Kirkland’s hillside homes and waterfront properties often experience increased groundwater pressure and slope runoff. We provide reliable waterproofing and mold services built for Kirkland’s terrain.
1. Geology and Soil Conditions
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Much of Kirkland’s surficial geology is comprised of Vashon Till (Qvt) and underlying glacial outwash deposits. A geotechnical report for a site in Kirkland states: “The subject site is underlain by Vashon till (Qvt) with Vashon advance outwash (Qva) mapped about one block to the east.” Kirkland Permits+2UW Libraries+2
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Vashon till typically is a very dense, poorly sorted mixture of silt, sand, gravel, cobbles and boulders deposited by glaciers; it has low permeability. Kirkland Permits
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Additional mapping shows in the upland plateaus of Kirkland a blanket of till over outwash, and in some exposures even stiff to hard clay deposits (e.g., “Vashon Lawton Clay”) underlying. UW Libraries
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Because of this dense till / layered fine‑grain structure, water that infiltrates the soil may not drain freely downward; instead, it can become perched or move laterally (toward basement walls). For example: “wet sediments were observed at … 10 ft below the surface in the till and advance outwash near the contact” in a Kirkland subsurface exploration. Kirkland
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Implication: On many Kirkland lots, basement walls are adjacent to soils that are slow‑draining, meaning hydrostatic pressure builds more easily and water may accumulate behind walls or under slabs.
2. Rainfall and Seasonal Moisture Load
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Kirkland has a high number of rainy days and a notably wet season. One climate summary: “In Kirkland, during the entire year, the rain falls for 175.1 days and collects up to 28.58 inches (726 mm) of precipitation.” Weather U.S.+1
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Monthly rainfall shows December at ~4.21″ in Kirkland. Weather U.S.
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The “wet season” runs roughly from October through early May, with many wet days; for example November has ~17 rain days. Weather Spark
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Implication: The combination of frequent rainfall and soils that do not drain easily means soil moisture around basement walls can stay elevated for prolonged periods, increasing the risk of seepage or water intrusion.
3. Topography and Drainage Characteristics
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Kirkland’s terrain includes upland plateaus, glacially‑carved ridges/valleys, and lowland/shoreline areas near Lake Washington. From geologic work: “The annexation area consists of two broad upland plateaus divided by glacially derived channels.” UW Libraries+1
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On sloped lots, or where surface water or subsurface water flows toward a structure, drainage can become compromised. The city’s stormwater / drainage guidance emphasizes managing surface water runoff and identifying impervious surfaces. Kirkland
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Implication: Homes built on or near slopes, or with inadequate outward grade, face elevated risk that runoff or perched subsurface water will accumulate at or near the foundation — especially when underlying soils are slow‑draining.
4. Combined Effect: Why Basement Water Risk is Elevated in Kirkland
Bringing it all together:
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The foundation of many homes in Kirkland sits adjacent to soils with dense glacial till / outwash / sometimes clay layers that impede drainage.
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Frequent rainfall and many wet days keep soils near capacity, allowing water to build rather than drain away.
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Terrain/slopes and development patterns may direct surface or subsurface flow toward foundations or basement walls.
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As a result: increased hydrostatic pressure on foundation walls, potential lateral water migration, longer periods of wet soil adjacent to basements — all contributing to elevated risk of basement seepage, dampness or flooding.
Kirkland basements often experience seepage through foundation walls and floors. We install:
- Interior French drains
- Vertical drain wall membrane
- Sump pumps and battery backups
- Exterior drainage solutions
Seattle homes typically deal with:
- Water seepage during heavy rain
- Standing water from seepage in cold joints
- Damp walls and floors
- Musty odors
- Mold growth on wooden framing
✔ Local Kirkland basement waterproofing specialists
✔ Permanent solutions and warranties
✔ Certified mold remediation team
✔ Custom solutions for hillside homes
Serving all neighborhoods in Kirkland, WA
Request a free waterproofing estimate today.