Licensed & Insured. Crawl space Encapsulation and Mold Remediation

The Right Mil Plastic for Vapor Barrier Explained

Have you ever experienced the dankness of a cellar or below-ground space? That clammy feeling is often due to moisture seeping up from the ground. But an unsung hero battles this creeping wetness: the plastic for vapor barrier.

This unassuming crawl space vapor barrier material may not look like much, but it’s one of your home’s best defenses against water damage and mold growth. When used correctly, it can keep spaces dry and comfortable.

You might think, “Well, all vapor barrier plastic sheets are alike.” Not quite! There are many types with varying thickness (or mil). 

Picking the right one can feel daunting without guidance. So, ready to learn all about the mil thickness of plastic for vapor barrier? We’re talking benefits, pitfalls to dodge, and price points. 

Keep reading – there’s lots more ahead!

Table Of Contents:

What Mil Plastic is for Vapor Barrier?

The mil (thickness) of plastic, or polyethylene sheeting, has become a staple in crawlspace encapsulation. But what exactly is it? In plain language, “mil” denotes the girth of the plastic sheeting – not millimeters, but one-thousandths of an inch.

A higher mil count means a thicker and more durable barrier. The most common types used are 6 mil (economy grade) up to 20 mil (contractor grade). These barriers prevents moisture from creeping into your home from the damp soil below.

The Role of Mil Plastic in Crawlspace Encapsulation

Crawlspace encapsulation involves sealing off this underground area with a vapor barrier like polyethylene plastic sheeting. This technique removes excess humidity, protecting your property from mold growth and structural damage caused by rotting wood.

Besides its protective role against moisture-related issues, installing a vapor barrier or vapor retarder can also help regulate temperature within your home and potentially reduce energy costs over time.

Types of Mil Plastic for Vapor Barrier

In conclusion, choosing the right type of mil (thickness) for your vapor barrier project is not just about cost or convenience. It’s also about picking a product that matches the specific needs of your crawl space—be it regular moisture control or more specialized applications such as radon mitigation.

When planning a crawlspace makeover, choosing the right type of mil plastic for your vapor barrier is crucial. But picking one can feel like a Herculean task with several types available.

The first contender in our lineup is 6-mil polyethylene sheeting. This lightweight option may seem like an economical choice, but beware. Its thinness makes it prone to rips and tears during installation or routine maintenance checks.

8-mil reinforced polyethylene (RPE), on the other hand, brings more toughness to the table. Reinforced with a layer of polyester scrim sandwiched between two layers of low-density polyethylene (LDPE), this variant offers higher durability than its 6-mil counterpart.

Premium Options: 12-Mil and 20-Mil Crawl Space Liners

If you want premium protection from moisture invasion, consider thicker options such as 12-mil crawl space liners or even robust 20-mil variants.

These barriers resist punctures while offering superior water vapor resistance—ideal when dealing with damp crawlspaces.

A Special Mention: Zero Perm Vapor Barriers

In scenarios where complete sealing off from ground vapors is needed—for instance, radon gas mitigation—you might need something more potent than traditional mil plastics; enter zero perm vapor barriers.

The EPA recommends these high-performance barriers, which block virtually all soil gases. They are constructed with unique materials like aluminum and are great for creating healthier indoor environments.

Types of Mil Plastic for Vapor Barrier

Key Takeaway: 

Choosing the suitable mil of plastic for your vapor barrier is vital. Options range from lightweight 6-mil polyethylene prone to tears and more durable 8-mil RPE to premium robust liners like 12 and 20-mil variants that resist punctures and offer superior moisture resistance. For specialized needs such as radon mitigation, consider zero perm barriers.

Picking the Right Thickness for Your Project

Choosing between different mil (thickness) may seem daunting at first. While budget might steer you towards thinner options like 6-10mil sheets, they’re less resilient than their sturdier counterparts, such as 12-20mil ones.

If longevity matters to you more than initial cost savings – go thick. A strong vapor barrier will stand up better under pressure…literally. 

It can resist punctures due to frequent foot traffic during installation or subsequent maintenance visits.

