How Do Floor Joists Support My Home?

If your home was built on a crawl space, it relies on a floor joist system to support the structure. This is crucial, so the system must be properly built and well-maintained to ensure the home’s stability.

Unfortunately, wooden floor joists can easily succumb to crawl space moisture and other damage. But, all is not lost; local crawl space repair professionals can help shore up these essential fixtures and safeguard your home against moisture.

Let’s take a closer look at floor joists, their purpose, different types, and potential problems that could harm them.

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What Are Floor Joists?

If you have ever witnessed a house being built, you have probably noticed the wooden frame that goes on top of the foundation. A floor joist is a flat structure that stiffens the subfloor shearing when combined with the floor framing.

These beams are installed after the crawl space or the basement–depending on the type of foundation–has been completed. When everything is in place, floor joists support the floor above. These beams need to be parallel and equidistant.

Installing floor joists is not a DIY project. A skilled professional should choose the right type of joists and install them on the subfloor.

3 Common Types of Floor Joists

There are three types of joists contractors use when building a house, each with pros and cons:

1. I-Joists

This is an eco-friendly option since I-joists are not entirely made of solid wood. Instead, the ends are made from solid wood, while the middle is made of OSB or plywood.

These floor joists look like the letter “I”, hence their name. They can extend over 20 feet and have a higher weight load capacity. This is why they are great for tile flooring. Some variations come with predrilled holes in them, which are used for holding utility lines.

2. Solid Lumber

Before construction materials were so advanced, solid lumber joists were the only possible option. Although their price depends on several factors, including size, wood grade, and wood type, this option is more affordable. This type of joist holds up well against fires, and when it is used in construction, it is important to follow local codes and keep holes for utilities in mind.

3. Open Web Floor Trusses

These joists are made from 2 x 4 boards and look like a web of diagonal boards. These boards are connected with plates that keep them in place. Since there is room between diagonal boards, open web floor trusses make it easy for builders to run utilities right through them.

Another advantage of floor trusses is they are much easier, quicker, and economical to install than I-joists or solid lumber. They also stretch more than other joists due to their unique design.

Signs of Failing Floor Joists

The problem with floor joists is that they are made of wood, and like any wooden structure, they can suffer significant damage, such as rot and decay. Look for these signs:

Uneven floors
Sticking windows and doors
Sagging crawl space supports
Rotting and moist wood
Cracks in your drywall
Creaking floors

Do not try to fix this kind of damage on your own. Some types of joists require a professional contractor or carpenter. If you notice any of these signs, call an expert to assess the problem and recommend repairs.

Causes of Floor Joist Issues

Several factors can cause problems with floor joists, including:

rotting wooden joist and corroding supports

Poor Design: If the builder didn’t use enough floor joists or incorrectly calculated the spacing, the joists won’t serve their purpose.
Your Home’s Weight: When building a home, contractors make calculations based on the original size of the house. If you decide to add another story, keep in mind you might end up with a cracked floor joist.
Moisture and Humidity: Waterproofing your home is necessary because moisture and water damage can lead to all sorts of problems, floor joist failure included.

How to Fix Floor Joist and Moisture Issues

Address broken floor joists with help from experienced contractors as soon as possible. If your floor joists are damaged beyond repair, it is time to replace them completely. This is a costly investment, so fixing the problem as soon as you notice it is always better.

If your floor joists cannot support your home on their own, don’t panic. Solutions such as adjustable crawl space support jacks can stop your floors from sagging. Additionally, encapsulating your crawl space is crucial. A quality vapor barrier keeps moisture out, prevents rot, discourages pests, and promotes healthy air circulation.

Need Floor Joist & Crawl Space Help? Contact Us Today!

Damaged floor joists can become a safety hazard, so it is important to take action as soon as you notice the first signs of trouble. Call experts at Tar Heel Basement Systems and schedule a free inspection today.

Our experienced team will complete a thorough inspection of your home to determine the cause of the problem and recommend solutions tailored to meet your unique needs.

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Floor Joist FAQs

Will joist damage go away over time?

The longer damaged joists sit in your crawl space, the more dangerous that damage is going to become. Unaddressed moisture leads to wood rot, pest damage, structural instability, decreased home value, and unsafe living conditions for your family. It’s best to contact crawl space professionals like Tar Heel Basement Systems as soon as you notice problems like sagging and uneven floors.

Should I repair floor joists on my own?

While DIY work can be great in some areas of the home, DIY crawl space repair can be expensive and dangerous. Professionals have the right tools, training, safety gear, and solutions to fix the problem the right way the first time. Contact us today to learn more and schedule a free inspection.

How much does floor joist repair cost?

The cost varies depending on the extent of damage, crawl space size, and necessary repairs. Our team at Tar Heel Basement Systems values transparency, and we provide you with detailed costs and financing options during a free crawl space inspection.

Holly Richards-Purpura

Content Writer

Holly is a Content Writer for Groundworks who has written and edited web content for the foundation services industry for almost 10 years. With a background in journalism, her passion for the written word runs deep. Holly lives in Columbus, OH, with her husband. Along with educating homeowners, she also has a big heart for the Big Apple.