Is It Better For a House to Sit On a Slab or Crawl Space?

Is It Better For a House to Sit On a Slab or Crawl Space? blog header image

Your home’s foundation plays a crucial role not only in its structural integrity, but in its energy efficiency and overall health as well. Both slab and crawl space foundations are popular throughout Maryland and Delaware—but the question is, which one is better?

At Total Home Performance we’re BPI-certified, which means we specialize in the performance of your entire home—and that includes your foundation. Find out the importance of a solid foundation and what’s better for homes in our service area.

Why Your Home’s Foundation Matters

The primary function of a foundation is to hold your house up and keep it from sinking into the ground. However, a foundation does a lot more for your home than that, including:

  • Insulation - Your foundation contributes to your home’s thermal envelope and can either help or hurt how well it holds consistent temperatures.
  • Moisture Control - Too much moisture in a home can cause severe structural damage and wood rot. Your foundation acts as a barrier between your home and the ground, keeping moisture out of vulnerable areas like your rim joists. 
  • Maintained Stability - Without a foundation your home is susceptible to movement caused by the natural fluctuations of the soil, temperatures, and water table surrounding it.
  • Pest Control - The ground below your house is home to insects and other pests, and without a foundation they will have easy access inside and potentially cause serious damage, indoor air quality issues, and more. 

Slab foundations are usually made from concrete that’s between 4-6 inches thick. The “slab” of concrete is often placed directly on the ground, though it can sometimes lay on a layer of sand that assists in drainage around your home. Slab foundations should always be placed on level ground and be custom-designed for your home site.

Crawl space foundations are usually made of stacked concrete blocks or solid concrete walls. They are built up to 4 feet above the ground and most often have walls for additional support. Since crawl space foundations are above the ground line, they do not require the ground underneath to be level, making them a good option for home sites on sloped land. Crawl spaces are usually unfinished, but often hold a home’s wiring, ductwork, and HVAC equipment. 

Slab vs Crawl Space

When choosing between a slab or crawl space foundation for your home, there are several factors to consider. 


Since slab foundations are made up of concrete, they can last over 100 years—that is, if they’re constructed right the first time. Slab foundations are also vulnerable to shifts in the soil, tree roots, and natural disasters that can cause them to crack, threatening the structure of your home.

A crawl space foundation generally isn’t as durable as a slab foundation, however how long it will last depends on the materials used and the quality of its construction. Crawl space foundations are more reliable in areas with shifting soil since your home is above ground.

Price & Installation

Slab foundations require some excavation work, though the installation process is generally easier and cheaper. Since you are basically adding a mini-basement to your home, crawl space foundations take longer to build and are more costly to install.


Slab foundations don’t usually require much maintenance—however, if they crack or suffer from other damage the repair process is much more complex and expensive. 

Crawl space foundations are prone to moisture issues that can lead to structural damage to your home, but with proper crawl space maintenance these issues can be alleviated. Additionally, in the case that moisture does find its way into your foundation, crawl space repair is easier and cheaper. 


Since a slab foundation sits directly on the ground, freezing soil and flooding make it less than ideal in areas like Maryland and Delaware. 

The footings on crawl space foundations usually go beneath the frostline in the ground, keeping your home’s structure safe from colder temperatures and frozen soil. Your home will also be above ground, meaning that your living spaces are also above flood zones. This makes crawl spaces a smarter choice for homes in Maryland and Delaware..

Energy Efficiency

While slab foundations have less space for unwanted air and heat transfer to occur, they don’t usually include insulation. This can make them prone to energy loss through the lower levels of your home. 

A properly insulated crawl space foundation that is included in a home’s thermal envelope is much more energy-efficient and can even provide energy savings year-round. 

Keep Your Home Safe With Crawl Space Encapsulation

Overall, a crawl space foundation is the best choice for homes in our area, but it does require a few extra steps to maximize its efficiency and durability. If your home has a crawl space or you are planning to build one, the best way to make sure your home is secure is with crawl space encapsulation.

Starting with an inspection of your home’s crawl space, the expert team at Total Home Performance will address any risks of moisture, pests, or standing water. We’ll then cover the floor and walls with a heavy-duty vapor barrier before using spray foam to both air seal and insulate the area to keep excess moisture at bay. Finally, we’ll install a dehumidifier in order to ensure the humidity levels in your crawl space stay in the EPA recommended range of 30-50%. 

Crawl space encapsulation can have many additional benefits for your home as well, including:

  • Lower heating & cooling bills
  • Reduced risk of mold
  • Better indoor air quality
  • A more comfortable home
  • And more!

Total Home Performance: Your Local Crawl Space Experts

We’ve been helping families in the Chesapeake Bay area with their whole-home efficiency and healthy home projects since 2009. Our highly-trained team can help make sure your home’s crawl space foundation is dry and secure, just the way it should be. We can even help you save up to $7,500 with Home Performance with ENERGY STAR rebates!

Ready to get started? Schedule your crawl space inspection today. Call [custom:phone-number] or contact us online.

Slab or crawl space?

Find out what’s best for Maryland & Delaware!