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Components of a Crawl Space: Homeowner’s Guide

Your crawl space is far more than just an empty space underneath your home. In fact, it contains a wide range of crawl space components that are vital to ensure structural integrity, prevent moisture issues, and maintain a comfortable home. Here’s what you should know about crawl space components.

Crawl Space Access Point

Crawl Space Access Point

Every crawl space needs an access point for inspection and maintenance. While local building codes vary, your crawl space opening should typically be around 18 by 24 inches. You want your crawl space access point to be easy to access but also protected against pests and the elements.

Foundation Walls

Foundation Walls

The foundation walls are an integral part of the crawl space. They support your home, and the crawl space is the area between them. One of the most important reasons that your crawl space needs effective maintenance is to prevent moisture issues from damaging the foundation walls and affecting your home’s entire structure.

Floor Joists

Your home’s floor is directly above the crawl space, and you can see the exposed floor joists from beneath. These are the horizontal beams that support the floor. 

There are also the band boards that either end of the joists connect to. The band boards and the rim joists (the joists that sit directly on the foundation) are at higher risk of rot and other moisture issues.


Of course, you wouldn’t have much of a home if you had to walk around on joists. There’s also the subfloor that sits on top of the joists. 

The subfloor is typically some type of plywood, providing a flat and even surface for the tile, laminate, carpet, or other flooring on top. You don’t want moisture issues like mold affecting the subfloor and entering your home.

Crawl Space Insulation

Crawl Space Insulation

Crawl space insulation plays an important role in keeping your home comfortable. It is typically installed between floor joists, isolating your floor from the crawl space. Without effective insulation, you can lose heat through your floor into the crawl space.

Vapor Barrier

Moisture is a serious concern for any crawl space. Vapor barriers can prevent this by providing an impermeable layer that keeps water away from wooden structural elements. Large plastic sheets are carefully applied and sealed to keep moisture in the ground from entering the crawl space.

Piers and Supports

Piers and Supports

Piers and supports in your crawl space provide additional support, allowing for longer spans than unsupported floor joists can handle. These vertical columns are typically placed underneath a girder beam that distributes their support across multiple joists.

Plumbing and Electrical Lines

Plumbing and Electrical Lines

You’ll also find a variety of plumbing and electrical lines in the crawl space. This is where they typically enter the home. However, they can also be at risk of damage from moisture and pests, along with being difficult to access and repair.

Ventilation Openings

Ventilation is essential to protect your crawl space from moisture issues. Whether you have a sealed or unsealed crawl space, you need some form of ventilation. For sealed crawl spaces, vents are the only source of airflow. In any case, ventilation regulates moisture and temperature to prevent a wide range of issues.

Sump Pump

If your area is prone to flooding, you may need a sump pump installed in your crawl space. This is an automatic pump that activates when water reaches a certain level. It pumps the water away from your home, preventing it from reaching structural elements. Some crawl spaces that are frequently wet can also benefit from a dehumidifier.

Crawl Space Encapsulation

Crawl space encapsulation is a process that completely seals the crawl space to prevent rot, mold, pest infestation, and a wide range of other problems. It’s the best way to protect your home against these issues in the long run.

Ensuring All of Your Crawl Space Components Are in Good Condition

With so many crawl space components supporting your home, it’s important to ensure each is doing its job properly. You can take advantage of a free inspection from Falcone Crawl Space & Structural Repair to take a proactive approach to maintenance and save on repairs. Schedule your free inspection today.