How much does it cost to insulate a crawl space?

Reviewed by Cristina Miguelez remodeling expert. Written by Fixr.com.

A crawl space is the narrow unfinished area between the first floor of a home and the ground. While traditionally, crawl spaces were unfinished and uninsulated, it has become more common to insulate these spaces to help with utility costs and comfort. The floors directly above the crawl space will be warmer and more comfortable when the area is insulated. The cost of insulating a crawl space depends on the type of insulation used and whether it is new construction or an existing home.

The average cost for crawl space insulation is $500 to $6,000. The national average is $2,000 for spray foam insulation in an 800 sq.ft. crawl space. On the low end, it costs $300 to insulate a small 300 sq.ft. crawl space with batt insulation. On the high end, it costs up to $10,000 to insulate a large 1,500 sq.ft. with spray foam in the walls and subfloor and a vapor barrier.

Cost to Insulate a Crawl Space

Crawl Space Insulation Cost per Square Foot

When it comes to crawl space insulation, most professionals price this project by the square foot because that is the easiest way to calculate the material and labor costs. The square footage of a crawl space depends on the size of the house and the layout. The average cost to insulate a crawl space per sq.ft. is between $1 and $5. The table below shows the cost of the most common crawl space sizes.

Average Cost of Crawl Space Insulation by Type

Crawl space insulation costs vary by the type of insulation. Contractors can recommend the best type of insulation for your home design and climate because some insulating materials are better at preventing heat loss or moisture buildup than others. While batt, roll, foam board, and spray foam are recommended for crawl spaces, blown-in insulation is not due to the tight space. The table below shows the average cost per square foot to install different types of crawl space insulation.

Crawl Space Batt Insulation

If you want batt insulation for your crawl space, expect to pay around $1 and $2 per sq.ft. Batt insulation is made of mineral wool or fiberglass cut into flat pieces with a paper or foil facing. The cheap cost is attractive to many homeowners. However, the R-value is not as high. It is best to use this kind of insulation in a mild climate where insulation and temperature control are not as big of a priority.

Crawl Space Roll Insulation

Crawl space roll insulation is similar to batt insulation, costing $1 to $2 per sq.ft. While batts need to be installed in pieces, rolls can be rolled out to cover the walls and ceilings. There is not much room for gaps between sections of insulation, so rolls may sometimes be more efficient than batts. Most contractors recommend cost-effective roll insulation for dry subfloors.

Crawl Space Foam Board Insulation

The rigid foam or foam board insulation crawl space price is between $1 and $4 per sq.ft. This foam board insulation may be made of expanded or extruded polystyrene or polyisocyanurate. While the cost can add up, many homeowners find rigid foam a worthwhile way to insulate the ceilings and floors of a crawl space. Its high R-value minimizes thermal bridging, stops air leaks, and keeps moisture under control.

Crawl Space Spray Foam Insulation

The cost to spray foam a crawl space ranges between $2 and $5. Closed cell spray foam is considered one of the best insulation types for crawl spaces. However, this quality makes it a more expensive option than open cell, which allows for more air circulation. Either way, spray foam is applied in the rim joists and ceiling to ensure an airtight seal and reliable moisture barrier. What is good about closed cell spray foam is that it adds strength to the walls and does not lose its R-value over the years.

Crawl Space Insulation Price by Material

Many materials are used to insulate homes and buildings, but some are unsuitable for dark, cramped crawl spaces. Suitable crawl space insulation materials come in several applications, such as crawl space fiberglass insulation or rockwool insulation, which is supplied in batts. These materials are often combined with polyisocyanurate or polystyrene spray foam or rigid foam board for optimal warmth and performance of crawl space insulation. Denim/blue jean, rockwool, and sheep wool also come in batts. This makes them easy to install but not quite as effective as foam-based insulation, which provides an air barrier. Cork and wood fiber rigid boards offer a high level of insulation and moisture protection. The below table outlines different crawl space insulation materials, application type, and average costs per square foot.

