Crawl Space Supports
NSquare specializes in commercial foundation solutions, including the installation of systems designed to provide supplemental support in crawl space applications. Whether you are having crawl space issues with a project currently under construction or are an existing business experiencing crawl space problems, our team of experts can diagnose the problem and determine a solution that is tailored to your specific needs, both structural and budgetary.
Regardless of the issue, you should understand crawl space problems don’t get better with time, and they’ll never be less expensive to fix than they are today.
What Causes Crawl Space Problems
When the floor above a crawl space sags, it’s typically due to one or more of the following reasons:
Existing columns are spaced too far apart.
When a crawl space is built, block or brick (sometimes wood) columns are located throughout the crawl space to support the weight of the structure above. If those columns are spaced too far apart, the beam can become overloaded and sag between the columns. The girder then sags with it, as does the floor above.
Floor joists and girders have weakened.
Because crawl spaces are often open to and unprotected from the elements, excess moisture and humidity can cause problems. When wood is exposed to moisture and humidity, it can rot, become moldy and weaken. When this happens, girders and floor joists are no longer able to support the weight above, and the floor above the crawl space becomes bouncy, soft and may begin to sag.
Existing columns have settled.
Weak soil can cause the existing columns in the crawl space to sink or settle, often creating a gap between the top of the column and the bottom of the girder it was supporting. Once the column settles, the girder sags and the floors above sag in a chain reaction.
The “Smart” Solution
The Supportworks SmartJack® System is designed specifically for use as supplemental support in a crawl space, to shore up sagging joists and beams and to be used in conjunction with the existing column. The galvanized steel components and the cast aluminum footing work in tandem with a cube of compacted engineered fill rock that absorbs and spreads the load to the surrounding soil and over a larger area. This leaves a sturdy, permanent fix that actually addresses the issues that caused the floors above the crawl space to sag in the first place.
The SmartJack® may also be used as supplemental column support where an existing column and pier foundation has settled.
The allowable system capacity of the assembled SmartJack® steel components is 30 kips (30,000 pounds). Axial compression tests completed at an independent laboratory on the assembled SmartJack® system, with and without a pre-cast concrete footing, resulted in ultimate values between 56 kips and 90 kips.
While the rigidity and strength of the SmartJack® components benefit installation and overall product stability, the allowable load applied to the SmartJack® system will nearly always be limited by the bearing capacity of the existing soil.
The well-compacted crushed stone or recycled concrete base is a proven method to increase support for the higher bearing pressure condition immediately below the concrete footing, and then to absorb and distribute lower pressures to the existing soils (see the section on “The Bulb of Influence,” below). Except in extreme soft conditions, allowable loads on the order of 10 to 15 kips are typically achievable without any future appreciable settlement.
Should settlement of the SmartJack® system occur, adjustments are made easily by extending the all-thread rod. The SmartJack® system is designed to support axial compression loads only. SmartJacks® should not be used in applications where the system is intended to resist lateral loads.
The tube steel used for the SmartJack® is manufactured with a triple-layer, in-line galvanized coating. This coating process consists of:
• A uniform hot-dip zinc galvanizing layer
• An intermediate conversion coating to inhibit the formation of white rust and enhance corrosion resistance;
• A clear organic top coating to further enhance appearance and durability. The inside of the pier tube also has a zinc-rich coating.
The remaining steel components of the SmartJack® come zinc-plated as standard in accordance with ASTM B633, “Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel.”
The Bulb of Influence
Though the manufacturing quality of the SmartJack® system components is extremely high, it is the engineering that really sets it apart from other crawl space support options.
Here’s how the science works: at a depth of twice the bearing width, bearing stresses dissipate to approximately ten percent of those at the bearing surface. The SmartJack® pre-cast concrete base and cast aluminum base are 12 inches wide. This is the bearing width. Two times 12 inches is 24 inches or two feet. So, at the bottom of the two-foot hole, the pressure that was being exerted at the structural footing base is reduced to only ten percent of what it was.
Even if the soil at the bottom of the excavated hole isn’t all that strong, you can be assured that the ‘Bulb of Significant Stress Influence’ has already been distributed within the compacted crushed stone or recycled concrete fill. This is what makes the SmartJack® system “smart,” because it reduces stress on the original soil by 90-percent. Any competing system that does not address these concerns is not a long-term solution.
The reason the bulb of influence is so important is that, unlike other solutions, the SmartJack® system addresses one of the fundamental issues that cause crawl space problems: poor soils. So, what causes the soil beneath a structure to no longer be able to support its weight?
