Waterproofing for Cedar Mill Basements and Crawl Spaces

Where Water Gets In Around Cedar Mill

Drive up almost any street off Cornell Road and the lots tilt, with a front yard that sits a full story above the back, and that slope decides where the water goes. Rain runs downhill across the yard, collects against the uphill wall of the house and works its way into the basement behind it.

Much of the area was built in the 1960s and 1970s, and a lot of those houses are daylight basements: the back of the house is a full floor at grade, the front is buried. That buried wall carries the weight of a wet hillside. Cedar Mill Creek and its small tributaries drain the neighborhood, and the runoff from the slopes above keeps the soil saturated well into spring.

Homeowners usually notice it first at the uphill wall: a damp band, white crust on the concrete or a leaking basement that only appears after three days of rain, not one. The soil is clay, so water that gets into it does not leave quickly. A Cedar Mill waterproofing contractor starts by walking that uphill wall after a storm and seeing where the water beads.

Split-level homes add a second spot. Under the buried section there is often a short crawl space, and in wet winters it collects standing water under the house while the finished rooms above stay perfectly dry. The first sign is a musty smell in the downstairs hall, and by then the insulation has usually been damp for months.

What October to May Does to a Foundation

October storms soak hillside lots quickly, because the slope sheds water faster than the soil can absorb it. By December, the ground behind the house is saturated, and each new rain adds flow to the same drainage paths. Water that used to disappear into dry soil now rides on top of it.

The creek and the smaller drainages carry that water downhill. Homes at the bottom of a slope collect the runoff from several lots above them, and their basements see the most water. In a long wet spell, the uphill wall of a daylight basement can seep for weeks.

The wet persists into April. Foundations that dry out slowly are the ones where mold shows up on stored items and on the bottom of finished walls. Walls under that kind of load also move a little each year, and cracks open where the load changes. Doing the work in summer, when the slope is dry and trenches stay open, puts you ahead of the season.

A site visit covers the uphill wall and the floor joint, the grading above the house, the downspouts and gutters, the crawl space under any split-level section, and the place a drain or pump could discharge. On steep lots we also look at where the neighbors' water goes, because it often ends up in the same trench.

What Usually Solves the Problem Here

The fix depends on which side of the house the water comes from, and how much of the wall is already finished inside.

Exterior Waterproofing

On a daylight basement, the buried wall is the one that fails. Exterior waterproofing digs down along it, seals the wall with a membrane and lays a new drain at the footing, so hillside water runs around the foundation instead of through it. Where a deck or stairs sit in the way, we plan the route before we dig.

French Drain Installation

On sloped lots, a French drain across the uphill side of the house intercepts runoff before it reaches the wall. We route it to a safe discharge point downslope, away from the foundation and the neighbors. Read more about French drain installation in Cedar Mill.

Basement Waterproofing

When excavation is not practical because of a deck or tight side yards, basement waterproofing in Cedar Mill is done from inside. Interior drain tile along the slab edge, with a sealed sump, catches water that gets through and protects finished space that is often a family room or a bedroom.

Crawl Space Waterproofing

For the short crawl space under a split-level, we lay perimeter drain pipe and add a sump pump so water leaves the space. Once it is dry, crawl space encapsulation or a crawl space vapor barrier seals out the damp air. See crawl space waterproofing for the steps.

Foundation Crack Repair

Sloped lots put uneven load on a foundation, and cracks open where the load changes. Foundation crack repair injects the crack from the interior with epoxy or polyurethane, and we check the wall for signs of movement at the same visit.

A sump pump installation rounds out many of these jobs. On lots where groundwater collects at the base of the slope, the pump removes what the drains collect, and a battery backup keeps it running when storms knock out power.

One more note on timing. Hillside excavation is slow and muddy from November through March, and a trench left open in a storm fills with water and slumps. A job planned for late summer runs faster and cleaner, and the new drain has a few weeks to settle before the first heavy rain tests it. Homeowners who call in September get the pick of the schedule; those who wait for the first leak join a crowded list.

Streets and Areas We Work In

Our work here runs from the streets off NW Cornell Road and Saltzman Road to the blocks near Cedar Mill Library and the homes along Barnes Road. Lots near the creek and on the steeper streets north of Cornell see the heaviest runoff, while the flatter blocks close to Murray Boulevard are more prone to a high water table and a wet basement even without a slope.

Because the terrain changes street by street, we do not offer one standard fix. Two houses a block apart may need very different work, and good waterproofing services in Cedar Mill start with measuring what each lot sends to the wall. The same crews cover Cedar Hills and Beaverton, which have similar clay soil and aging foundations.