Home Crawl Space Average Cost of a Vapor Barrier

Average Cost of a Vapor Barrier

The vast majority of homes in the United States will experience problems with flooding and/or moisture at some point. Your house is only as watertight as its weakest point, which is why you should consider waterproofing your basement or crawl space. For cost information on various waterproofing methods, see our page on the Average Cost to Waterproof a Basement.

Water entering your home from the outside is bad for several reasons, including the following:

Structural damage to your home

  • Damage to furniture, fixtures, and fittings
  • Mold
  • Pests
  • Health problems for residents
  • Damage to electrical wiring (and the danger that causes)

In general, therefore, water in your home is something you want to avoid wherever possible. On top of all of the negative effects of moisture, the cost of repair can be extremely high, ranging from hundreds of dollars to tens of thousands. This makes investing in a vapor barrier to protect your home a sound financial decision.

As the name suggests, a vapor barrier is a material that prevents water vapor from passing through it. They are most commonly made of plastic or foil sheeting and are installed into the walls or ceiling of a home, most typically in a basement, in order to provide an additional layer of protection against water encroachment.

Vapor barriers can be used in conjunction with materials such as concrete, laminate flooring, wood, or even drywall. Vapor barriers are not complex bits of equipment and are fairly easy to install.

This guide will discuss the different types of vapor barriers you can buy, as well as the additional expenses, and some alternatives you can consider.


Overall, the average cost of installation for a vapor barrier is between $1,200 and $4,000. This includes materials and labor. Prices for materials vary more than those for labor (see the costs of different thicknesses, below, for an outline of different labor costs).


The thicker the vapor barrier material, the better protection it provides. This results in a higher cost for the material. The table below breaks down the cost per roll and per square foot for different thicknesses.

Thickness (mm)Cost per Roll(1,200 square foot)Average Costper Square Foot
6$160 to $200$ 0.15
8$200 to $230$ 0.18
10$230 to $300$ 0.20
12$300 to $350$ 0.30
20$350 to $500$ 0.50

The decision on which is best is totally based on your budget. For a 20 millimeter thickness, you will pay more than three times the price of a 6mm thickness barrier.


Along with the actual vapor barrier materials and labor, you will need to pay for a number of additional materials. If you are working with a contractor on a fixed fee, some of these costs will be bundled into the overall project cost. However, if you are doing the work yourself, you’ll need to factor in the below costs.

Before you start the project, calculate the total cost of all of the materials. This will give you a sense of whether it’s actually financially viable to do the work yourself. In many cases, a contractor’s price may seem high, although once you add up all the elements, there’s a lot less difference in price.


The tape is a crucial part of the process since it secures the vapor barrier in place. You cannot use tape you may have around your household – instead, you need to use special vapor barrier tape. The tape effectively becomes part of the vapor barrier, since it seals the edges of the barrier. As mentioned above, the whole process is only as strong as its weakest part, so getting the right tape is critical.

For a 4-inch wide, 180-foot long roll of tape, you’ll pay around $50. Therefore, for the average crawl space, you’ll pay between $120 and $200 in tape costs.


Although not strictly a part of the vapor barrier process, installing a dehumidifier is usually a strong part of the moisture-prevention process. A dehumidifier will help to remove any residual water or any that is able to permeate the vapor barrier.

Installing one will draw the moisture out of the air and will keep your room comfortable and prolong the life of your furniture, fixtures, and fittings.

To install a permanent dehumidifier will cost between $780 and $1,000. This does not include installation. Alternatively, portable dehumidifiers cost between $175 and $275 and require no installation – although they can be a little unsightly if you’re leaving them in the corner of a room. To compare top dehumidifiers, go to our page on Best Dehumidifiers for Basements.


As the table of thickness vs. price (above) suggests, the more barrier you have, the better. One tactic you can use is to use multiple vapor barriers in construction. If a contractor is installing multiple vapor barriers, they will usually charge based on the overall thickness of the barrier.

Generally, you can expect to pay between $0.25 and $1.50 a square foot, or $375 to $2,250 for a 1,500 square foot space for multiple vapor barriers.


Crawl spaces are some of the most vital parts of your home in which to install vapor barriers. Because they are below ground, it is very common for water to enter crawl spaces from the surrounding earth.

The prices for installing a vapor barrier for a crawl space are usually done on spec by contractors, based on the following factors:

  • Size of crawl space
  • Accessibility
  • Quality of materials desired

For a 1,500 square foot crawl space, you can expect to pay somewhere between $1,000 and $3,000. A contractor will usually work on a fixed price basis for this project, so if you are budget-conscious, get multiple quotes, and talk about options for reducing costs, such as using cheaper materials.

Dehumidifier$175 – $275
Multiple VaporBarriers$.25 – $1.50per sq. ft
Crawl Space$1,000 – $3,000


If a vapor barrier is too daunting a prospect for installation, either for financial or time reasons, there are alternatives you can use. Although this may not be as effective as a full vapor barrier, these may stop moisture enough for you to address the most pressing part of the problem. In addition, any long-term solution to a moisture problem will involve a multi-pronged approach to be the most effective.

Vapor Retarder Paint

Instead of using a vapor barrier, you can buy vapor retardant paint. This is a paint that covers a surface (usually an interior wall) and provides a waterproof barrier. For a one-gallon can of vapor retardant paint, you can expect to pay between $20 and $40 at a hardware store.

For a five-gallon can, you will pay between $60 and $90. It is worth buying a five-gallon can and using multiple coats, as this will give you a higher level of protection.


Although vapor barrier material is specially designed to protect against moisture as efficiently as possible, you can improvise your own using more readily available material. Basic polyethylene plastic sheeting (either black or clear) of the sort used in yard work or home maintenance will work to provide some level of moisture protection if installed properly.

The benefit of this approach is the price – this material usually costs between $0.05 and $0.20 per square foot, giving a total cost of between $75 and $300 for a 1,500 square foot room.

Repairing Drainage System

As mentioned above, you need a multifaceted approach if you are to stop moisture from entering your home. One of the most important parts of this process is preventing water from entering your home in the first place. A drainage system will help to shift water away from the edge of your home.

A broken drainage system is one of the primary causes of moisture entering a home, and will quickly overwhelm a vapor barrier. To fix a drainage system outside your home, you can expect to spend between $500 and $4,000. This can range from something as simple as restoring your gutters, to landscaping your entire yard to create a slope away from your house.


Vapor RetardantPaint$20 – $40 forone-gallon can
Sheeting$0.05 – $0.20per square ft.
Repairing DrainageSystem$500 – $4,000

Installing a vapor barrier is not the most glamorous way to spend $1,200-$2,000. However, it will often save you money in the long term. If you’re looking to keep your house free from water, it’s one of the most cost-effective ways you can prevent water from entering through your foundation

Vapor barriers work well with other forms of waterproofing, such as exterior landscaping or installing a French drain. A combined approach will give the best results. A vapor barrier is not totally leak-proof but is certainly an advantage, particularly for below-ground spaces like basements and crawl spaces.

Given the cost of repair for moisture in your home is likely to be $500-$700 at the bare minimum, a $1,000 investment will likely pay for itself.

Although it’s difficult to quantify precisely – after all, if you install a vapor barrier and then don’t experience damage from water, you have nothing to weigh the cost against – you can also consider the increase in the overall value of your home.

A vapor barrier may not be the ideal way to spend a couple of thousand dollars, but it will reap financial benefits in both the short and long term.

Leave a Comment