Mil of Plastic and Your Health

Did you know that damp crawlspaces can negatively impact your indoor air quality? A well-installed vapor barrier helps prevent mold spores and other allergens, contributing to a healthier living environment.

The key here is “well-installed”. Proper installation is crucial to maximize the benefits of plastic for vapor barriers. This includes ensuring full coverage with overlaps sealed using appropriate tape like butyl tape or sealant.


Key Takeaway: 

A higher mil of plastic or a thick polyethylene sheeting is vital in crawlspace encapsulation to guard against moisture and regulate home temperature. While higher mil counts offer more durability, it’s essential to balance your budget and longevity needs. A well-installed vapor barrier also promotes healthier indoor air by preventing mold growth.

Benefits of Using Higher Mil Plastic Sheeting for Vapor Barrier

If you’re in the market to give your crawlspace a makeover, the mil of plastic for vapor barrier should be on your list. But why is that so? 

Benefits of Using Higher Mil Plastic Sheeting for vapor barrier

Durability That Stands The Test Of Time

The higher mil plastic for vapor barrier or vapor retarder has robustness built into its core. It’s tough and resistant to punctures or tears – which means it can stand up against rough conditions underneath your home without needing frequent replacements.

An Ally Against Moisture

This wonder material isn’t just strong; it acts as a moisture barrier. Higher mil polyethylene plastic sheeting creates an impenetrable shield between your crawl space and the earth below. 

This keeps humidity out and prevents issues caused by excess moisture, such as mold growth or structural damage.

The Cost Advantage

We all love saving money where we can, right? Here comes another plus point – using heavy duty poly sheeting helps cut down costs, too. 

Keeping crawl spaces dry saves you big bucks on potential repair expenses due to water-related damages over time. HomeAdvisor estimates those fixes could run into thousands.

A Friend To Your Energy Bills

Besides helping keep repairmen at bay, this superhero doesn’t stop there. 

Did I mention how appropriate mil of plastics for vapor barrier contribute towards energy efficiency too? Yep. 

Maintaining a dry crawl space reduces the load on your heating and cooling systems, leading to lower energy consumption and friendlier utility bills.

From my hands-on work with vapor barriers in homes and businesses, the suitable vapor barrier thickness for polyethylene plastic sheeting has shown its value again and again. It’s tough against daily wear, guards well against moisture issues, saves on upkeep costs, and even help reduce energy use.


Key Takeaway: 

Don’t overlook the mil (thickness) of plastic for vapor barriers when revamping your crawlspace. This tough stuff stands up to harsh conditions so that you won’t need replacements often. But it’s not just strong – it also fights off moisture, shielding your home from mold and structural harm.

Installation Tips for Plastic Sheeting for Vapor Barrier

Laying down the plastic for a vapor barrier is no small feat. But with the proper steps, it’s a job you can tackle head-on.

Preparation Is Key

To start, clear your crawl space of debris and sharp objects. Having a smooth surface is essential before laying down the vapor barrier. This helps avoid punctures that could compromise its effectiveness.

The next step? Measure twice. Make sure you’ve got enough material to cover your entire crawlspace floor and walls by taking accurate measurements beforehand.

Lay It Down Right

When installing, overlap each plastic sheet by at least 12 inches and secure them together using seam tape. Similar to pieces of a jigsaw, they should be fitted closely together.

You’ll also want to run the plastic up the sides of your crawlspace about six inches above outside grade level – this gives an extra layer of protection against moisture creeping in from all angles.

Anchoring Your Barrier

Crawlspace Makeover recommends anchoring your vapor barrier every three feet with landscape fabric pins or poly pegs.

They keep everything firmly in place while creating minimal holes that won’t impact performance.

Remember: patience is key here.

Don’t rush through this process because hasty work can lead to gaps or tears that defeat the purpose entirely.

To wrap things up (literally), secure the plastic to your crawlspace walls with a termination bar or foundation pins. These will hold everything in place and ensure it doesn’t sag over time.

