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Fixing Sagging Floors With Crawl Space Support Jacks

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Installing structural support jacks in your foundation can assist in preventing future structural damage. However, it can be challenging if not impossible for the average homeowner to do it themselves. But for professionals with the right knowledge, it can be a straightforward process. Read to learn more about structural support jacks.

Joists vs Beams & Girders

We get questioned quite a bit about the distinction between a joist and a girder. So, here you go:

  • Joists: Floor joists are more undersized – usually from 2″ x6″ to 2″ x12″ – and designed in a parallel series on top of the rafters. Your home’s floor sits immediately atop the floor joists, which sit atop the rafters.
  • Girders/Beams: The beams in your crawl space usually range in size from 4″ x6″ to 6″ x 8″ – maintain the floor joists and run vertically to them. It is generally called a girder. But, in Midwestern and Eastern states, they are referred to as beams. So, those terms – beam vs. girder – will alter depending on the geographic region. In other words, two people might be discussing the same thing while using different words to describe it.

Obvious Signs of a Sagging Crawl Area

The most obvious signs of a sagging crawl space are cracks in internal walls, sloped floors, and basements that feel spongy if you walk on them. If your house possesses a crawl space and you notice any of these signs, contact HydroHelp911 and schedule an examination right away.

What makes beam, girder, and joist problems in a crawl space?

Over time, crawl spaces can begin to sag for several reasons, including too much water, incompetent support, and a deficiency of floor joists. So let’s take a glance at all in additional detail.

Problem soils – Beams, rafters, and joists support the floor beyond a crawl space. Nevertheless, when these beams, rafters, and posts are assembling in less than perfect soil – that is, soil that isn’t strong enough to accurately support the structure – you’re going to have problems.

Water invasion – Many foundation difficulties are caused by too much water, including basement problems. Holding water in a crawl space is a sign there’s excess water getting in from somewhere. If you recognize this, it’s time to call a sewerage contractor to fix the problem. After that, you can adjust your support posts using shims or by substituting the support posts with screw jacks.

Inadequate support – Sometimes, crawl spaces begin to sag simply because they didn’t accurately construct the floor system. That may not be visible when a house is new, and everything seems to be operating fine. However, over time it can point to problems. In this case, we can append support girders within the existing rafters and some added cement footings and support posts or screw jacks to cut down the span within the existing beams.

Lack of floor joists – Some floors are built using a plywood subfloor – over 4″ x6″ beams set four feet apart – instead of floor joists. Because these floors undergo a lack of support from underneath, they can get wet and start to dip near walls. We can fix this problem by supplementing floor joists or floor beams to maintain the existing floor rafters.

What is Jacking?

While some of us are interested in jacking up a complete house, whole with cribs, girders, timbers, and everything else you require to lift a place off the ground, several people among us feel the need to jack up a piece of the house to insert an extra tier or beam for renovations or to level an old, slanted floor.

First of all, lifting a complete house into the air is entirely out of the question for an amateur. There’s too much that can go wrong. If you don’t grasp what you’re doing, it’s dangerous for your house and very risky for everyone involved.

Jacking up the edge of the apartment is another story, but there’s still enough opportunity for you to create significant damage, not to mention the potential danger. For example, you might set out to jack up your house, and you’ll end up doing just that—jacking up your home.


Not surprisingly, an average hydraulic jack is no match for a house. Take your most muscular automotive jack out of the garage, and this jack will crumble below the weight of a home. More specifically, it will never even start to lift. Jacking a house typically is performed with screw jacks and a quantity of them. Hydraulic jacks are also employed. In any case, you would need at least 20-ton jacks, and 40-ton is better. You can lend heavy-duty jacks, but a rented hydraulic jack would be below the home for a very prolonged time, running up charges, so you’d be better off having them.


A house is created of thousands of items of lumber, nails, screws, wire, metal, masonry, and many other types of building elements. All of these substances are interlocked, similar to a jigsaw puzzle. Contrary to what you might presume, a house does not increase or lower like a giant box. Alternatively, a place extends or lowers more like a king-size mattress.

Imagine moving underneath a mattress and trying to elevate any portion of it by your fist. Most of the mattress rests stock-still, utterly unmoved by your efforts. Even areas of the mattress near your hand barely move. It is only the portion of the bed directly above your hands that rises. Same goes with a house.

Install one, two, or even five hydraulic or spiral jacks in a narrow range beneath the house, lift slowly, and the disappointment begins. First, you discover the housing protest with cracks as loud as rifle shots. Joists groan. Upstairs, cement and drywall damage and decay and fall. Yet below, there is a small sign of altitude.


If you intend to raise and shore any piece of your house from underneath in a basement or crawl space, have in mind that you will not influence more than a small portion. Even then, you will accomplish nothing more than following rotten timbers with new timbers or girders and maintaining the corresponding slant of the floors above.


As a generic rule, a home—including any part of a home—should be elevated no more than 1/8 inch per day. So if you plan to raise the house up 1 inch, it will take at least eight days. This slow pace gives all the related materials a chance to settle into the new position without falling apart. Presumably, the house began square, plumb, and level, and it slowly decided over time that it’s gotten used to the new site, as cockeyed as it may be. If you fall under the floor and commence raising it to its original elevation without giving the materials time to adjust, you’ll produce lots of damage.


Homes must be lifted utilizing the same supports that keep the house standing, such as the carrying beams and the load-bearing walls. Understanding where to place jacks, how many to use, and how to distribute the weight of each jackscrew is critical to a secured and successful house raising. Likewise, if you know home structures and which components carry the loads, jacking a house is, in some ways, the opposite of those forces, so standard structural rules don’t always apply. Understanding what to expect takes experience. Do you desire to cut your teeth in your own house?


Don’t let foundation concerns keep you up at night. Schedule a free consultation with HydroHelp911 today and let our team of experts inspect your home for any signs of damage. We understand that foundation problems can be scary, but with our professional assessment and expert repairs you can gain peace of mind knowing your home is in capable hands.

Frequently Asked Questions:


Each circumstance is different. Our specialists are trained to diagnose crawl space problems. In addition, we use highly specialized tools that allow them to develop a solution tailored to your home’s requirements.


Usually, the pier blocks in a sagging crawl space are reliable and don’t need to be replaced. However, since the problem is always with the posts or the screw jacks, we can remove and restore them to lift the floor.

We use screw jacks to repair a sagging crawl space because they’re versatile. They’re quick to install, able to maintain the floor’s weight and can be adjusted later if needed.

Our expert team will fix your problem quickly and efficiently. We offer free estimates, so there are no surprises when you receive your bill.

Schedule your foundation repairs today by calling us at 704-741-9737.

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