With rising summer temperatures comes rising humidity levels, which can mean trouble for crawls spaces, basements and foundations. Though high humidity may seem harmless, it can cause slow, but serious, damage to crawl spaces, foundations, and basements. Let’s take a look at the damage of summer humidity, signs to look for, and what you can do about it.

The Silent Damage of Summer Humidity: How It Affects Crawl Spaces and Foundations

First of all, why is there so much more humidity in the summertime than the winter? Warmer air can “hold” more moisture than colder air. This means the highest potential for the highest levels of humidity will occur during the hottest days, which usually happen in the summertime. The summer also tends to get more rainfall, which can quickly raise humidity levels.

A lot of this moisture ends up seeping into the soil, which often ends up accumulating around the foundation of our homes. This is especially true if the ground around the home slopes towards the foundation, instead of sloping away from it. All of these factors combined means moisture sits in or near the foundation, basement, or crawl space, which means much higher humidity. But what does this mean? Let’s take a look.

Don’t let summer moisture endanger your home
Get an expert assessment and fix moisture problems >

1. Moisture Buildup in Crawl Spaces and Basements

During humid months, warm air finds its way into the cooler, shaded crawl space or basement beneath your home. When that moist air meets cool surfaces like pipes, ducts, or foundation walls it condenses into water droplets. Over time, this constant cycle of condensation leads to damp conditions that promote mold, attract pests, and weaken structural materials.

2. Mold and Mildew Growth

A warm, damp crawl space is a perfect environment for mold and mildew. Once mold takes hold, it can spread quickly across wooden beams, insulation, and even HVAC components. Beyond the damage it does to materials, mold also creates musty odors and can cause cold-like symptoms, especially if it gets into your air circulation system.

3. Wood Rot

Prolonged exposure to moisture doesn’t just affect your crawl space or basement, it can even damage your home’s structure. Wooden joists, beams, and subfloors begin to absorb the excess moisture, leading to wood rot over time. This structural weakening can eventually cause uneven floors, sagging ceilings, and costly repairs.

4. Foundation Wall Cracks

When humid air increases soil moisture, the ground around your foundation may expand or become overly soft. This puts added pressure on foundation walls, often resulting in cracks that allow even more moisture inside. Foundation cracks are not just cosmetic, either; they can compromise the stability of your entire home.

5. Pest Problems

Humidity draws pests like termites, carpenter ants, cockroaches, and rodents into your crawl space and basement in search of water and shelter. Once inside, they can chew through insulation, wood, and wiring, creating further damage and health risks.

6. Musty Odors

One of the earliest warning signs of basement or crawl space humidity is a musty odor that slowly makes its way into the rest of the home. These smells are usually caused by mold, mildew, or decaying organic material and can become persistent and difficult to remove if the root cause—moisture—isn’t addressed.

7. Higher Indoor Humidity and Energy Costs

Moisture from the crawl space or basement doesn’t always stay below ground. It can rise into your home, making the indoor air feel heavier and warmer. That extra humidity forces your air conditioner to work harder and longer, which leads to higher energy bills. You won’t see it happening, but a humid crawl space can quietly drain your wallet all summer long.

8. Rust and Corrosion

Crawl spaces and basements often contain exposed metal components like plumbing pipes, fasteners, and HVAC ducts. Humid air accelerates rust and corrosion, which can shorten the lifespan of these systems and lead to costly replacements.

9. Sinking or Settling Foundations

When humidity alters the moisture levels in the surrounding soil, it can cause the foundation to shift. Overly moist soil may become unstable, leading to uneven settling or cracks in the structure above. This is especially common in homes built on clay soils or in regions with fluctuating humidity and rainfall levels.

10. Efflorescence on Foundation Walls

If you notice white, powdery residue on your foundation walls, that’s called efflorescence. It’s caused by water moving through concrete or masonry and bringing salt minerals to the surface. While efflorescence itself isn’t harmful, it’s a clear sign that moisture is entering your foundation and it should be addressed quickly.

Stop Humidity From Damaging Your Crawl Space or Foundation

Summer humidity may be invisible, but its impact on crawl spaces and foundations is very real. If you’ve noticed musty smells, sagging floors, or increased energy bills, now is a good time to act. A professional inspection can identify hidden moisture issues before they turn into major repairs. Give us a call at 1-800-782-9379 or schedule an appointment online today to get a free consultation. We’ll tell you about your basement waterproofing and crawlspace encapsulation options, so you can move forward with confidence.