Gig Harbor is a hotspot for foundation problems for several reasons, each contributing to the potential for property damage and costly repairs. We’ll discuss the sources of these issues below, along with an explanation of how each affects your foundation.
Probably the most significant threat to your home’s foundation is the soil in Gig Harbor.
Much of the ground in Washington state has a high accumulation of clay particles and a relatively small concentration of silt and sand particles. The result is clayey soil that is referred to as expansive. Expansive soil is detrimental to concrete foundations for three primary reasons.
The first is that it swells when it gets wet. Clay particles are tiny and compacted, so they absorb water readily and in more significant volumes. When rain falls in Gig Harbor, the clay-rich soil soaks in water and expands, placing intense pressure on your foundation. The added stress frequently creates inward movement of concrete block walls or upward heaving of concrete slabs, ultimately resulting in the loss of your foundation’s structural integrity.
The exact opposite is true of expansive soil as well: it shrinks when it dries. During stretches of minimal rainfall, the water held by the clay soil can drain into the earth or evaporate out of the ground, allowing the dirt to lose the volume it gained as it took in moisture. Settling of the earth under and around your foundation can happen at varying rates, leading to differential settling.
Uneven settlement of the earth under your foundation can leave areas of your home unsupported. Unable to withstand the weight of your structure without the help of the ground below, your foundation cracks and sinks until it reaches the supportive earth again.
This process very quickly causes structural damage and can be extremely costly to repair.
Lastly, clay-rich soil retains water more easily and for longer times than typical dirt.
Therefore, the ground in Gig Harbor holds moisture against your foundation for days or weeks following precipitation, allowing it to wick in through cracks or pores in the concrete. As such, the homes built on expansive soil are at higher risk of water damage and hazardous moisture accumulation.
Above-Average and Frequent Rainfall
The problems created by expansive soil are made significantly more impactful because of the frequent rainstorms in Gig Harbor. The city experiences more than 48 inches of rain annually, which is about 50% higher than the national average. Most months throughout the year bring measurable precipitation nearly every other day, on average.
The above-average and frequent rainfall mean that the soil remains heavily saturated for long periods, maximizing the pressure on your foundation from the swelling ground and leaving your concrete continuously exposed to moisture.
It also increases the chance of flooding in Gig Harbor and other cities on or near the bay or rivers, including Marysville, Port Orchard, Redmond, Snohomish, Renton, and Steilacoom.
June through September in Gig Harbor generally brings significantly less rain, averaging about half of the monthly rainfall the rest of the year. The ground during this time tends to dry much more, causing the soil to shrink. The regular cycle of swelling and shrinking means frequent ground movement that can create structural problems in your home.
The heavy rain and poor soil drainage in Washington make landslides a prevalent issue throughout the state. Although they’re less frequent in Gig Harbor due to the gentle slopes, they can still affect your foundation’s integrity. The movement of heavy soil and runoff can cause isolated damage to your home and put added pressure on your concrete block walls.
The Tacoma fault zone and the Cascadia subduction zone are both located very near to Gig Harbor. The regular and sometimes intense ground movement during shifting leaves the area at moderate-to-high risk of earthquake damage. Even small earthquakes can shift the ground enough to create weaknesses in your foundation.
Frequent shaking can contribute to differential settling and inward pressure on your foundation walls, making the risk of structural damage more severe.
Lastly, the humidity in Gig Harbor is an issue for many homes in the area. The average relative humidity throughout the year tends to fluctuate between 65% and 85%. Humid air outside your home eventually makes its way into your crawlspace or basement, where the moisture naturally gets trapped.
Elevated moisture levels under your home contribute to various issues, including water damage, pest infestation, mold growth, and the gradual destruction of building materials.