Pro Tip: Get It Checked

Finally, once you’ve installed your plastic for vapor barrier, have a professional come in for an inspection. They can spot any potential issues that might cause problems down the line.


Key Takeaway: 

First, clear out your crawl space, then measure twice – accuracy is key here. When laying the sheets, overlap them by 12 inches and secure them with seam tape for extra strength. To keep it stable, anchor the barrier every three feet using pins.

Common Mistakes When Installing Plastic Vapor Barriers

Overlooking Surface Preparation:

We’ve seen it too often. Folks get their hands on a roll of plastic and dive straight into the installation, but that’s like building a house without prepping the land first.

Your crawl space must be free from sharp objects or debris that could puncture your barrier. Ensure you’re not making this mistake by doing some basic prep work.

Saving Pennies on Inferior Material:

You wouldn’t skimp out on quality when buying something important like car tires, right? The same logic applies here.

Cheaper isn’t always better – in fact, using low-grade mil plastic for vapor barrier can lead to more costs down the line due to damage and repairs. Don’t fall for cheap materials; instead, use high-quality vapor barriers such as Crawlspace Makeover.

Improper Sealing:

The smallest gap in your vapor barrier is an open invitation for moisture – think of it as leaving your front door wide open during a rainstorm.

To keep humidity at bay, ensure all seams are sealed with waterproof tape and edges extend onto walls. Need help with sealing? 

Here’s an informative guide about proper vapor barrier installation.

Forgetting about Insulation:

Imagine wearing a raincoat but no sweater in the middle of winter – that’s your crawl space without insulation. A vapor barrier blocks moisture, but insulation is crucial to control temperature and increase energy efficiency.

To get this right, use suitable crawl space insulation.

Solo Installation:

Many homeowners and business owners are tempted to handle the installation of a vapor barrier on their own. This DIY approach is often seen as a cost-saving measure, but it can lead to serious issues down the line.

Vapor barrier installation isn’t as simple as laying plastic sheets across your crawlspace. It requires understanding moisture control principles, material properties, and proper sealing techniques. Without this knowledge, you risk creating conditions that promote mold growth or structural damage due to trapped moisture.

Why Professional Installation Matters

Professional installers like Crawlspace Makeover have the training and experience to avoid these common pitfalls. 

They know how to assess your property’s specific needs, select the right materials, and apply them in a way that provides maximum protection against moisture damage. In addition, they can provide other services like crawl space encapsulation, further enhancing your home or business’s overall resilience.

In conclusion, while DIY installation of vapor barriers may seem appealing due to perceived cost savings initially, it often leads to more problems down the line when not done correctly. It’s best to leave this task in professional hands for optimal results.

Best Practices When Working with Mil Thickness of Plastic Vapor Barriers

When it comes to the mil (thickness) of plastic for vapor barriers, some practices can make your job a lot easier and more effective.

The first step is always choosing the suitable material.

You want to use a standard 6-mil or thicker polyethylene sheeting, like 12 – 20-mil, resistant to tears and punctures. You might find cheaper alternatives out there but remember: quality over quantity. 

Here’s an excellent guide on Crawlspace Moisture Control from EPA, which gives you more insights into choosing the best materials.

Laying Down The Barrier Properly

Your next task is ensuring the proper installation of the barrier.

Cover Everything

Cover all exposed ground in the crawlspace with your chosen plastic sheeting. But don’t just stop at covering; overlap each piece by about 12 inches for seamless protection against moisture.

Taking Care Of The Walls And Piers

The walls and piers need love, too. Attach a vapor barrier to them using mechanical fasteners such as furring strips or special adhesives designed for this purpose.

Just be sure not to pierce through our beloved vapor barrier while attaching.

Firm Sealing Is Essential

Remember folks, sealing those seams tightly makes all the difference. A good seal prevents moisture seepage between overlaps. So get down there and use construction-grade tape for firm sealing.

And hey. If you ever have any doubts during installation – contact Crawlspace Makeover for a professional vapor barrier installation service in Nashville, TN.


Cost Considerations When Using Mil Plastic Vapor Barriers

When planning a crawlspace makeover, it’s essential to consider costs. The choice of a vapor barrier can significantly impact your budget.

