Decoding Brickwork: When Stair-Step Cracks Indicate a Structural Emergency

It is natural to feel a sudden knot of anxiety when you walk outside your home and notice a jagged, zig-zagging fissure creeping up your exterior brickwork. For many homeowners, a home represents their most significant financial asset, and visible masonry damage can immediately trigger fears of catastrophic structural failure and exorbitant repair bills. However, understanding the geotechnical mechanics beneath your home is the first step toward reclaiming your peace of mind.

While masonry cracks can sometimes be attributed to normal, uniform settling, the distinct pattern of stair-step cracks running through the mortar joints is a well-documented scientific indicator of uneven foundation movement. This report bridges the gap between complex geotechnical engineering and accessible homeowner education. By examining the underlying soil dynamics—specifically the behavior of expansive clay soils as measured by the United States Department of Agriculture (USDA)—we can decode what your brickwork is trying to tell you.

Key Points on Stair-Step Masonry Cracks:

• Scientific consensus suggests that stair-step cracks following mortar joints are a primary visual indicator of differential (uneven) settlement rather than uniform settling [1, 2].
• The evidence leans toward expansive clay soils being the primary culprit; these soils can exert up to 5,500 pounds per square foot (PSF) of uplift pressure on a foundation [3, 4].
• Research indicates that over 50% of homes in the United States are constructed on expansive, volatile soils [5, 6].
• Industry data projects that structural repair via underpinning (using push or helical piers) is highly effective, though it represents a significant investment.

Understanding the Limitations of Algorithmic Estimates

Disclaimer: The information provided in this report, as well as the algorithmic foundation repair estimates generated by our website, are designed to serve as a first-step market estimate. We utilize aggregated USDA soil data and US Census construction cost data to provide baseline projections. We DO NOT provide official engineering documents for bank loans, insurance claims, or municipal grants. Our calculator is an educational tool and does not constitute engineering or legal advice. ONLY a licensed structural engineer (reached via the contact panel on our site) can provide official, legally binding diagnostics, stamped engineering reports, and final repair quotes.

TL;DR (Key Takeaways)

For homeowners seeking immediate clarity, here are the core takeaways regarding stair-step cracks in exterior brick:

• The Path of Least Resistance: Stair-step cracks occur because rigid brick mortar cannot withstand the shear forces generated when one part of your home sinks deeper into the soil than another [7].
• The Soil Shrink-Swell Cycle: Heavy clay soils act like a sponge. They expand violently when wet and shrink when dry, creating an unstable, shifting base beneath your foundation [8].
• The 1/8-Inch Warning Rule: Hairline cracks may be cosmetic, but cracks wider than 1/8 inch—especially those that are wider at the top than at the bottom—are strong indicators of active structural failure [9, 10].
• Complementary Symptoms: Stair-step cracks rarely act alone. They are often accompanied by sticking doors, sloping floors, and interior drywall cracks [11, 12].
• Professional Remediation is Permanent: Patching mortar is a cosmetic band-aid. True repair requires underpinning the foundation with steel helical or push piers driven into deep, load-bearing bedrock [13].

The Geotechnical Science of Soil: Why Your Brick Foundation is Under Attack

To understand why your exterior brick is cracking in a distinct, stair-step pattern, we must look below the surface. The stability of any structure is entirely dependent on the bearing capacity and volumetric stability of the soil upon which it rests [14].

The Threat of Expansive Clay Soils

According to the American Society of Civil Engineers (ASCE), roughly one-quarter of all homes in the U.S. sustain damage caused by expansive soils, resulting in billions of dollars in structural damage annually—more than floods, hurricanes, tornadoes, and earthquakes combined [15, 16]. Furthermore, research from the USDA and academic institutions indicates that up to 50% of households in the United States are constructed over these highly reactive soils [5, 6].

Expansive soil contains high concentrations of hydrophilic (water-absorbing) clay minerals, such as smectite and montmorillonite [17, 18]. These microscopic clay particles possess a negative electrical charge and a massive surface area, allowing them to attract and bind tightly to water molecules [19].

USDA Shrink-Swell Capacity and the COLE Index

The United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) measures the volatility of these soils using the Coefficient of Linear Extensibility (COLE) [17].

