What Are Crawlspace Jacks for Foundation Repair?

Have your floors been sagging on your raised foundation more than usual? You may have heard the term “crawlspace jacks” before and want to educate yourself on what they’re for. You want to elevate your knowledge similar to how you want to elevate and support drooping floors.  

If those posts and pads fail in your crawlspace, crawlspace jacks are the perfect alternatives for your raised foundation home. 

Dalinghaus Construction has repaired over 2,000 homes in Southern California, Arizona, and Nevada, whether through stabilizing a home from foundation settlement to supporting raised foundations using crawlspace jacks. Our production crews have endured the creepy crawlies in your crawlspace to support your floors. We understand the things you install – you would hope. We want to elevate your knowledge on crawlspace jacks for when you need your raised foundation repaired. 


What are Crawlspace Jacks? What are they used for?

Crawlspace jacks support girder beams – which support the sub-floor on a raised foundation home. 

They will only be used for homes with raised foundations. 

The four components of a crawlspace jack consist of a base plate at the bottom, a pipe that attaches to the base plate, a threaded collar, and a top plate holding the girder beam. 

They have a load capacity of 60,000 lbs.

Crawlspace jacks can also be referred to as Crawlspace Support Jacks, Subfloor Support Jacks, or Subfloor Support Piers.

The materials are made of galvanized steel, aside from the base. The base will be composed of Polyurethane.

To understand how well polyurethane bases work when installed under your home, let’s put it this way: the stuff is as hard as concrete. And more than durable. 

Installing a crawlspace jack 

How many people does it take to install a crawlspace jack? The same amount it takes to change a lightbulb

It takes one person to install the jack, but there will typically be a team of two. The other person will cut the pipe from the exterior for preparation before installation.

So one person will be at the sight location, and the other will be doing modifications. So one person is like Frodo from The Lord of the Rings tasked with the burden of installation, while the other is Samwise, offering their support and helping see through the project. 

If crawlspace jacks are installed correctly, they will be a permanent solution.


Installation process

  1. Prep the grade.
    1. Grade – To adjust the soil level and elevation. 
    2. The production team will need to ensure the grade is flat and level for easy installation and sturdiness. The polyurethane base will be set on the flat grade.


  2. Cut the galvanized steel pipe.
    1. The pipe needs to be as high as reasonably possible so the threaded collar doesn’t extend too far. 
    2. The pipe is measured by height.


  3. The cut pipe is installed onto the poly base.


  4. The threaded rod is installed.


  5. The top plate is installed on top of the threaded rod.


  6. The threaded rod is tightened (via a threaded collar attached to it) to compress and touch the top of the girder beam.


  7. The top plate is secured to the girder beam with screws.


  8. The production team lifts the girder beam to compensate for any sag or conditions that have put the elevation down.


You’re replacing some bad posts and pads, except with galvanized steel that lasts longer than the wood used for a raised foundation. Even treated wood can still rot out or be exposed to termites. 

Galvanized steel has more trouble rotting out or being eaten by termites. The longevity is much better with galvanized steel. 

Another benefit is if your crawlspace jack needs adjusting at any time, it can be done. We – or whichever company you go with – can come back and do an adjustment. 

Cost of installing crawlspace jacks

Depending on the complexity of the installation, each jack can range from $750-950.

The overall cost would dictate how many jacks will be put in. A general range for crawlspace jack installation will be between $10,000-$15,000

And it’s not the entire foundation that needs its posts and pads replaced with crawlspace jacks. It will only be areas that need to be replaced. So if you have one area of your home with a drooping floor, crawlspace jacks will be placed in that area. 

A 25-year warranty will be put on each pier, even though they should last well beyond that. Again, it’s galvanized steel. It shouldn’t rot out or get damaged by termites. 


“What if I don’t install crawlspace jacks?”

If you don’t mitigate the issue and the sag, you can have continuous sag with the girder beams and the subfloor. 

This will ultimately mean more internal damage in your home and it will have a higher repair cost at a later date. 


See if you need crawlspace jacks installed in your raised foundation.

You’ve learned what crawlspace jacks are, how they’re installed, how much they cost, and what can happen if you don’t install them. See if you need them installed under your home for your raised foundation. That way when the beat drops, the floor won’t drop with it. 

Get a free evaluation with multiple companies. Compare and contrast prices, see the vibe each company gives off, and, most of all, see if crawlspace jacks are necessary for your raised foundation. A repair may not be necessary. Either way, you can get multiple opinions before making any decision. 

You can start with Dalinghaus Construction to have one of our Project Design Specialists give you an honest assessment during our 60-90 minute inspection.

Check out our other crawlspace jacks article Crawlspace Jacks (Installation and Repair).

Look at this article going over the repair process with this piece on Repairing a Raised Foundation With Crawlspace Jacks in Fullerton, CA. These crawlspace jacks used concrete bases instead of the new polyurethane bases, but the installation process works the same. 

For any questions, call Dalinghaus Construction at (877)360-9277, or click the button below to schedule your free foundation evaluation today!


Brian Dalinghaus

Brian is one of the Co-Founders of Dalinghaus Construction. He has been in the foundation repair industry since 2005. During his career, he has been associated with helping over 4,000 homes and structures throughout California and Arizona.

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