The Crawl Space: Is it a Storage Option?
We finally settled on a three-bedroom home with the requisite bonus room and a sizeable crawl space. The home was built on a hill, which allowed the crawl space to be 7 feet or higher in some places. My initial thought was that the builder should have spent the extra money to frame a walkout basement. But as with everything, you have to draw the line somewhere, and I’m sure that is what happened with the original owners of the home. But I reasoned that given this amount of space it would make for a great storage area.
Key Takeaways
- The Hidden Danger of Moisture: Standard crawl spaces are notorious for trapped moisture and poor ventilation. Even if the ground looks dry, condensation can lead to rapid mold growth on joists and stored items.
- Irreplaceable Loss: Household items like photos, memorabilia, and holiday decorations are highly susceptible to mildew. Once the smell of mold permeates these items, they often have to be thrown away.
- Health Implications: A moldy crawl space doesn’t just affect your belongings; because of the “stack effect,” much of the air you breathe inside your home originates in the crawl space, potentially triggering allergies and respiratory issues.
- The High Cost of Retrofitting: Turning a crawl space into a viable storage area (encapsulation) requires professional sealing, sump pumps, and commercial dehumidifiers, which can cost anywhere from $7,000 to $14,000.
- Concrete Isn’t a Quick Fix: Pouring a concrete slab in a crawl space without a proper thermal break can actually worsen condensation and mold issues.
- Storage Units as a Cost-Effective Alternative: For most homeowners, renting a climate-controlled storage unit is a far more affordable and immediate way to protect sensitive items compared to the massive upfront investment of home encapsulation.
- Climate Control is Key: If you do use a crawl space, it must be “humidistatically-controlled” (maintaining roughly 40% humidity) to safely house electronics, artwork, or paper records.
So, I made the decision to make this our priority storage spot for the house. The builders had put down a few pieces of plywood that allowed for a small platform in front of the door to the space, but this needed major expansion if I was going to be able to fit all our family’s stuff down there. I calculated that a 12’ x 20’ platform would do the trick. My father-in-law and I put in several joists, which we anchored into the concrete foundation wall. On top of this, we laid down plywood to create the 12’ x 20’ storage area. Once finished, I put in a number of shelving units and brought down all of our extra storage items—holiday decorations, lawn furniture, sporting equipment, family memorabilia, etc.
I wish this were the end of the story. But sadly, it’s not.
The rest of the winter was uneventful. In fact, the next couple of years were uneventful regarding the crawl space. Or so I thought.
Destroyed Memories
This was devastating news. I immediately took everything out of the crawl space. For some items like the lawn furniture, I was able to wash them and lay them out in the sun to air out. For other items like our holiday decorations and memorabilia, I took them out and thoroughly washed the containers I had stored them in. Some of the items ended up in the garbage as the smell of mold never left. The remaining items I placed in a small storage unit I rented at West Coast Self-Storage.
Concrete or Plastic
My other option was to install an impermeable crawl space vapor barrier in a process called “encapsulation.” These barriers, also known as crawl space liners or membranes, are typically made of reinforced polyethylene and can range in thickness from 6 mil (the minimum needed to stop moisture), all the way up to 90 mil with 12-20 mil being most commonly used in crawl spaces. (1 mil is equal to 1/1000 of an inch.) The barriers create a perfect seal to the crawlspace, thereby completely blocking moisture and creating a humidistatically-controlled environment (almost like a climate-controlled storage unit!).
Both of these options are expensive. Concrete slabs for my size of house would have run anywhere from $7,000 to $9,000. And the quotes I got for the vapor barrier ranged from a high of $14,000 to a low of $9,000. In the end, I opted for the vapor barrier for the reasons mentioned above.
After getting a few bids, I hired a company called Dr. Crawlspace to do the work. Greg, the owner, and his crew first sealed up the vents to the crawl space and tore out the old fiberglass insulation in the rafters.
They installed a sump pump to carry away excess water and installed a commercial dehumidifier. Then they laid down a hard plastic dimple underlayment, which provided structure and stability to allow us to walk on it. It also acted as another layer of vapor protection.
Next, they installed the vapor barrier itself, which ended up being a white, 16 mil, fire-retardant material called CrawlShield. They glued the fabric to the concrete walls and interior piers, making sure there were no places for leaks. Lastly, they sprayed foam insulation in between the wall studs around the whole crawl space to better insulate it.
A Usable Space
Given this new, well-regulated environment, I’m able to store more sensitive items like electronics, artwork, and even archived business records that I want to keep in great condition over the coming years, but this wasn’t done without overcoming a massive and rather expensive hurdle.
While I decided to keep the storage unit for certain items, I’ve been able to put most things back into the crawl space without having to worry about whether they’ll be destroyed by moisture or mold. And my family is breathing mold-free air.