• Low Shrink-Swell Potential: COLE < 0.03
• Moderate Shrink-Swell Potential: COLE 0.03 - 0.06
• High to Severe Shrink-Swell Potential: COLE > 0.06

If the soil beneath your home has a COLE value greater than 0.06, it is officially classified as capable of causing structural damage [17]. A COLE value of 0.06 indicates that 100 inches of dry soil will expand by 6 inches when saturated with water [17]. When this expansion occurs, wet clay soil can weigh over 100 pounds per cubic foot and exert an astonishing 5,500 pounds per square foot (PSF) of upward hydraulic pressure against your foundation [4, 19]. This pressure is more than enough to bend concrete slabs, heave footings, and crack rigid exterior brick masonry [4, 20].

The Shrink-Swell Cycle

When the climate shifts from wet to dry—such as during a summer drought—the clay soil undergoes rapid desiccation (drying). As the water evaporates, the soil loses volume, shrinks, and literally pulls away from your foundation footings [4]. This leaves massive underground voids. Deprived of the soil support it was designed to rest upon, the massive weight of your home’s foundation sags into these empty voids [4]. This endless, cyclic heaving and sinking fatigues the structural components of your home until the concrete and masonry finally snap [21].

Understanding Differential Settlement: The Root Cause of Stair-Step Cracks

Not all foundation settlement is disastrous. Ongoing, minor building settlement is relatively common, particularly in the first few years after construction [22, 23]. However, the type of settlement dictates whether your brickwork survives intact.

Uniform Settlement vs. Differential Settlement

Uniform Settlement occurs when the entire foundation of a home sinks into the earth at an equal, constant rate [22, 24]. Because the entire structure is moving together, the framing and masonry maintain their alignment. Consequently, uniform settlement rarely results in significant cracking or structural damage [22, 24].

Differential Settlement, on the other hand, is the uneven sinking of a foundation. It happens when one section of your home settles at a faster or slower rate than the rest of the building [9, 24].

If the right side of your house drops by two inches while the left side remains stationary, the rigid materials connecting the two sides—specifically, your wood framing, concrete foundation walls, and exterior brick veneer—are subjected to extreme shear and tensile forces. Because brick and mortar are highly rigid and possess very little tensile flexibility, they cannot stretch to accommodate this twisted geometry [25]. They break.

What Triggers Differential Settlement?

While expansive clay soil is the primary medium for this movement, specific environmental triggers initiate the uneven settling:

1. Poor Drainage and Hydrostatic Pressure: If gutters are clogged, or if the grading of your yard slopes toward the house rather than away from it, water will pool against one side of the foundation [26, 27]. This isolated saturation causes the clay on that side of the house to swell massively, lifting that wall, while the dry side remains static.
2. Tree Root Desiccation: Large, mature trees planted too close to the home possess massive root systems that “drink” hundreds of gallons of water from the soil [28, 29]. During a drought, roots will pull moisture specifically from the soil directly under your foundation, creating localized voids that cause differential settlement [29].
3. Poorly Compacted Fill Soil: If the soil was not adequately artificially compacted by the builders before pouring the foundation, the sheer weight of the house will eventually compress the loose dirt unevenly [14, 30].
4. Underground Erosion: A broken plumbing line, an underground spring, or improperly routed downspouts can slowly wash away loose soil particles from beneath a footing, creating empty sinkholes into which the foundation collapses [1, 28].

Curious about the soil composition and historical shrink-swell data under your specific ZIP code? Use our local foundation calculator to generate a baseline assessment, or use the service contact panel on this page to consult a local, licensed professional.

Identifying Stair-Step Cracks: Cosmetic Flaw or Structural Emergency?

Brick masonry walls are essentially composed of two materials: the fired clay bricks themselves, and the mortar used to bind them. Understanding how these materials interact under stress is the key to decoding foundation damage.

The Anatomy of the Stair-Step Crack

When differential settlement forces one side of a brick wall to drop, the wall attempts to bend. Because masonry cannot bend, the energy searches for the weakest point to release the stress. Mortar is inherently weaker and more brittle than the fired brick it holds together [1, 7].

Therefore, the crack travels along the path of least resistance: up a vertical mortar joint, horizontally across the top of a brick, and up the next vertical joint, repeating this pattern [2, 23]. This creates a distinct, zig-zagging “stair-step” visual pattern [26].

These cracks are most commonly found:

• At the outside corners of the home, where intersecting walls amplify stress [25].
• Emanating from the corners of window frames and exterior doors, which are natural structural weak points [19, 23].
• Along the exterior face of basement block walls [23].