Labor Cost to Install Insulation in a Crawl Space

Professional insulation installers handle all aspects of the crawl space insulation, which begins with an inspection to understand the size and design of the space. This helps them provide an estimate of the overall insulation costs, which are most commonly charged per square foot. In most cases, only one or two workers are needed for the crawl space insulation job due to the tight size and difficult access. Prep for this project includes cleaning out the space and checking for loose wiring or wood rot that must be addressed before the insulation is installed. The labor cost to insulate a crawl space ranges from $0.25 to $2.50 per sq.ft. This means the total project with materials and labor costs from $1 to $5 per sq.ft. Sometimes, insulation professionals may charge $40 to $60 per hour, but this is not as common as charging by the square foot. This usually includes the project estimate and initial inspection, prep work and clean-up, and ideally, a lifetime warranty and assistance with applying for energy rebates.

Cost to Replace Insulation in a Crawl Space

Crawl space insulation replacement costs $1,000 to $3,500 for an 800 sq.ft. crawl space. This cost includes the removal of the original insulation and the new materials, which may be the same as before or an upgraded insulation material that lasts longer. There are a few signs you need new crawl space insulation, including cold floors or noticeable damage to the existing insulation. If you have water damage, frozen pipes, or a pest infestation, you likely need new insulation. If your energy bills are high and your pipes regularly freeze, you may want to have a professional look and see if the crawl space insulation needs replacing.

Remove Insulation From a Crawl Space

Removing old insulation from a crawl space is recommended before installing new insulation. While replacing old insulation is not required, an uninsulated crawl space may result in higher energy bills and colder floors above the area. That is why most homeowners opt for full removal and replacement to keep their homes warmer and lower energy bills. Just removing damaged insulation on its own costs between $300 and $1,000, with the total crawl space insulation removal cost depending on the type and the size of the crawl space.

Maintenance

The homeowner may do general crawl space maintenance such as sweeping and cleaning to help with air quality and comfort levels. Professionals provide crawl space maintenance through inspections and recommended insulation or encapsulation services to protect the area from damage. Experienced contractors are the preferred choice for finding maintenance issues lurking under the house, such as problems with electrical wiring, plumbing, ventilation, or even cracks in the foundation. Maintenance professionals will address mold, mildew, pests, and moisture concerns. Insulation or encapsulation is the best way to control such maintenance issues and keep the crawl space protected from moisture and insects.

Pros and Cons

As with any home project, there are pros and cons when insulating a crawl space. One of the biggest benefits is lower energy costs because of the high R-value of closed-cell spray foam insulation. This makes it extremely effective at reducing heat loss and maintaining a comfortable home temperature without turning up the AC or heater. Also, crawl space insulation minimizes cold drafts along baseboards and prevents burst pipes during freezing temperatures. Closed-cell spray foam is a great insulator and a successful moisture barrier that reduces humidity and stops mold outbreaks.

Although all of these benefits make crawl space insulation a sensible choice for many homeowners, there are a few possible downsides. One, of course, is the cost. Although crawl space insulation is cheaper than encapsulation with full vapor barriers to prevent water damage, it still costs between $500 and $6,000. You will likely need to plan for this project and decide if it is worth the cost. Also, insulation is suitable for small leaks in a crawl space. However, if you have major leaks and water damage, insulation may not be worth it.

Crawl Space Encapsulation vs Insulation Price

To improve the energy efficiency of your crawl space, you can choose between insulation and encapsulation. Thermal insulation is ideal for keeping the crawl space warm and free of excess moisture. Insulation keeps heating and cooling costs down because the air will not escape from the house. Insulation makes a barrier between the outside and inside, protecting the pipes and reducing moisture buildup around your home’s foundation. The walls, ceiling, joists, and subfloors are the most likely areas of the crawl space to be insulated.