Polyethylene vapor barriers range in price depending on thickness, with 6 mil being at the lower end and 20 mil at the higher end. But don’t be tempted by cheaper options. 

A thicker barrier might cost more upfront but will save you from potential moisture damage repairs down the line.

The Long-term Savings of Quality Vapor Barriers

A high-quality vapor barrier like 20 mil plastic, though pricier, pays for itself over time. It provides superior durability and longevity compared to thinner alternatives.

Budget-friendly options may seem attractive initially, but remember – you get what you pay for. Going cheap could mean dealing with frequent replacements or unexpected repair bills due to inadequate moisture protection.

Pricing Variables: Size Matters.

The size of your crawlspace also impacts how much material you’ll need. Calculating this accurately requires precise measurements—underestimating can lead to costly reorders, while overestimation means wasted materials and money.

Labor Costs: DIY vs Professional Installation

You have two choices: roll up your sleeves or hire professionals. Doing it yourself could save some bucks if done right; however, mishaps may increase expenses later on.

Hiring professional help guarantees correct installation – no wrinkles or gaps that let in dampness—but this comes with labor costs attached, too. Professional encapsulation services can provide an accurate quote, ensuring no surprise costs down the line.

The Bottom Line: Cost vs Value

In conclusion, consider both immediate and long-term expenses when choosing your vapor barrier. A quality mil plastic barrier is a worthy investment for its durability and effectiveness against moisture damage.

Remember, opting for a cheaper solution might feel like saving money now. But down the road, it could cost you more because of constant replacements or potential mold removal services.


Key Takeaway: 

Don’t just consider the initial cost when picking a vapor barrier for your crawlspace. Yes, less thick plastic barriers might save you money now, but they may not resist moisture damage in the long haul. This could lead to additional expenses down the line for fixes or replacements. 

FAQs About Mil Plastic for Vapor Barrier

What kind of plastic do you use for a vapor barrier?

Polyethylene plastic is typically used as a vapor barrier due to its water-resistant properties.

Can you use any plastic for a Vapor barrier?

No, not all plastics are suitable. You need one that’s durable and resistant to moisture, like polyethylene.

Can I use 4 mil plastic as a vapor barrier?

You can, but it’s less effective. For better protection, use thicker options like 6-mil or higher polyethylene sheeting.

Is clear or black plastic better for a vapor barrier?

The color doesn’t affect performance; both work fine. However, black may be more UV resistant if exposed to sunlight in your crawl space.

plastic for vapor barrier

Thickness Matters: The Optimal Mil for Vapor Barriers

So, you’ve dived deep into the mil thickness of plastic for a vapor barrier. It’s not just any old plastic – it’s a guardian against moisture damage. 

You’ve learned about its many benefits and how it fights off mold growth and keeps crawl spaces dry.

We explored different types available and how to pick what suits your needs best. For the standard thickness, choose the bare minimum of 6 to 8-mil, while for a more durable option, opt for the 12-20mil poly plastic sheeting for your vapor barriers.

We gave some tips on installation, pointed out common pitfalls, and shared best practices to follow.

Lastly, we discussed cost considerations so you can plan accordingly without breaking the bank.

All in all, remember this: A good vapor barrier is an investment in comfort and safety. Choose wisely!

For professional vapor barrier installation and crawlspace encapsulation services, contact Crawlspace Makeover today!

Picture of Greg Lewis

Greg Lewis

Greg Lewis is the founder and CEO of Tier Restoration, a company dedicated to restoring the indoor environment of homes and businesses experiencing water damage, smoke damage, or mold contamination.

Greg has spent most of his life working in this industry in Nashville, Tennessee, in the 1970s, working in his father’s commercial cleaning business, in the 1980s and 1990s as a partner with his father in the Sears Carpet and Duct Cleaning franchise, then on his own since 2000.

Greg played his trumpet at Overton High School and the University of Tennessee, Chattanooga, and you can still find him playing throughout the Greater Nashville, Tennessee area.