When to Worry: The Visual Diagnostics

Not every tiny fracture in a mortar joint demands a $20,000 repair. Superficial hairline cracks (less than 1/16th of an inch) can occasionally result from minor thermal expansion and contraction of the brick veneer in direct sunlight [2, 31].

However, stair-step cracks elevate to a structural emergency when they display the following characteristics:

The Accompanying Symptoms of Settlement

Differential settlement rarely limits its damage to the exterior brick. If your home is shifting, you will likely notice internal symptoms as well. If you observe stair-step cracks outside, immediately check the interior of your home for:

• Doors and windows that suddenly stick, bind, or fail to latch [11, 22].
• Cracks in the drywall, particularly radiating at 45-degree angles from the upper corners of doorframes [1, 22].
• Floors that slope, sag, or feel “bouncy” [22].
• Baseboards or crown molding separating from the wall or ceiling [19].
• Gaps forming between the exterior brick veneer and the window frames or chimney [11, 12].

The Financial Landscape: Foundation Repair Costs (2025 – 2026 Projections)

CRITICAL YMYL DISCLAIMER: The following cost estimates are aggregated market averages based on 2025 and projected 2026 data. They are provided for educational and budgetary purposes only. Our algorithmic calculator provides a “first-step market estimate.” These figures are NOT financial guarantees, and this tool does NOT generate official engineering documents required for bank loans, real estate disclosures, or insurance underwriting. ONLY a licensed structural engineer can provide an exact, legally binding repair quote tailored to your home’s specific geotechnical needs.

If your exterior brick is exhibiting severe stair-step cracks, patching the mortar (a process called “tuckpointing”) will not solve the problem [13]. If the soil is moving, the new mortar will simply crack again in a matter of months. Permanent remediation requires stabilizing the foundation beneath the soil.

According to national cost data and 2026 industry projections, the average foundation repair project costs roughly $5,000 to $5,100, though costs range widely from $2,200 for minor stabilization to well over $30,000 for severe structural failure [32, 33].

Underpinning: The Gold Standard for Differential Settlement

To permanently stop differential settlement, structural engineers use a method called “underpinning.” This involves driving heavy-duty steel piers deep into the earth until they reach stable, load-bearing bedrock or dense geological strata that is entirely unaffected by surface moisture changes [34, 35]. Once the piers are anchored in bedrock, hydraulic jacks are used to lift the foundation back to its original, level elevation, instantly closing the stair-step cracks in the brickwork [8, 13].

There are two primary types of piers utilized in the industry:

1. Steel Push Piers

Push piers are hollow steel tubes driven vertically into the ground using the actual weight of the house as resistance [33]. They are ideal for heavy, multi-story masonry homes where deep bedrock needs to be reached [33].

• Load Capacity: 40 to 70 tons per pier [33].
• Cost Estimate: $1,500 to $2,500 per pier [33, 36].

2. Helical Piers

Helical piers (also known as screw piles) feature spiral, screw-like plates welded to the steel shaft [36]. They are mechanically rotated (screwed) deep into the ground using hydraulic torque motors [36]. Helical piers do not rely on the weight of the house for installation, making them perfect for lighter structures, retaining walls, or porches [37].

• Load Capacity: 15 to 50 tons per pier [33].
• Cost Estimate (2025 - 2026 Projections): $2,000 to $4,000 per pier [35, 38]. Industry projections for 2026 confirm that due to steel costs, helical piers will consistently average $1,500 to $4,000 installed, with a typical $3,000 median [35].

Breakdown of Average Repair Scenarios

Are you trying to budget for a potential structural repair? Utilize our algorithmic foundation repair calculator to get an initial market estimate based on the linear footage of your home. Remember, to secure an official quote, use our platform to connect directly with a licensed structural engineer in your area.

Professional Remediation: Beyond the Piers

While underpinning is the mechanical solution to lift a home, a holistic repair plan engineered by a professional will also address the geotechnical root cause: water management.

Because stair-step cracks are ultimately caused by the uneven expansion and contraction of clay soils, controlling the moisture around your foundation is critical to protecting your investment after the piers are installed.

