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Top 5 Causes of Crawl Space Problems

Your crawl space could be the unlikely source of many different issues building up in your home. If you notice dingy smells, poor air quality, bouncy floors, and higher energy bills, the source could be coming from down in the crawl space.  

How do all of these problems start? Here, we’ll be discussing common causes of crawl space damage, and what you can do to stop it before it starts.  

The Root Causes of Crawl Space Problems

stack effect illustration

1. Stack Effect 

Hot air rises, and cold air sinks to the ground. This is the basic principle of the stack effect, mapped onto your home. Hot, humid air seeping into your crawl space will slowly rise into your living space and out through your chimney or roof. With this air comes all of the moisture, dirt, toxins, allergens, and even mold spores brewing in your unprotected crawl space.  

Since the stack effect is a completely natural phenomenon, there’s not much you can do to stop it aside from sealing, or encapsulating, your crawl space off from the external environment. This will prevent air of varying temperatures and moistures seeping in and setting the stack effect into motion.  

2. Poor Foundation Construction 

From the 1950s to the 1990s, installing doors during the construction of a crawl space was standard practice. Engineers and builders at the time believed that free airflow beneath the home would prevent trapping excess humidity below the home.  

This was proven to be false, as crawl space doors actually enable and accelerate the stack effect in your home. Additionally, crawl space vents will the same effect on your home; the damage will be even worse if they are broken, malfunctioning, or unsealed.  

flooding and drainage problems

3. Poor Drainage 

Poorly drained soil in your yard can also be the culprit for issues in your crawl space. Colorado is famously home to bentonite clay soil, which is known for its poor drainage capabilities. Pair poorly drained soil with negative yard grading, and you are sure to have water pooling around and infiltrating your foundation and crawl space. Any standing water or excess moisture in your crawl space is cause for larger issues down the line.  

4. Rotting Support Beams or Floor Joists 

If moisture and humidity do happen to plague your crawl space, the wooden structural support systems may suffer from mold growth or wood rot. As wood rot or mold form on your crawl space joists, they weaken the wood, causing it to soften and crumble. One way that inspectors test this is by gently puncturing the wood with a pencil. In extreme cases, a hole can be punched through the wood.  

This type of damage can be very alarming for the structural safety of your home. If your structural supports are rotting, you may notice sagging, bouncing floors in your living space. If this is the case, we recommend calling in the professionals as soon as you can.  

5. Weather

The western slope of Colorado is notably dry during the summer. Dry weather and clay soil aren’t a great mixture, as clay tends to shrink, shrivel, and crack. This can jeopardize your Grand Junction crawl space, as the soil below can no longer provide adequate support for your crawl space floor joists and foundation walls.  

How Can You Tell That You Have Crawl Space Issues? 

Since your crawl space is a dark and typically hidden place in the home’ it’s not the first place you’ll inspect for damage. However, your home will still find ways to tell you that the problem is coming from down under.  

Without addressing the above key crawl space agitators, you may begin to spot these below problem signs in your home.   

  • Musty Smells Around the House  
  • Bouncy, Sagging Floors 
  • Pests  
  • High Indoor Humidity  
  • High Energy Bills 
  • Standing Water  
  • Mold  
  • And more 

Do you notice any of these in your home? Explore below to learn more about crawl space problem signs.  

How Can You Fight Back? 

With the help of Foundation Repair of Western Colorado, encapsulation can be your crawl space’s first line of defense.  Crawl space encapsulation is the process of sealing up your crawl space from harmful outdoor elements like moisture, extreme temperatures, pests, and more. Service technicians encapsulate crawl spaces by covering all surfaces with a thick plastic-like vapor barrier, sealing the vents with foam, properly sealing the crawl space door, installing a dehumidifier, and sometimes more.  

Since there are so many reasons for crawl space damage, there are a variety of different solutions. Browse more of our permanent crawl space encapsulation solutions below to learn more.  

FAQs about Crawl Space Damage

The cost of crawl space waterproofing varies depending on the size of the crawl space and the extent of repairs required. For an accurate cost assessment, schedule a free inspection with Foundation Repair of Western Colorado. We provide detailed, no-obligation estimates and offer financing options to suit your needs. 

Yes, routine inspections are valuable for identifying mold and moisture issues before they escalate into widespread mold growth or other problems. After Foundation Repair of Western Colorado encapsulates your crawl space, you can benefit from our annual maintenance plans. We return yearly to assess your crawl space and ensure its ongoing safety. Contact us to learn more and schedule a free inspection

Yes. You can put a stop to the stack effect in your home and prevent it from impacting your property in the future. It’s all a matter of waterproofing, encapsulation, and proper and regular maintenance within your crawl space and property as a whole. The stack effect may be common, but it is not inevitable. 

Waterproofing and Encapsulation 

Crawl space encapsulation and waterproofing are the most reliable ways in which to prevent the stack effect (as well as a number of other issues) from damaging your home as a whole. Covering exposed vents is a large part of this process, but there is a lot more to it. As such, there are many different benefits to undertaking this process. Better still, this is not a hugely lengthy or invasive process; crawl space encapsulation can generally be undertaken in a day or less. 

The benefits of waterproofing and encapsulation go far beyond the prevention of the stack effect. Homes with fully encapsulated crawl spaces are less at risk of dampness, mold formation, and pest infestation. They also enjoy generally higher levels of heat and cold retention and will be more energy efficient as a result. Encapsulated crawl spaces can even be used for seasonal storage. 


Once waterproofing and encapsulation have been undertaken, maintaining the products and appliances that were used will be key to preventing a recurrence of the stack effect and its associated issues. A robust and regular maintenance schedule will ensure the benefits of your crawl space encapsulation process last. After all, while most insulation will last indefinitely, sump pumps have a life span of roughly eight to 12 years. 

As such, you should make seasonal inspections of your crawl space, drains, sump pump, and dehumidifier to look for signs of damage. Likewise, booking a maintenance appointment for your appliances on a seasonal basis will ensure that small issues are rectified quickly before they can snowball into larger ones. This will save you time, money, and stress in the long term. 

Michael Wilcher

Michael Wilcher

Michael Wilcher is the Content Lead at Groundworks, helping us to answer all of our customers biggest questions about foundation repair, basement waterproofing, crawl space encapsulation, and concrete lifting. In his free time, Michael enjoys collecting vinyl records, watching Formula 1 Racing, and reading philosophy. He holds an MPhil from the University of Cambridge.

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