Got Sagging Floors? The Best Floor Support Jacks for Your Crawl Space

Your crawl space can prove tricky to maintain. Moisture loves to build up in this area. Eventually, the moisture can lead to sagging on your floor.

This sagging can prove unsafe for both you and your family. However, there are a couple of repairs that you can do to remedy this problem.

If you have sagging floors, then one of your first questions is probably, “How do I fix it?” One solution is to use a floor support jack.

There are a lot of options among crawl space support jacks. A few pointers may help you choose the right one. Here, we’ll go over a few of the best floor support jacks for your crawl space.

To learn more about the best support jacks for your floor, keep reading.

What Is a Crawl Space?

If you’re new to property ownership, you may have yet to learn about your crawl space. When buying a home, most people don’t think about what’s right under their feet.

The area below you is especially important if you’re walking over a crawl space. It’s one of the most important parts of your home.

Your crawl space is a hollow area under the floor of some homes. It’s between the ground and the first floor.

Usually, a crawl space is about one to three feet high. This space is just big enough for you to enter the area by crawling, hence its name.

A crawl space elevates your home off the ground. It’s also an unobtrusive and convenient place to hide the guts of your home.

This space will typically hold the components that you’ll find in a basement. These components may include air conditioning, your heater and ductwork. They may also include electrical wiring, insulation and plumbing fixtures.

What Is a Floor Joist?

Floor joists support your floor above the crawl space. They’re an essential element of the structure of your home.

Again, you most likely don’t think about floor joist much. It may surprise you just how many components of your structure are right below your feet.

Some floors sit directly on concrete slabs. If not, the flooring will have a layer of underlayment.

Next, there’s a layer called the subfloor. The floor joist support system will support the subfloor.

Also, a home that’s not on a slab will have a crawl space or basement. These kinds of homes almost always use a floor joist support system.

This kind of system provides weight-bearing support. In fact, floor joists support everything in your home. They hold up furniture, flooring—and most importantly people.

The joist themselves are horizontal framing members. They make up the skeleton of the frame of your floor.

Floor joists span across the entire room. They’re supported at their ends.

In some cases, they’ll also have support in the middle. These kinds of supports are called load-bearing walls or beams.

Load-bearing means that a structure supports everything above it. If you have problems anywhere near a load-bearing structure, you want to repair it right away.

crawl space repair

Sagging Floor Joist Repair

Fixing a sinking floor is relatively straightforward. You’d perform the crawl space repair with a technique called “sistering.” The process involves sistering two joists together.

For example, you may have cracked, sagging or twisted joists. Sistering will provide these joists with extra support.

Of course, you’ll need tools for the project. These tools include a:

• Caulk gun
• Circular saw
• Drill
• Hammer
• Safety glasses
• Tape measure
• Hearing protection

You’ll also need materials. These materials include:

• 16d nails
• Floor jacks
• Wood for the new floor joists

Now, you’re ready to get started.

Sistering the Joists

The first part of the project is to remove electrical cables, pipes and other obstacles. Here, you want to check under the joists that are sagging. Now, you’ll set the new joist alongside the old one.

Apply plenty of construction adhesive to one of the old joists. Now, you can nail the new joist in place.

You’ll want to nail the new joist to the old one with at least three nails every 16 inches along the beam. Repeat the process until you’ve shored up all your sagging joists.

Finally, you’ll need to elevate your sagging floor with a jack—but exactly what is a floor jack, and which one do you choose?

What Is a Floor Support Jack?

A floor jack is a steel structural support. You’d install it underneath your freshly repaired floor beams.

You’ll then adjust the floor jack tightly. This procedure will prevent your floor from sagging.

The Best Floor Support Jacks for Your Crawl Space

You might also hear someone call a floor support jack a “screw jack” or “crawl space support posts.” They work along with the girders that support floor joists.

A floor support jack is a post that enables you to adjust the level of your floor. Manufacturers make it with two heavy-duty steel pipes. The pipes rest one inside of the other.

Usually, the inside pipe is threaded. You might adjust this section by turning a large wing nut.

Also, you can attach it with nails to the underside of the joist. You’d also place the jack on top of a woodblock over the concrete slab or crawl space support piers.

A floor jack is an excellent way to shore up the structure of your home. However, you’ll want the best jack for your needs.

Here, we’ll go over the very best floor jack options on the market.

Tel-O-Post Adjustable Jack Post

The Tel-O-Post Adjustable Jack Post works well for both temporary or permanent support. You can use it below stairs, porches and decks.

It works ideally for supporting heavy load locations and crawl spaces. As a result, it’s a great floor support jack for many home renovation projects.

Tel-O-Post constructs their Adjustable Jack Post using heavy-duty carbon steel. The support is highly rust and corrosion-resistant.

The adjustable support jack has a top and bottom plate. It’s heavily embossed. This feature limits jack movement.

It also minimizes an effect called dishing. In other words, it keeps the jack from bending under the weight of the floor.

Vestil Jack Post

The Vestil Jack Post extends telescopically. It works well for temporary bracing and leveling.

It’s also a great tool for supporting floor beams. Contractors often use the Vestil Jack Post to provide beam support during construction or repairs.

You can modify it to any height within its range. As a result, it’s ideal for many applications.

Vestil constructs their Jack Post using high-grade steel. What’s more, it’s welded for extra strength.

You’d adjust the Vestil Jack Post with a rotating bar and screw bolt. The support also has two dual-lock pins to keep the jack in place. Remember, however, this unit is not for permanent support.


The AKRON PRODUCTS Jack Post is a well-known brand. The floor support jack is ideal for providing temporary or additional support.

It works great for many applications. These applications might include:

• Beneath terraces
• In crawl spaces
• Under staircases

The AKRON PRODUCTS Jack Post provides superior performance for many projects that require supporting heavy loads.

This unit is also made using high-strength carbon steel. The floor jack is designed for maximum safety. It’s also engineered for extreme durability and quality.

Getting Help With Foundation Problems

It’s natural to have concerns about cracked, sagging or twisted floor joists in your home or property. If you see these problems, the best thing that you can do is to call a foundation repair service right away.

The foundation repair service will inspect your floor. They’ll recommend any needed strengthening measures. A foundation repair expert can also give you an idea of floor joist repair cost.

The service’s recommendations will remove any sags from your floor. They’ll also bring the structure of your home up to code. More importantly, a foundation repair service can tell you whether you have additional structural problems.

You want to take advantage of their expertise to find out if any part of your home requires professional repair. Taking care of any serious problems now will save you money in the long run.

The Best Crawl Space Repair Service for Your Home

Now you know more about the best floor support jacks. What you’ll need now is the best crawl space repair service in town.

If you’ve been noticing sagging on your floor, your observation could indicate a more serious problem. Crawlspace Medic will help you get to the root of your crawl space issues so we can fix them before they get worse.

We specialize in crawl space repair and moisture remediation. If you need our services or want more information, please feel free to contact Crawlspace Medic today at (866) 882-7295. Alternatively, you can schedule a free inspection online.


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