1. Correcting Grading: The soil adjacent to your foundation should slope downward, dropping at least 6 inches over the first 10 feet (a 2% to 5% grade) to ensure rainwater flows away from the masonry [1, 19].
2. Downspout Extensions: Since improper drainage causes 85% of basement water issues, an engineer will strongly recommend extending all roof downspouts 4 to 10 feet away from the foundation [1, 7].
3. Subsurface Drainage (French Drains): In areas with severe hydrostatic pressure, installing a perimeter French drain and a heavy-duty sump pump system ensures that underground water is aggressively routed away from the expansive clay surrounding your footings [1, 26].
4. Vegetation Management: Large trees should ideally be kept at least 15 feet away from the foundation to prevent their root systems from desiccating the clay soil and triggering further differential settlement [28].

Frequently Asked Questions

Are stair-step cracks in exterior brick always a structural emergency?

Not always, but they are a definitive warning sign that requires professional monitoring. Minor stair-step cracks (less than 1/16 inch wide) can sometimes result from initial, minor settlement in a new home and may remain stable for decades [2, 23]. However, if the cracks are wider than 1/8 inch, are actively growing, are wider at the top than the bottom, or are accompanied by interior drywall damage and sticking doors, they indicate active differential settlement [9, 10]. In these cases, it is a structural emergency that requires immediate assessment by a licensed engineer to prevent catastrophic failure [2, 10].

Can I just repoint the mortar to fix a stair-step crack?

No. Repointing (or tuckpointing) the mortar is purely a cosmetic fix [13, 23]. Stair-step cracks are a symptom of a much larger geotechnical problem: the soil beneath your foundation is shifting [1]. If you patch the mortar without stabilizing the foundation, the underlying differential settlement will continue, and the massive shear forces will simply crack the new mortar within a few months. Foundation repair via underpinning must be completed before cosmetic masonry repairs are attempted [41].

Does homeowners insurance cover stair step cracks in exterior brick foundation repair?

In the vast majority of cases, standard homeowners insurance does not cover foundation repair required due to earth movement, differential settlement, or expansive soil damage [18]. Insurance typically covers sudden, accidental damage (such as a fire, a fallen tree, or an abruptly burst plumbing pipe). Because soil expansion, soil erosion, and subsequent foundation cracking are considered gradual wear-and-tear or maintenance issues, insurance companies routinely deny these claims. Always consult your specific policy, but be prepared to finance foundation underpinning out of pocket.

What is the difference between push piers and helical piers for brick foundation repair?

Both are structural underpinning devices made of galvanized steel, but they are installed differently and serve slightly different purposes. Push piers are smooth steel tubes driven hydraulically into the ground using the sheer weight of your house as the resistance force [33]. They are ideal for heavy structures (like two-story brick homes) and can be driven extremely deep. Helical piers feature screw-like plates and are mechanically drilled into the earth using a torque motor, meaning they do not rely on the building’s weight for installation [36, 37]. This makes helical piers excellent for lighter structures, settling porches, or homes where the load-bearing soil is relatively shallow [33, 36].

How fast do stair-step cracks progress?

The progression rate of stair-step cracks is entirely dependent on the volatility of the soil and local weather patterns. During a severe, prolonged drought, expansive clay soil can shrink rapidly, causing a hairline crack to widen to half an inch in a matter of months [19]. Conversely, if the moisture levels in the soil remain relatively stable, the crack may barely change over a period of years [4, 12]. Because progression is unpredictable, it is vital to contact a licensed structural engineer for an evaluation as soon as the cracks are discovered.

