Sagging or uneven floors indicate foundation problems. Over time, structural issues can worsen, affecting everything from door and window alignment to overall safety and livability. Simple but tried-and-true solutions like screw jacks can lift and support your home permanently.
In this guide, learn what causes sagging floors and how to fix them. Leveling a house helps maintain its integrity, and timely intervention with foundation jacks prevents costly repairs down the road.
What Causes Sagging Floors?
Crawl spaces and basements can face issues that lead to weakened joists or deteriorated pier and beam systems. There are a number of reasons this happens:
- Damaged/rotten support posts
- Beam spacing/insufficient support
- Poorly compacted soil/frost line
- Heavy load from above
- Dismantling from below
Basically, if the sub-area has deteriorated beams, they need to be beefed up. Or, if the span between piers is too large or the beam is not large enough to support the load across that distance. So, you have to put something in the middle to make up for the fact that the beam is not large enough to support the span.
A Deeper Dive into Causes
Soil and Ground Types
There are different types of soil, and some cause the foundation to settle. So basically, whatever is supporting the beams has dropped. Since the ground has sunk, there’s a new settling point underneath the beams, so you need to raise that back up.
Troy Frost, Vice President of Sales, explains that in cold areas, many issues stem from where you have to build as close to or below the frost line. Frost heave can cause structural damage because of the freezing and thawing of the soil. Basically, the heave and ho of the ground underneath the foundation create pressure. This is one reason why locations in sub-freezing temperatures end up with cracks or sagging floors.
Overloaded Joists or Poor Beam Spacing
Excess weight from renovations, improper construction, or aging materials can stress floor joists beyond their capacity. If there are too few piers or beams are spaced too far apart for the load, everything becomes stressed and overloaded. Additionally, weight from above or dismantling from below can cause issues.
Brian Park, Director of Sales and Business Development in the Central US, shares that “in some of the newer homes or remodels, if somebody put in tile, granite, or marble…or they put in a huge island or large appliances, sometimes this can have an effect.” For example, a fireplace, kitchen island with a heavy countertop, or new bathroom renovation can overload foundations because what was adequate when the home was built is no longer adequate, as you've added a lot of weight on top of that space.
Moisture Damage
Moisture causes problems like rotting or mold in places like crawl spaces. Wood and beams can rot and deteriorate, but another culprit is that poor drainage and leaks can cause the piers to sink.
An easy and reliable solution for sagging floors is to use screw jacks for houses. They are a key tool for lifting and leveling. Some are made of steel, while others use steel and lumber. Likewise, some are made for supporting only, and others are designed to both lift and support. But first, you want to accurately diagnose the problem.
What to Look For: Diagnosing the Problem
A thorough assessment will help determine if you can fix the problem yourself or if you should call an engineer.
Conduct a Visual Inspection
Start by carefully examining your home for signs of structural distress, like:
- Sagging, bouncy, or creaky floors or noticeable dips when walking across a room.
- Cracks in walls or ceilings, especially near doorways and windows.
- Windows and doors that become difficult to open or don’t close properly.
- Foundation cracks, shifting, or visible separation from the structure.
These indicators suggest foundation problems that require further investigation. While minor leveling issues can be handled with foundation jacks, significant structural issues require expert evaluation. Call an engineer if:
- You notice large or widening foundation cracks.
- The home has more than one story.
- You have severe floor sloping or rapid deterioration.
- It’s a commercial building.
- You see persistent moisture issues despite drainage improvements.
How to Fix Sagging Floors
There are many ways to tackle the issue, but make sure to consider longevity and adjustability. You may want a solution that allows you to easily make adjustments to the supports, or have the flexibility of additional lifting height and power. Here are some common ways to fix sagging floors:
- Shimming: Shimming or re-shimming involves inserting shims made of metal or wood to help level beams.
- Underpinning: Long poles driven or screwed directly into the ground to reinforce the existing foundation.
- Sistering Joists: Connecting new pieces of wood to the old, failing wood helps support the weaker joists.
- Metal Bridging: Adding metal bridging or “x-bracing” helps joists share the weight.
- Blocking: Blocking can mean reinforcing joists by placing wood blocks perpendicular to joists (like where x-bracing might go), but can also be blocks mortared together (often reinforced with rebar) and stacked in place of a pier.