Insulation costs between $500 and $6,000. A slightly more expensive option called crawl space encapsulation Is priced between $2,000 and $8,000. Crawl space encapsulation follows a similar process to insulation installation, except for installing vapor barriers around the entire crawl space to stop water from getting in altogether. Often a dehumidifier will also be installed, ensuring homes in high moisture areas are protected from water damage. If you have ongoing moisture problems in your home, crawl space encapsulation may be the better choice. Otherwise, insulation is a great idea to keep energy costs down.

Enhancement and Improvement Costs

Mold in a Crawl Space Removal

Crawl space mold remediation costs between $500 and $2,000. The crawl space square footage and level of mold growth influence the final cost. Mold grows in crawl spaces, much like in basements, due to high humidity and dampness. Luckily, the smaller contained spaces and increased ventilation means mold should not spread as much as it would in the basement. If you notice wood rot, warped or water-stained baseboards, or black or green spots on the crawl space walls and insulation, it is time for mold remediation.

Install Vapor Barrier in a Crawl Space

Installing a crawl space vapor barrier costs between $1,500 and $4,000. The price varies depending on how much material is needed to create the vapor barrier, which minimizes humidity and moisture build-up. This worthwhile investment prevents rot, mold, and water damage in the crawl space.

Crawl Space Dehumidifier

If you want a crawl space dehumidifier to keep humidity down, plan to pay around $750 to $1,700. This is a good idea if you live in an area with high rainfall and humidity because the dehumidifier prevents mold growth, protecting the integrity of your home and avoiding expensive mold removal.

Additional Considerations and Costs

• License. Make sure the crawl space insulation installer is fully licensed and insured. Working in confined spaces requires a high level of safety and attention to detail, so you want a reputable professional on site.
• Permits. Contractors must meet local building codes and permit requirements to work on your crawl space insulation.
• DIY. It is not recommended to DIY crawl space insulation, mainly because this is a very tight area with limited entry. There are inevitable safety concerns when working in a cramped area like the crawl space. A professional can handle this task much more efficiently.
• Prep-work. As part of the prep for crawl space insulation, professionals will make sure the space is clean with no obvious water or structural damage. Once the crawl space is clean, then the insulation installation can begin.
• Warranty. Most companies offer a lifetime warranty on crawl space insulation. Always ask about the warranty before work commences.
• New vs existing construction. It is easier to install crawl space insulation in a new home where the area is more accessible. It may cost more and take longer to install insulation in an older house where contractors must deal with existing insulation and drywall.
• Vented vs sealed crawlspace. Encapsulated or sealed crawl spaces are often preferred to open or vented areas. That is because sealed spaces are closed off to outdoor air, so they control moisture better. It costs less to insulate them, too.
• Location. The cost to install insulation in the crawl space depends on whether you insulate the whole crawl space or just one part. While most professionals recommend insulating the entire area for the best results, some homeowners opt to start with just crawl space wall insulation or subfloor insulation. Insulating the walls and subfloor costs slightly more than the cost of insulating ductwork or floor joists in the crawl space.
• Air leaks. It is important to stop air leaks in the crawl space with sufficient insulation. Ask your professional installer what type of insulation they recommend for your home and region.
• Thickness. Spray foam insulation may be installed in the crawl space with several different thicknesses. The thicker the insulation is, the more it will cost. Look for an R-Value of 21 or higher for the ideal insulative protection.
• Faced vs unfaced. If you want a vapor barrier for enhanced protection against moisture buildup, faced insulation batting in the crawl space is ideal. Faced insulation is more expensive than unfaced insulation by $0.10 to $0.25 per sq.ft.
• Climate. In the U.S., R-19 is the recommended crawl space insulation level, although homeowners in mild climates may make do with R-13 or R-15. It costs more to have a higher insulation level.
• Repair. If you have damaged insulation, particularly sagging insulation that has created gaps in your crawl space barrier, it may need to be repaired or replaced. Most of the time, replacement material works the best and is not much more expensive.