Everything You’ve Ever Wanted to Know About Crawl Space Vapor Barriers

One of the realities of constructing and repairing commercial buildings is forever remaining aware of the dangers of moisture. Rotting wood, mold, chipped paint and more are all risks of water entering the building in areas where it’s not wanted. One good leak could cause tens of thousands of dollars of damage, and an area that is already susceptible could cause multiple rounds of damage if not dealt with effectively. So prevention is key to protecting buildings from the havoc moisture can wreak.

But a rotted roof and a massive storm aren’t the only ways moisture can enter a commercial building. It can also come from the ground up, causing damage building owners may not even think to look for until it’s too late.

Damage That Can Be Caused By Crawl Space Moisture

Most people don’t think twice about the space beneath a building. They might store tools, parts, and random odds and ends down there, but other than when they have to retrieve those items, the crawl space is often a forgotten area.

Unfortunately, crawl spaces typically have dirt floors, which makes them prime culprits for moisture entering the commercial building.  That’s because moisture infiltration in the form of water vapor from the soil, if not contained, can slowly erode your building from the ground up. We’re talking structural damage, electrical shorts, pipe erosion, and the degradation of insulation and fiberglass. Not to mention the risk of heavy allergens (like mold spores and dust mite droppings) entering your living spaces.

Luckily, a crawl space vapor barrier offers a relatively simple solution to all of this.

What is a Crawl Space Vapor Barrier?

Crawl space vapor barriers are durable membranes that work by preventing the infiltration of water vapor into the crawl space.   And when you combine a crawl space vapor barrier with a waterproofing system, now you have the ultimate moisture protection of the crawl space from both liquid water and water vapor before it has the chance to enter your building.

How do Vapor Barriers Work?

These barriers are typically thick plastic materials that are installed across the soil to prevent ground moisture from ever entering the space at all.

Now, it’s important to know these barriers only work to prevent ground moisture from migrating into your crawl space and building. Water runoff or leaking pipes could still result in moisture in the crawl space area, which is another reason to consider combining your barrier with a waterproofing system.

Is a Vapor Barrier Really Necessary For Your Crawl Space?

If you’re building in a drier climate, you might think you don’t have to worry much about crawl space vapor. After all, how much moisture could really be residing in the dirt beneath a building in Arizona, for instance?

The answer is a lot. In fact, an Advanced Energy study conducted in Flagstaff, Arizona found a 15 percent annual energy savings in homes and buildings where crawl spaces were sealed, indicating a drastic reduction in moisture, resulting in easier to control temps indoors.

No matter where you’re constructing, if a building has a crawl space, it can benefit from a crawl space barrier.

How Thick Does the Barrier Need to Be?

PERMINATOR underslab vapor barrier comes in 10 and 15 Mil thickness options. Deciding which thickness level is right for the building you’re working on often comes down to how much protection is needed.

And, for additional puncture resistance, PERMINATOR HP is also available and is furnished in a 15-mil thickness.

It is imperative that the barrier possess a high puncture resistance as it is going to be exposed, rather than protected by a concrete floor slab, and can be susceptible to damage.  The defining standard for plastic vapor retarders in contact with the ground is ASTM E1745 and both PERMINATOR 10 and 15 mil far exceed the requirements of this standard.

Where to Purchase Crawl Space Vapor Barriers

PERMINATOR underslab vapor barrier is available throughout Canada and the U.S., as well as in various locations worldwide. You can find a local distributor through our manufacturer website.

Before You Begin

Prior to installing a crawl space barrier, you’ll want to remove any items being stored down there so that you can have free access to the ground you’ll be covering. It’s also important to dry out the crawl space to the best of your ability before starting.

This can be accomplished by removing any visible moisture sources (such as puddles) removing wet insulation and debris, and potentially even calling in a professional to scrub surfaces clean of mold.

Once the crawlspace is clean and relatively dry, you’ll want to gather your tools for installation. These are the items you will find yourself thankful to have on hand:

• PERMINATOR
• PERMINATOR Tape
• TERMINATION BAR
• PERMINATOR BUTYL TAPE
• Lighting
• Shovel
• Pick axe
• Utility knife
• Replacement blades
• Hammer drill
• Reciprocating saw
• Tape measurer
• Screw driver set
• Hammer
• Wire staples
• Respirator
• Vacuum
• Towels

How to Install Crawl Space Vapor Barriers

Now that you’ve got the crawl space clean and dry, and you’ve gathered all your tools, it’s time to begin.

Installation of PERMINATOR underslab vapor barrier can be completed in a few simple steps:

1. Check local building codes for instructions on the gap you should leave unsealed from the top of the masonry wall, typically 3”. Apply PERMINATOR BUTYL TAPE around the foundation wall, where you’ll want the PERMINATOR underslab vapor barrier to attach.
2. To prevent tenting, and for a cleaner overall look, consider fastening PERMINATOR underslab vapor barrier to the base of the foundation wall by applying PERMINATOR BUTYL TAPE around the base as well.
3. Unroll the PERMINATOR underslab vapor barrier and spread it across the ground and up the foundation wall, sealing at the PERMINATOR BUTYL TAPE you’ve already applied.
4. Install the TERMINATION BAR over the top of the PERMINATOR underslab vapor barrier, in line with the PERMINATOR BUTYL TAPE.
5. Completely seal PERMINATOR underslab vapor barrier using PERMINATOR tape, to include all penetrations, all columns, and at the TERMINATION BAR.
6. Adjust PERMINATOR underslab vapor barrier across the crawl space floor to ensure complete coverage and enough barrier to rest flush against all surfaces.
7. Check local building codes for minimum overlap instructions. Some may call for at least six inches of overlap, while others may call for up to twelve inches of overlap. Overlap seams to at least the minimum requirements and seal with PERMINATOR tape.

Improving Crawl Space Cross Ventilation

As PERMINATOR is the industry-leading product for controlling vapor infiltration and also soil contaminants, such as radon, along with boasting a high puncture resistance, it is the perfect solution for crawl space moisture control. But you may want to consider combining it with additional water-proofing measures to maximize the reduction of moisture.

But what about water that may enter from runoff or leaking pipes?

Creating a waterproofing system in the crawl space area may best start with enclosing the area to prevent additional water entering from the outside. If the crawl space is completely enclosed, supplying air from the HVAC system can help to quickly evaporate any additional water that may enter the space. Installing a humidifier and exhausting air outside are also effective methods for keeping the crawlspace moisture free.

In the end, we all want to protect the commercial buildings we’re working on. And using PERMINATOR underslab vapor barrier to prevent ground moisture from entering a building through the crawl space is a great first step toward increased water damage protection.

Crawl Space Vapor Barrier Products & Accessories

 

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