Drying & Shrinking of Soil
• Drought — When dry periods extend for months or years, clay soil dries out and shrinks. As the amount of soil around the structure shrinks in size, it creates an empty space for it to settle into.
• Maturing Trees — Did you know that the root system of a tree is often two times the size of the tree canopy? This means a tree with branches that extend over a structure is likely to have roots that extend under it, drawing valuable moisture from the soil. What happens when the soil dries out? More voids form and more settlement occur.
Wetting and Softening of Soil
• Heavy Rains — As clay soil gets wet, it holds on to the water and becomes very soft. This soft soil can be weak, causing the structure to sink down into it. Much like your foot “squishes” into a muddy field, a structure’s footing will do the same.
Compression of Poorly Compacted Fill Soil
• A common practice when developing land involves removing soil from hilltops and placing it in valleys to create flat, buildable lots. When this fill soil is not compacted well, it will compress under the weight of a structure, causing settlement.
For these reasons, it is critical to choose a crawl space solution that not only shores up the structure’s joists and girders but also addresses the soil beneath it. This is why the SmartJack® system is designed to be installed in conjunction with the aforementioned bulb of influence.
Signs and Symptoms of Crawl Space Problems:
• Floors slope, sometimes creating a gap between the floor and interior walls.
• Cracks in interior walls and gaps around door frames occur, caused by a wall sinking along with the floor.
• Doors stick or have been ‘shaved down’ to allow closing.
• Gaps appear between existing columns and girders in the crawl space.
• You notice shimming between existing columns and girders in the crawl space (a sign of past repair attempts).
• The effects of moisture are evident: wood rot and deterioration of the floor joists in the crawl space.
If you notice one or more of the above symptoms, it could mean that your structure is experiencing crawl space issues that need to be addressed permanently. This can only be determined by someone trained in the diagnosis and treatment of crawl space problems. (See “Diagnosing the Problem,” below.)
Solutions to Avoid:
You may be tempted to turn to crawl space solutions that seem less expensive at first glance. However, these can often present more problems than they solve, instead of addressing your issues permanently. Common solutions include:
• The Process
Concrete footings are poured throughout the structure’s crawl space. After the concrete footings cure, concrete blocks are stacked on top of the footings, sometimes with mortar placed between the blocks. After the mortar cures, shims are placed between the uppermost concrete block and the girder. This may appear to be a good solution because concrete is a strong material, or because it is commonly offered by contractors, especially those who do not specialize in foundation repair.
• The Problems
Not only is this solution time consuming (long waits for concrete and mortar to cure), but it is also not adjustable. As the concrete columns later settle into the soil below, additional shims may need to be added. In other words, this is a fix that will need to be repeated, again and again. This is because the concrete columns themselves are not the main problem; the soils beneath them are. The bottom line is, this option doesn’t address the root problem.
Light-Duty Crawl Space Jacks
• The Process
A concrete block is laid on top of the soil and a light-duty crawl space jack is set into place. The light-duty jack post is then tightened to fit against the girder.
• The Problems
Light-duty crawl space supports were never intended to support the weight of live loads and load-bearing walls. They have adjustable top brackets designed only to tighten them up against the beam above, not to lift a floor. They are made of thin, unprotected or spray-painted steel that rusts, corrodes and weakens over time. Most importantly, these posts do nothing to address weak soils that can give way under their base, even when they are set on a concrete block or pad.
Diagnosing the Problem, Developing a Custom Solution
NSquare commercial design techs are trained to expertly diagnose crawl space problems. They use highly specialized equipment that allows them to develop a solution tailored to your structure’s unique needs. By the time the inspection is over, you’ll know exactly what caused the problem, exactly what it will take to fix it permanently and exactly how much it will cost to do so.
Once a solution has been customized for your application, we pick a date for the job. At that time, a highly trained crew of technicians will install the solution, leaving your structure fixed and protected for decades to come.
To arrange a free, no-obligation inspection, call (239) 206-1480.
Advantages of the SmartJack® System
• It’s the only solution to the underlying issue: problem soils under the structure.
• Engineered fill replaces the poor soils, supports and dissipates the column load, and is unaffected by changes in moisture.
• Heavy-duty, threaded rods are designed to lift the floor back to its original position.
• Once installed, the system provides immediate stabilization and lift.
• It's engineered to support large loads and is suitable for large homes and load-bearing wall construction.
• Installation is quick and can be done year-round.
• Made of zinc-plated and hot-dip galvanized steel to prevent rust and eliminate weakening from moisture, mold and wood rot.