Water in Your Crawlspace: The Cohesion Effect

A small puddle in your crawlspace might not seem like a big deal. It’s easy to dismiss it as a minor nuisance; just a bit of condensation that will eventually evaporate. But what if that tiny amount of moisture had a secret superpower, allowing it to attach to itself, attract more of itself, spread, climb, and silently compromise the very structural integrity of your home?

This superpower is a fundamental property of water called cohesion, and when it teams up with adhesion and capillary action, it becomes a triple threat. Now, a minor moisture problem can quickly escalate, potentially leading to mold and fungal growth, wood rot, termites, and other costly damage. This is the secret superpower of water.

The Magic of Cohesion and Capillary Action

At its simplest, cohesion is the tendency of water molecules to stick to each other. This is due to hydrogen bonding, which creates a kind of “skin” on the surface of water, allowing many insects to walk on it and causing water to bead up. But in the confined spaces of your home’s building materials, cohesion becomes a destructive force that has one remedy: complete elimination. The power of water can cause a small, simple leak to draw additional moisture through cohesion, turning a lightly damp crawlspace into a disaster.

If that wasn’t enough, when cohesion combines with adhesion (water’s ability to stick to other surfaces), it creates capillary action. This is the process where liquid spontaneously moves upward through narrow tubes or porous materials, defying gravity.

Think of it like a paper towel soaking up a spill. The water is pulled into the tiny spaces between the paper fibers. The same principle applies to the wood and concrete in your crawlspace.

• In Wood: As research from the USDA Forest Service and others confirms, wood acts as a complex capillary system. Water molecules are attracted to the cellulose fibers in wood grain through adhesion. Once adhesion begins, cohesion doesn’t stop. Instead, adhesion and cohesion work in unison to bring more water to the surface. As more water adheres to the surface, that surface water may cohere to incoming water, exacerbating the problem. Given the right amount of adhesion to the wood surface and the cohesion of incoming water, capillary action can begin. As this occurs, water is pushed upward through the wood fibers. As long as cohesion is present below (incoming water joining water adhered to the surface), capillary action can move that water from the crawlspace into the walls and other building materials. This means a small but persistent leak can have devastating repercussions. This process is even more effective when wood-to-ground contact is present.
• In Concrete: Foundation walls and footings are porous. Groundwater can be drawn up through these tiny pores via capillary action. As this process occurs, adhesion can transfer water already adhered to the concrete or block onto the wood in contact with it. Now, as the processes of cohesion, adhesion, and capillary action take place, damage can occur.  One source noted that porous building materials can theoretically wick water for distances of up to several miles, if they were stretched out that distance! This may be extreme, but this, again, is the superpower of water!

From a Damp Spot to a Major Problem

This is how a seemingly small issue becomes a larger one. That minor puddle or damp area, maybe from a small plumbing leak or minor condensation, isn’t just sitting there. It’s being actively pulled into the building materials. As those building materials absorb moisture, more moisture is attracted to them. As this process repeats, your crawlspace can get really wet and sustain serious damage.

1. The Wick Effect: A damp spot on a wooden floor joist isn’t just wet on the surface. Through capillary action, water travels along the wood grain, spreading the moisture far beyond the original point of contact. This dramatically increases the surface area of wood that is being exposed to damaging moisture.
2. Feeding Mold and Rot: Crawlspace moisture is a primary cause of mold growth and wood rot. By spreading moisture through the wood, capillary action creates the perfect, widespread environment for these destructive organisms to thrive. What could have been a localized water leak repair becomes a widespread moisture problem and a potential mold or other wood-destroying organism infestation, weakening critical structural components.
3. Elevating Humidity: Water that migrates into materials doesn’t always stay there. It evaporates into the air, significantly raising the humidity level in the enclosed crawlspace. This humid air then rises into your living spaces (a phenomenon known as the “stack effect“), carrying mold spores and a musty odor, and potentially affecting indoor air quality and comfort. This means your crawl space could negatively affect your health.

Don’t Underestimate a Little Moisture

The property of cohesion, expressed through capillary action, means that water in your crawlspace is rarely passive. It is an active invader, seeking out pathways to spread and cause damage. A small, persistent damp spot is not a minor issue; it is a symptom of a process that can lead to severe structural damage, mold contamination, and pest infestations.

Ignoring it because it “doesn’t look that bad” is a gamble with your home’s health and stability, and potentially with your and your family’s health! Addressing moisture at its source through solutions such as proper drainage, vapor barriers, crawlspace encapsulation, and dehumidification is crucial to stopping this powerful natural force in its tracks.

How Four Seasons Pest Solutions Can Help

Our team of experts understands how damaging water can be to a home. That’s why we offer crawlspace and basement solutions designed to keep water out. Our services include rerouting water runoff, managing gutter downspouts, and adjusting other water discharge lines. We also focus on eliminating humidity, groundwater, and hydrostatic pressure against foundation walls.

Whether it involves adding new drains, installing a crawlspace encapsulation, or simply adding a dehumidifier, we handle it all. Even if mold and fungus are already present, we can remediate the infestation, stop the water, and create a safe and healthy environment in your crawlspace. We can’t stop cohesion, but we can prevent it from occurring in your crawlspace!