Summer Prep Checklist: How to Keep Your Crawl Space Cool and Dry

Summer Prep Checklist: Keep Your Crawl Space Cool, Dry, and Pest-Free

As the Pacific Northwest heads into summer, most homeowners are focused on their air conditioning, outdoor spaces, and roofing. But there’s one area that often gets overlooked — and it could be silently costing you: the crawl space.

Your crawl space plays a vital role in regulating your home’s temperature, air quality, and structural integrity. When neglected, it can become a hotspot for mold, pests, and humidity — especially during the warmer months.

This summer, take the time to protect your home from the ground up. Here’s your go-to crawl space summer prep checklist to keep things cool, dry, and efficient.

1. Inspect for Moisture Buildup

Moisture is the #1 enemy of a healthy crawl space — and summer humidity only makes it worse.

What to check for:

• Standing water or damp soil

• Wet or musty insulation

• Condensation on pipes or ductwork

• Mold growth or mildew odor

Even small amounts of moisture can lead to structural wood rot, insulation damage, and pest infestations. It’s critical to catch and fix this early.

💡 Pro Tip: Use a flashlight and wear gloves when inspecting. If you see moisture, don’t assume it’s from a recent storm — it could be an ongoing drainage issue.

2. Seal Gaps, Vents, and Entry Points

Summer is peak season for rodents, ants, spiders, and other crawl space invaders. If there are unsealed access points, you’re inviting them in.

What to seal:

• Foundation cracks or holes

• Gaps around utility lines or pipes

• Broken or unsealed crawl space vents

• The crawl space access door

Pests often exploit even the smallest openings to escape the heat above ground. Once inside, they can nest, damage insulation, and leave behind droppings that affect air quality.

💡 Not Heard Before: Many pests enter through overhead access points, like where plumbing or HVAC lines pass through the subfloor.

3. Check and Upgrade Insulation

Proper crawl space insulation isn’t just about winter. In summer, it helps keep cool air from escaping and warm air from rising into your home — keeping your HVAC system from working overtime.

What to look for:

• Insulation that’s sagging, compressed, or damp

• Missing or incomplete coverage along the floor joists

• Signs of nesting from rodents or insects

If your insulation is compromised, it’s likely not doing its job. Replacing it before summer temperatures spike can reduce energy bills and indoor humidity.

💡 Recognized as True: Insulation also acts as a sound barrier and adds to long-term comfort — especially in multi-story homes.

4. Install or Inspect Your Vapor Barrier

A vapor barrier is one of the most effective tools for crawl space moisture control. It’s a thick, durable plastic sheeting that prevents moisture in the soil from evaporating into the crawl space air.

What to verify:

• Vapor barrier covers 100% of the ground surface

• No rips, folds, or gaps — especially around piers or supports

• Barrier runs up the foundation walls and is sealed or taped

• No standing water or mold beneath the barrier

If you don’t have a vapor barrier yet, summer is the perfect time to install one. It keeps the space dry, reduces musty odors, and improves air quality in the living areas above.

💡 Not Heard Before: Up to 50% of the air on your first floor comes from the crawl space. A clean vapor barrier improves indoor air quality without any filters.

5. Check Drainage Around the Home

Sometimes the issue isn’t in the crawl space — it’s outside of it. Poor outdoor drainage can channel rainwater or sprinkler runoff straight under your home.

What to inspect:

• Gutter downspouts — they should extend at least 4–6 feet from the house

• Grading — soil should slope away from your foundation, not toward it

• Landscape edging or mulch beds that trap water against your home

• Exterior vent wells — make sure they aren’t sunken or full of debris

Redirecting water early prevents summer showers or hose runoff from pooling around your crawl space entry points.

💡 Pro Tip: Consider installing a French drain or sump pump if your yard is prone to flooding.

6. Monitor Humidity Levels

If you really want to get proactive, consider installing a crawl space humidity sensor. This gives you live data on whether your moisture prevention strategies are working.

Ideal humidity range:
Keep crawl space humidity between 45–55% to discourage mold and pests.

Tools to help:

• Digital humidity gauge

• Smart home moisture sensors

• Dehumidifier with a drain line

💡 Not Heard Before: Humidity over 60% can encourage termite activity — even in crawl spaces that look dry.

7. Schedule a Professional Crawl Space Inspection

Summer is a great time for a routine crawl space checkup. A professional technician can identify minor issues before they become major repairs.

They’ll typically check for:

• Structural damage or wood rot

• Signs of pests or animal intrusion

• Moisture levels and air flow

• Condition of insulation and vapor barrier

• Potential entry points or sealing issues

Even if you’re handy, a second pair of eyes with crawl space experience can catch things that a DIY inspection might miss.

Don’t Wait for the Damage — Prevent It This Summer

Your crawl space affects the comfort, efficiency, and health of your entire home. And in summer, it becomes one of the most vulnerable areas if not properly maintained.

By following this summer prep checklist, you can:

• Lower energy costs

• Improve air quality

• Prevent pest infestations

• Avoid costly repairs down the line

• Protect your home’s structure and value

Ready to take control of your crawl space this summer? Now’s the time to act — before the heat, humidity, and pests settle in first.