You can just go in and lay new wood to replace the old piers, but if your floors are sagging, you’ll want an option to lift and support. This calls for reinforcements like screw jacks.
Optimal Solution: Screw Jacks
Screw jacks use steel or a combination of steel and wood to support the beams under your house. They are easy to install and can be used as a temporary or permanent solution.
With screw jacks that lift and support, you get a 2-in-1 solution. Ellis Manufacturing screw jacks have a locking mechanism and high load capacities that are backed by a two and a half times safety factor.
- Load capacity: Our load capacity is listed at maximum height, unlike our competitors. So other jacks list a load capacity that’s at minimum height, meaning the jack gets weaker as you lift it up from that minimum height. If another jack says it will support 12,000 lbs, and ours says it will support 12,000 lbs, ours is 12,000 at the weakest point. Whereas their jack might be 12,000 at its strongest point, and then it gets weaker from there. Ellis Manufacturing offers capacities up to 80,000 lbs and are based on real-world tests.
- Failure point: Our jacks have a two-and-a-half times safety factor built into our load capacities. That means, for example, if our jack supports 20,000 lbs, then the failure point of that jack is 50,000 pounds because it's two and a half times what is listed as the safe load capacity. Whereas with a lot of other jacks, they just list the load capacity. They don't say whether there's a safety factor built in or if that's the failure point of the jack.
- Adjustability: Ellis Manufacturing screw jacks offer adjustments from a few inches to just over two feet of vertical travel. And, you can make these adjustments as often as you need them. Plus, our jacks range in size—everything from 3 inches off the ground to 14 feet 6 inches off the ground. Make sure to determine the necessary lifting height to avoid exceeding the jack’s limits, which could lead to device damage or safety hazards.
Screw Jack Types
Selecting the right screw jack for house leveling is essential to ensuring a safe and effective installation. Below, we break down the different types of Ellis Manufacturing jacks, some of which feature a patented thrust bearing designed to reduce friction and provide superior lifting capability.
Steel Lifting Shores
Ellis Manufacturing Steel Shores are heavy-duty floor jacks capable of supporting up to 80,000 lbs, making them a safe and reliable choice for house leveling and structural support. These jacks are designed for durability and long-term use, featuring:
- Patented thrust bearings that minimize friction, making adjustments easier under load.
- A fully assembled, one-piece design that prevents components from separating.
- A built-in safety lock ensures secure, long-term shoring applications.
Screw Jacks Using Lumber
For those preferring a versatile and dependable option, Ellis Manufacturing offers screw jacks using lumber. These jacks are designed to fit nominal 4x4” and 6x6” job cut lumber posts and are ideal for residential, commercial, and emergency shoring scenarios.
These screw jacks have a box end that's welded to the top of it, and a screw that gives it adjustment on the bottom with a base plate below that. Most often just called “screw jacks,” you can use them vertically to make any size shore with 6” of height adjustment. Basically, you slide a piece of lumber down into the box end that's on the top of it.
- 4x4” jacks support up to 15,000 lbs, making them suitable for most residential applications.
- 6x6” jacks hold up to 30,000 lbs, making them a great choice for commercial concrete construction and structural repair.
Standard Steel Shores
The light-duty steel shores are perfect for simple foundation support projects requiring dependability without the thrust bearing technology. With seven different adjustable heights, these are designed for versatility and boast a safe load capacity ranging from 3,000 to 20,000 lbs, making them suitable for supporting foundations or reinforcing beams in crawl spaces and attics.
Choose from our various options here →Mini Screw Jack
For house leveling projects requiring a compact and powerful solution, the Ellis Manufacturing Mini Jack is a short support jack available in two sizes: the MJ-3 with a minimum height of 6.5 inches and the MJ-6 with a minimum height of 9.5 inches. Both models offer a robust, safe load capacity of 15,000 lbs, making them perfect for where space is limited.
Mini Jack Video: Learn how to use it →Stealth Lifting Shore
With 11 height options and a max width of 3.5”, these also have lifting capabilities made 10x easier with our patented thrust bearing nut assembly. Designed to be both strong and narrow, Stealth Jacks can be fit and sealed inside a standard 2x4-framed wall and range in support from 3,000 to 20,000 lbs.
