CAUSES OF SETTLEMENT

1. CAUSES OF SETTLEMENT The causes of foundation settlement are rarely due to the design (or under-design) of the structure itself. More commonly, damage is caused as changes occur within the foundation soils that surround and support the structure. The following briefly describes a few of the more common causes of foundation settlement:

2. 1-Weak Bearing Soils • Some soils are simply not capable of supporting the weight or bearing pressure exerted by a building's foundation. As a result, the footings press or sink into the soft soils, similar in theory to how a person standing in the mud sinks into soft, wet clay. • In such cases, footings may be designed to spread the load over the weak soils, thereby reducing potential foundation settlement. However, the majority of settlement problems caused by weak bearing soils occur in residential construction, where the footings are designed based upon general guidelines and not site-specific soil information.

4. 2-Poor Compaction • Placement of fill soils is common practice in the development of both commercial and residential subdivisions. • In general, before a foundation can be constructed on a plot, hilltops are cut down and valleys are filled in order to create buildable lots. Properly placed and compacted fill soils can provide adequate support for foundations, and are sometimes brought in from off-site locations. • When fill soils are not adequately compacted, they can compress under a foundation load resulting in settlement of the structure.

6. 3-Changes in Moisture Content • Extreme changes in moisture content within foundation soils can result in damaging settlement. Excess moisture can saturate foundation soils, which often leads to softening or weakening of clays and silts. The reduced ability of the soil to support the load results in foundation settlement. Increased moisture within foundation soils is often a consequence of poor surface drainage around the structure, leaks in water lines or plumbing, or a raised groundwater table. • Soils with high clay contents also have a tendency to shrink with loss of moisture. As clay soils dry out, they shrink or contract, resulting in a general decrease in soil volume. • Therefore, settlement damage is often observed in a structure supported on dried-out soil. Drying of foundation soils is commonly caused by extensive drought-like conditions, maturing trees and vegetation and leaking subfloor heating, ventilation, and air conditioning (HVAC) systems.

8. 4-Maturing Trees and Vegetation • Maturing trees, bushes and other vegetation in close proximity to a home or building are a common cause of settlement. As trees and other vegetation mature, their demand for water also grows. • The root systems continually expand and can draw moisture from the soil beneath the foundation. Again, clay-rich soils shrink as they lose moisture, resulting in settlement of overlying structures. Many home and building owners often state that they did not have a settlement problem until decades after the structure was built. • This time frame coincides with the maturation and growth of the trees and vegetation. • Foundations closer to the surface are more often affected by soil dehydration due to tree roots than are deep, basement level foundations. As a general rule, the diameter of a tree's root system is at least as large as the tree's canopy.

10. 5-Soil Consolidation • Consolidation occurs when the weight of a structure or newly-placed fill soils compress lower, weak clayey soils. The applied load forces water out of the clay soils, allowing the individual soil particles to become more densely spaced. • Consolidation results in downward movement or settlement of overlying structures. Settlement caused by consolidation of foundation soils may take weeks, months, or years to be considered "complete." • As this occurs, the foundation will experience downward movement -- sometimes at an uneven rate. This leads to cracks and structural damage.

12. Foundation Underpinning and Piering There are two methods used to support sinking foundations: 1-Foundation Push Piers and 2-Foundation Helical Piers. Foundation Push Piers The Foundation SupportworksPush Pier System permanently stabilizes your home's foundation and offers the best opportunity to lift your home back to level without the expense and disruption of a full foundation replacement. If you've detected cracks, uneven floors, jamming doors or windows that stick, then you may be witnessing the signs of the settling foundation. Contact a local Foundation Supportworks expert to ensure that you utilize the easiest and least invasive means of repairing your settling foundation.

13. Foundation Supportworks Push Pier systems utilize high-strength steel pier sections that are hydraulically driven through heavy-duty steel foundation brackets to reach deep down to competent load-bearing strata. The piers have the ability to reach far below the problem soils and do not rely on friction for capacity. Used in both residential and commercial applications, pier installation can be completed year-round without the major disruption of other methods. Foundation Supportworks Push Piers effectively stabilize settling foundations and provide the best opportunity to lift your home back to a level position.

14. Push Pier Advantages: • Can be installed year-round • Piers reach greater depth than other options • Long life span – galvanized steel is resistant to corrosion • Does not require the use of invasive equipment • In most cases can lift foundation back to level position • Restores Property Value

15. Push Piers • Push pier systems are an easy, economical solution that will provide you with a long-lasting result. • Manufactured with industrial-strength, galvanized steel, Foundation Supportworks piers have a high resistance to corrosion with a 100+ design life in moderate soil conditions

16. Push Pier Installation Steps: Step 1: Footing is exposed and prepared for the bracket.

17. Step 2: Foundation Bracket is secured to the footing.

18. Step 3: Steel pier sections are hydraulically driven through the bracket to competent soil or bedrock.

19. Step 4: The weight of the home is transferred through the piers to load bearing strata. Home is lifted back tolevel if possible.

20. 2-Helical Pier Systems The helical pier systems offered by Foundation Supportworks can fix your failing foundation and restore the property value of your home. If you've noticed interior or exterior wall cracks, a leaning chimney, or gaps in window and door frames, you could have a serious foundation problem.

21. Foundation SupportworksHelical Pier Systems will permanently stabilize your home's foundation and provide you an opportunity to lift the structure back to a level position. Round-shaft helical piers have a high resistance to buckling and have the torsional strength to penetrate deep into competent soil unlike other square-shaft helical alternatives. Another benefit of helical piers is that they do not use the weight of the home as resistance during installation, so they can be used on both heavy and lightly loaded structures such as sinking stoops, decks, or sunrooms. • Helical piers are installed by mechanically "screwing" them into the soil using small construction equipment or handheld equipment. Once they reach the proper depth, heavy-duty steel brackets are installed under the footing.

22. Helical Piers Foundation Supportworks helical piers are able to efficiently stabilize distressed foundations by transferring the load of the structure from unstable soil, through the piers, to competent soil strata below. The Journal of Light Construction states that compared to rebuilding a concrete foundation, installing helical piers is much faster, usually taking at least a week or two less than the alternative.

23. Helical Pier Advantages: • Can be installed year-round • Round shaft has a high resistance to bending • Suitable for both heavy and light loads • Long life span – galvanized steel is resistant to corrosion • Doesn't rely on the weight of the structure for depth and capacity • In most cases can lift foundation back to level position • Restores Property Value

24. Helical Pier Installation Steps: Step 1: Footing is exposed and prepared for the bracket.

25. Step 2: Round-shaft helical piers are mechanically advanced into the soil

26. Step 3: Foundation Bracket is secured to the footing.

27. Step 4: The weight of the home is transferred through the piers to load bearing strata. Home is lifted back tolevel if possible.