Citations and Sources

1. [9] Tar Heel Basement Systems. “Differential Settlement.” https://www.tarheelbasementsystems.com/resources/foundation-repair/differential-settlement/
2. [30] Groundworks. “Differential Settlement Glossary.” https://www.groundworks.com/glossary/differential-settlement/
3. [11] All County Waterproofing. “What Expansive Clay Soil is Doing to Your Foundation.” https://allcountywaterproofing.com/2025/07/15/what-expansive-clay-soil-is-doing-to-your-foundation/
4. [22] Vertex Engineering. “Differential Settlement in Buildings.” https://vertexeng.com/insights/differential-settlement-in-buildings/
5. [14] Dalinghaus Construction. “How to Prevent Foundation Problems When There is Clay Soil.” https://www.dalinghausconstruction.com/blog/how-to-prevent-foundation-problems-when-there-is-clay-soil/
6. [17] Wikipedia. “Shrink–Swell Capacity.” https://en.wikipedia.org/wiki/Shrink%E2%80%93swell_capacity
7. [15] USDA NRCS. “Understanding Soil Risks and Hazards.” https://www.nrcs.usda.gov/sites/default/files/2023-01/Understanding-Soil-Risks-and-Hazards.pdf
8. [18] Texas Inspector. “Damage to Foundations From Expansive Soils.” https://www.texasinspector.com/files/DAMAGE-TO-FOUNDATIONS-FROM-EXPANSIVE-SOILS.pdf
9. [12] Geo-Institute. “Living With Shrink-Swell Soils.” https://www.geoinstitute.org/sites/default/files/inline-files/LivingWithShrinkSwellSoils.pdf
10. [42] USDA NRCS. “Soil Survey Manual - Chapter 8.” https://www.nrcs.usda.gov/sites/default/files/2022-09/SSM-ch8.pdf
11. [31] Carolina Foundation Solutions. “Foundation Cracks.” https://www.carolinafoundationsolutions.com/blog/foundation-cracks/
12. [13] TFS – The Foundation Specialists. “Stair Step Foundation Cracks in Brick.” https://thefoundationspecialists.com/blog/stair-step-foundation-cracks-in-brick/
13. [7] Forever Foundation Repair. “Understanding Stair-Step Cracks: Causes and Solutions.” https://www.foreverfoundationrepair.com/understanding-stair-step-cracks-causes-and-solutions/
14. [1] The Basement Doctor. “Stair Step Cracks in Brick Walls.” https://www.mybasementdoctor.com/blog/stair-step-cracks-in-brick-walls/
15. [23] All County Waterproofing. “Stair Step Cracks in Brick and Block: When It’s Cosmetic Vs Structural.” https://allcountywaterproofing.com/2025/12/16/stair-step-cracks-in-brick-and-block-when-its-cosmetic-vs-when-its-structural/
16. [41] Dalinghaus Construction. “When to Worry About Cracks in Brick.” https://www.dalinghausconstruction.com/blog/when-to-worry-about-cracks-in-brick/
17. [26] Bay Crawl Space. “Stair Step Cracks in Walls: What They Mean and When to Worry.” https://www.baycrawlspace.com/stair-step-cracks-in-walls-what-they-mean-and-when-to-worry/
18. [27] TFS – The Foundation Specialists. “Stair Step Foundation Cracks in Brick.” https://thefoundationspecialists.com/blog/stair-step-foundataion-cracks-in-brick/
19. [32] Modernize. “Foundation Repair Cost Guide.” https://modernize.com/foundations/repair-cost
20. [33] Best Amarillo Foundation Repair. “Foundation Repair Cost Amarillo TX: 2025 Complete Guide.” https://www.bestamarillofoundationrepair.com/foundation-repair-cost-amarillo/
21. [34] Regional Waterproofing. “Foundation Repair Cost Guide 2025.” https://regionalwaterproofing.com/blog/foundation-repair-cost-guide-2025/
22. [38] HomeGuide. “Helical Piers Cost.” https://homeguide.com/costs/helical-piers-cost
23. [39] KC Pier. “How Much Does Foundation Repair Cost? 2025 Update.” https://www.kcpier.com/how-much-does-foundation-repair-cost-2025-update-kansas-city/
24. [10] Orlando Masonry Contractor. “Structural vs Cosmetic Brick Wall Cracks: How to Tell the Difference.” https://orlandomasonrycontractor.com/structural-vs-cosmetic-brick-wall-cracks-how-to-tell-the-difference/
25. [43] Brick Mason Greenville SC. “Do I Need Brick Wall Crack Repair or Full Foundation Repair?” https://brickmasongreenvillesc.com/do-i-need-brick-wall-crack-repair-or-full-foundation-repair/
26. [25] Brick Doctor. “What Causes Bricks & Mortar to Crack?” https://brickdr.com/what-causes-bricks-mortar-to-crack/
