the first storms.

Between storms, the ground drains slowly. Clay near the creek holds water for days, and hillside soil releases runoff downslope for hours after rain has stopped. That means a basement can seep long after the weather clears, and a crawl space can be wet in the morning after a night of dry weather. A system that handles both shallow runoff and groundwater is the one that holds up.

A site visit covers the crawl space floor and vents, the basement walls and floor joint, the downspouts and gutters, the grading, and the place a drain could discharge. We take moisture readings and photographs, and we show you what we found before we talk about the work.

It also pays to think about the sequence. On a hillside lot with a crawl space, the order of work matters: intercept the runoff above the house first, then drain the crawl space, then seal it. Doing it the other way around puts a new liner under a trickle that still arrives from the slope, and the liner ends up holding water instead of keeping it out. We lay out the steps so you can see why each one comes when it does.

Valley-floor homes follow a simpler rule. When the creek-fed groundwater is the main source, the pump and drain carry most of the load, and grading and gutters are the finishing touches. A basement or crawl space that fills fastest during the first big storm of the year is usually telling you where the low point is, and that is where the basin goes.

Around Tigard and Nearby Towns

Tigard work ranges from the streets near Fanno Creek Park and Summerlake to the homes along Hall Boulevard, around Pacific Highway and up the slopes of Bull Mountain. Properties near the creek see the highest groundwater, and the hillside streets south of Bull Mountain Road see the heaviest runoff.

Our waterproofing services in Tigard also cover the older ranch tracts where short crawl spaces and flat lots make standing water under the house a regular winter event. Many of those houses have never had a drain, and the first sign is often a musty smell in the hall closets.

Across the line we also work in Tualatin and Lake Oswego, where clay soil and wet winters create similar problems.

Some homeowners ask whether they can wait one more winter. If the water is only a damp patch and the smell is faint, a year may not change the repair. If there is standing water, soft framing or a pump that never shuts off, waiting adds cost, because wet wood and wet insulation have to be replaced along with fixing the water. A short call in September costs nothing and tells you which case you are in.