Select a size here →Need help selecting the right jack for your sagging floors? Call us at (800) 654-8311 for advice.
Important Considerations in Choosing a Jack
- Lifting vs. Supporting: If you need to lift and support, a Steel Lifting Shore is the best option. If you only need to reinforce the structure, a lumber shore (Screw Jack) or Standard Light Duty Steel Shore is a more adaptable choice. If you have access to job cut lumber, our 4x4 or 6x6 screw jacks are a great versatile option.
- Footing: Knowing how thick the concrete is under houses is tricky, and some have none. Although you can use gravel, it’s porous, and you may have to do more adjusting than if you pour concrete to make a footer.
Remember to pay attention to building codes because you may, for example, be required to pour concrete. One more safety note: lifting and supporting with an Ellis Manufacturing screw jack is a convenient 2-in-1 option but you still need to take your time. Always lift gradually, and make sure to address underlying issues like moisture.
Accessories for Enhanced Support
- Joist Holders, Purlin Splicers, U-Heads: These secure nominal 4x4” or 6x6” posts to joists and ensure strong purlin connections. U-heads fit the steel shores by removing the top, putting a u-head on, and then sliding the beam into it. Ellis Manufacturing offers multiple-sized joist holders, including single, double, triple, and quadruple 2x4s.
- Base Plate Extensions: Base plates help spread the load to try to avoid cracking or compromising. We also offer top plates for increased stability. These should be placed on an adequate footer.
- Hydraulic Bottle Jacks: If you need more power, our hydraulic bottle jacks are efficient and powerful (up to 20 tons). This is a great complement to the Ellis screw jacks if you need additional lifting power.
Known for durability and being the trusted leader for almost 75 years, our screw jacks exceed industry standards, ensure easy weight adjustments, and provide long-term reliability to fix sagging floors.
How to Use: Step-By-Step
Make sure to take all the necessary safety precautions prior to starting and consult with a structural engineer if you’re unsure about load, spacing, footing, etc.
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Inspection
Make sure everything is plumb and level, reposition if needed, and tighten the safety lock screw with an allen wrench. Ellis Manufacturing screw jacks can be used as permanent or temporary solutions.
FAQs
Do I need a heavy-duty or a light-duty shore?
Always consult with a professional if you’re unsure, but a good rule of thumb is that if you have to lift (vs. just support) sagging beams, have more than one story, or are dealing with a commercial building, you will need heavy duty screw jacks.
Do I need a permit?
If you’re unsure about permitting, check local laws, call the city planning committee, or consult with an engineer.
Which of the two light-duty shores do I need?
Are you lifting a sagging floor or just supporting weight under your home? If you want to keep everything in the same position, the light-duty standard steel shore should work for your needs. Call us to help differentiate.
If you need lifting because some foundation has shifted, but then afterwards to support your home, you’ll want a lifting steel shore. That being said, it still depends on how much weight you’re supporting. For example, a three-story home is most likely going to require a heavy-duty shore. For a simple or lighter-weight project, a light-duty lifting shore will work.
What if the jack won’t turn or adjust easily?
Check for dirt, rust, or debris in the screw mechanism. Lightly apply oil to lubricate moving parts or in the small hole in the nut to lubricate the bearings. Lastly, ensure the jack is not overloaded beyond its weight capacity.
Industrial Grade Solutions
Choosing the right house jack is more than just a purchase—it’s an investment in your home’s safety and stability. For almost 75 years, our exceptional customer service and high-quality product line have made us the industry standard.
The Ellis Shore has been a staple of the concrete framing industry since its inception.
- Luke Holmboe, Vice President of Marketing
From safety rescue to DIYers, we want to set you up for success. Check out our YouTube channel for information videos on our unrivaled high-performance lifting solutions.
Order online, text us at (405) 528-4671 for quick questions, or call us to discuss your project or any custom solutions you need at (800) 654-8311.
Disclaimer: The information provided in these articles is for general informational purposes only and is not intended as a substitute for professional engineering advice. Every project has unique requirements and complexities. Therefore, it is essential to consult with a qualified professional engineer to guide you through the specific nuances of your individual project and ensure its safety and compliance. These articles do not offer engineering guidance.