What Most Contractors Miss During Crawl Space Assessments

What Most Contractors Miss During Crawl Space Assessments

When it comes to protecting the foundation of your home, few things are more important than a crawl space evaluation.

Unfortunately, though, not all assessments are created equal. Most contractors aim to only collect basic information to produce a proposal in accordance with Plan Set A. Essentially, they are just doing a cursory check to determine if you have any cripple walls or not. There are a few nuanced issues that often go unnoticed.

Though these may seem minor, over time, they can become a huge issue. Therefore, we decided to educate you on the most common things contractors miss during a crawl space assessment.

1.  Excessive Humidity

Sometimes, contractors will visually look for humidity. However, this isn’t enough in these small, dark spaces. Ideally, they need to be using a hygrometer.

A hydrometer is a tool that measures water vapor in the air. It’s, without question, one of the most effective and accurate ways to test crawl space humidity.

Testing for humidity is essential. If you have excessive relative humidity in a crawl space (over 60%), mold can grow. When mold starts growing, it can damage the property’s structural integrity and reduce the quality of air in a property.

2.  Missing or Damaged Vapor Barrier

A vapor barrier, which is a sealed polyethylene barrier on the crawl space’s floor, keeps ground moisture out of the space.

When it is missing or damaged, excessive moisture can enter the space, raising humidity, increasing the chances of mold, etc.

Missing vapor barriers are somewhat simple to detect. On the other hand, a damaged vapor barrier is a little more difficult. More often than not, small cracks, rips, or poorly sealed barriers can go unnoticed.

In fact, there has been research suggesting that as much as 15 gallons a day of water vapor can enter a crawl space via an improperly sealed vapor barrier.

3.  Hidden Mold Growth

Mold can grow anywhere. Sometimes it’s in obvious places and other times not. It’s the other times, however, that are often missed.

With a crawl space assessment, it can be difficult to see mold on the underside of floors, wood joists, and behind insulation. These areas aren’t within direct view.

Although you can’t see it easily, it can still present the same mold issues. It can spread into wood, reduce air quality, and send spores into the property.

4.  Early Pest Signs

Alongside the above, sometimes the early signs of pests can be overlooked.

Without question, when a property has a full infestation, it’s very obvious. You can physically see, and sometimes hear and smell them.

Early signs, however, are a little more difficult. It requires a more thorough look. Yet, despite this, if you spot this issue early, the solution is much more cost-effective, and future problems are mitigated.

Pests are common in the U.S. as well. More common than a lot of people think. The U.S. Census Bureau states that about 14.8 million homes in the U.S. had rodents within the last year. That’s what makes looking for subtle pest signs (droppings, etc.) so important.

5.  Wet or Fallen Insulation

Often, insulation under a crawl space’s floor doesn’t get evaluated. However, if it’s wet or sagging, it can lose much of its insulation power. Not only this, but it can even attract mold and vermin.

6.  Dripping Pipes or “Sweating” Lines

If not carefully examined during a crawl space evaluation, dripping pipes or sweating lines can also go unnoticed.

Generally, dripping pipes can be caused by small leaks from plumbing or HVAC lines. Sweating lines can be from condensation forming on chilled pipes, which then drips onto the ground.

Though these small water droplets may seem harmless, they can quickly push humidity levels upwards. This, in turn, can trigger mold growth or cause structural damage.

7.  Unstable Support Posts or Shims

These are pretty easy to spot. It just depends on what type of contractor you hire.

Most “free estimate” retrofit contractors offer “quick” fixes—for example, stacked concrete blocks, wood shims, screw-jacks, etc.

At first, these fixes may seem to hold up fine, but they should only be temporary. They’re not code-compliant as permanent supports and can shift or fail over time.

8.  Leaky or Disconnected Ducts 

All your HVAC ducts should be well-sealed and insulated. This can be difficult to spot sometimes in a quick crawl space visit.

Whatever you can see with your eyes is simple. A proper check, however, around the back of the ducts may be missed. This, though, is usually the area where leaks, disconnected, or poorly insulated ducts can’t be spotted.

As you can imagine, this means a less effective HVAC system. In fact, Energy Star suggests that 20 to 30 percent of air from a HVAC system is lost through leaks, holes, and poorly connected ducts.

Complete Crawl Space Evaluation Checklist

Item	Yes	No
Organics, vegetation, forms, and construction materials removed
Vapor barrier
Anchor bolt spacing and size meet code requirements
Floor joist size and installation comply with code
Plumbing, HVAC, or electrical work did not compromise floor joists
Correct pier spacing, size, & condition
Seismic connections for continuous load path
Beam constructed properly
Floor joists blocked
Cripple wall (if any) properly framed and sheathed
Beam and floor maintain proper distance from grade
Floor insulation installed with correct R-value and vapor barrier on warm side
Ventilation space size and location comply with code
Access panel size and height meet code requirements
Utility connections and insulation comply with code
Crawl space is free of standing water or stains
Humidity levels measured (target RH ≤ 60%)
No visible mold or mildew on joists, insulation, or subfloor
Vapor barrier (if any) sealed at seams and edges
No signs of pest activity (droppings, nests, gnaw marks, termite tubes)
Plumbing lines dry & free of drips, corrosion, & condensation
HVAC ductwork sealed, insulated, and securely connected
No exposed electrical wires or open junction boxes
Crawl space entrance is unobstructed and safe to access
Crawl space lighting (if present) is functional and safe

Please note: This is a sample crawl space evaluation checklist. Your home may have fewer or more items for assessment. For example, your home may not have any ducts or piers in the crawl space.

How to Find a Professional for a Crawl Space Assessment

A key factor to getting a proper crawl space evaluation is finding the right professional—someone who is licensed, certified, and reputable.

You cannot expect a thorough assessment from “free estimate” contractors.

Step 1: Verify Licensing and Certification

If you’re based in California (like we are), you’re able to look up contractors on the California Contractors State License Board (CSLB) website. The contractor you choose should hold a general building or specialized license.

Step 2: Use Reputable Directories

Once you’ve found a selection of licensed contractoirs, seek reviews from them. To find reliable reviews, we recommend that you check out the Better Business Bureau, HomeAdvisor, Angi (Angie’s List), or Google Reviews.

Step 3: Ask About Experience

After completing the two steps above, you should have a few licensed, certified, and reputable contractors.

You now want to contact them and ask about their experience. Ideally, you want to find out if they understand crawl space moisture control, the difference between types of plans (Plan Set A, FEMA P-1100-2A, etc.), and new construction building codes (for example, in the Bay Area, more stringent seismic codes).

Step 4: Check Insurance and Warranty

While speaking to the contractor, it’s always a good idea to request proof of insurance and if they offer warranties for their work (for warranties, a formal, written document is best). This will ensure that you’re protected for any work that commences.

Step 5: Compare Quotes and Proposals

Lastly, get a few different quotes. Rather than only looking at price, you will want to look for the most thorough, detailed, and complete options.

Contact Us Today

At Avant-Garde, we believe that your crawl space should never be overlooked. It’s the foundation of your home’s health and integrity.

That’s why our team is professionally trained for crawl space assessment. We’ll happily detect any issues (minor or major) in your crawl space and suggest the best solutions.

For more information about how we can help, contact us today. Waiting will be a helpful representative eager to schedule a visit.