27. [2] Dalinghaus Construction. “Understanding Brick Cracks Signs.” https://www.dalinghausconstruction.com/blog/understanding-brick-cracks-signs/
28. [44] Lesiak Masonry. “When To Worry About Cracks In Brick, Mortar & Bricks.” https://lesiakmasonry.ca/when-to-worry-about-cracks-in-brick-mortar-bricks/
29. [38] HomeGuide. “Helical Piers Cost.” https://homeguide.com/costs/helical-piers-cost
30. [36] Dalinghaus Construction. “Cost of Underpinning: Push Piers vs. Helical Piers.” https://www.dalinghausconstruction.com/blog/cost-of-underpinning-push-piers-vs-helical-piers/
31. [37] PierTech. “How Much Do Helical Piers Cost?” https://www.piertech.com/blog/view/how-much-do-helical-piers-cost
32. [35] TorcSill. “Helical Piers Cost.” https://torcsill.com/feeds/blog/helical-piers-cost
33. [40] Today’s Homeowner. “Helical Piers Cost.” https://todayshomeowner.com/foundation/cost/helical-piers-cost/
34. [30] Groundworks. “What Causes Differential Settlement?” https://www.groundworks.com/glossary/differential-settlement/
35. [28] Foundation Pros of Florida. “What is House Shifting?” https://foundationprosfl.com/what-is-house-shifting/
36. [24] Dalinghaus Construction. “How Much Foundation Settlement is Normal?” https://www.dalinghausconstruction.com/blog/how-much-foundation-settlement-is-normal/
37. [29] EPP Concrete. “Signs Your Home Might Need Foundation Stabilization.” https://eppconcrete.com/signs-your-home-might-need-foundation-stabilization/
38. [8] Dalinghaus Construction. “Understanding Foundation Raising and Differential Settlement.” https://www.dalinghausconstruction.com/blog/understanding-foundation-raising-and-differential-settlement/
39. [3] EDT Engineers. “Learn if Your Home’s Foundation is Built on Expansive Clay Soil.” https://www.edtengineers.com/blog-post/learn-if-your-homes-foundation-built-expansive-clay-soil
40. [21] Basement Waterproofing by Al. “Expansive Soils Foundation Damage.” https://basementwaterproofingbyal.com/waterproofing/expansive-soils-foundation-damage/
41. [4] Quality Foundation Repair Austin. “How Expansive Clay Soils Damage Foundations.” https://qualityfoundationrepairaustin.com/how-expansive-clay-soils-damage-foundations/
42. [19] Houston Press. “Expansive Clay Soil Creates Constant Movement.” https://www.houstonpress.com/?p=408655
43. [20] Morgan Inspection Services. “What is Expansive Soil?” https://www.morganinspectionservices.com/what-is-expansive-soil/
44. [17] Wikipedia. “Shrink-Swell Capacity: USDA COLE Index.” https://en.wikipedia.org/wiki/Shrink%E2%80%93swell_capacity
45. [45] ResearchGate. “Relationship Between Swell Index and Estimated Shrink-Swell.” https://www.researchgate.net/figure/Relationship-between-swell-index-and-estimated-shrink-swell_fig4_237598469
46. [46] ResearchGate. “An Expansive Soil Index for Predicting Shrink-Swell Potential.” https://www.researchgate.net/publication/237598469_An_Expansive_Soil_Index_for_Predicting_Shrink-Swell_Potential
47. [47] Minnesota Board of Water and Soil Resources. “Field Book for Describing and Sampling Soils.” https://bwsr.state.mn.us/sites/default/files/2018-12/WETLANDS_delin_Field_Book_Describing_Sampling_Soils_NRCS_2012.pdf
48. [48] USDA NRCS. “Official Soil Series Description.” https://soilseries.sc.egov.usda.gov/OSD_Docs/B/BLUM.html
49. [5] University of Texas at Austin. “Correia Kumar Zornberg 2023.” https://sites.utexas.edu/zornberg/wp-content/uploads/sites/5286/2024/01/Correia_Kumar_Zornberg_2023.pdf
50. [6] HIE Consulting Engineers. “Here’s What Expansive Soil Problems Look Like.” https://www.hie-ce.com/blog/heres-what-expansive-soil-problems-look-like
51. [16] Colorado Geological Survey. “Expansive Soils.” https://coloradogeologicalsurvey.org/wp-content/uploads/woocommerce_uploads/SP-11.pdf
52. [49] Southampton Town NY. “Section 5.4.4 - Expansive Soils.” https://www.southamptontownny.gov/DocumentCenter/View/3284/05-Section-544---Expansive-Soils
53. [50] Mintek Resources. “Expansive Soils.” https://mintekresources.com/expansive-soils/