Examining Sandy Loam for Residential Support

Examining Sandy Loam for Residential Support

Discussion on the common issues caused by expansive clay in residential foundations

Detailed explanation of sandy loam soil characteristics and properties


Sandy loam soil is a type of soil that gardeners and homeowners often seek after due to its balanced composition and numerous benefits for plant growth and residential landscaping. Hiring a certified contractor ensures proper foundation repair methods are used professional slab foundation repair service building insulation. Understanding its characteristics and properties is essential for anyone considering it for their property.

Sandy loam soil is a mixture that typically consists of sand, silt, and clay in relatively even proportion, though with a slight dominance of sand. This combination gives it unique properties that make it favorable for both agricultural and residential uses.

One of the key characteristics of sandy loam soil is its texture. It feels gritty yet slightly smooth when rubbed between your fingers, indicative of the sand and silt components. This texture allows for excellent drainage, which is crucial for preventing waterlogging and root rot in plants. The sand particles are large enough to create spaces between them, facilitating the easy flow of water and air. This makes sandy loam soil ideal for areas prone to heavy rainfall or for plants that do not thrive in soggy conditions.

Another important property of sandy loam soil is its workability. Due to its balanced composition, this soil type is easy to till and cultivate. It warms up quickly in the spring, allowing for earlier planting seasons. However, its loose structure also means it can be prone to erosion, especially on sloped areas. Implementing erosion control measures such as planting ground cover or using mulch can help mitigate this issue.

Sandy loam soil is also known for its low nutrient content. While this might seem like a drawback, it allows gardeners to have better control over the soil's fertility by adding specific amendments tailored to their plants' needs. Organic matter, such as compost or well-rotted manure, can be incorporated to improve nutrient levels and enhance soil structure.

Moreover, sandy loam soil's pH level tends to be slightly acidic to neutral, which is suitable for a wide range of plant species. However, regular soil testing is recommended to monitor pH levels and make necessary adjustments with lime or sulfur if needed.

In residential settings, sandy loam soil supports a variety of landscaping projects. Its excellent drainage makes it perfect for lawns, gardens, and even athletic fields. The soil's ability to warm up quickly in the spring also benefits early-season vegetables and flowers.

In conclusion, sandy loam soil offers a blend of beneficial characteristics and properties that make it an excellent choice for residential support. Its well-draining texture, ease of workability, and controllable fertility provide a solid foundation for successful gardening and landscaping endeavors. With proper management and care, sandy loam soil can enhance the beauty and functionality of any home landscape.

Analysis of how sandy loam soil impacts residential foundation stability


Sandy loam soil is a mixed soil type composed primarily of sand, silt, and clay particles. Due to its composition, it exhibits a unique set of properties that can significantly impact the stability of residential foundations. Understanding these effects is crucial for ensuring long-term structural integrity in residential constructions.

One of the primary characteristics of sandy loam soil is its relatively high permeability. This means that water can easily pass through it, which can lead to issues such as soil erosion over time. When water seeps through the soil and accumulates beneath a foundation, it can cause the soil to expand and become less stable. This phenomenon, known as soil heave, can exert pressure on the foundation, potentially leading to cracks and structural instability.

Additionally, sandy loam soil tends to have lower cohesion compared to other soil types, such as clay. Cohesion refers to the ability of soil particles to stick together. Lower cohesion means that the soil particles are more likely to move independently, especially when subjected to external forces like water flow or vibrations from nearby construction activities. This lack of cohesion can undermine the foundation, making it more susceptible to shifting or settling unevenly.

Another factor to consider is the impact of seasonal changes on sandy loam soil. During wet seasons, the soil may absorb a significant amount of water, causing it to swell. Conversely, during dry seasons, the soil can shrink as it loses moisture. These volume changes can exert varying pressures on the foundation, leading to differential settlement-a situation where different parts of the foundation settle at different rates. This can result in structural stress and, over time, may lead to visible cracks in walls and floors.

To mitigate these risks, engineers and builders often employ specific strategies when constructing on sandy loam soil. One common approach is the use of deeper foundations, such as piles or caissons, which extend below the active zone of soil movement. This helps distribute the weight of the structure more evenly and reduces the impact of soil expansion and contraction.

Additionally, proper drainage systems are essential to manage water flow around the foundation. French drains, for example, can redirect water away from the foundation, minimizing the risk of soil saturation and associated heave.

In conclusion, sandy loam soil presents unique challenges for residential foundation stability due to its high permeability, lower cohesion, and susceptibility to seasonal volume changes. By understanding these properties and implementing appropriate engineering solutions, it is possible to construct stable and durable residential structures even on this type of soil. Careful planning and execution are key to ensuring long-term structural integrity and peace of mind for homeowners.

Common issues faced by homes built on sandy loam soil


When it comes to building homes, the type of soil on which they are constructed plays a crucial role in their stability and longevity. Sandy loam soil, a mixture of sand, silt, and a smaller amount of clay, is often seen as a favorable option due to its balanced composition. However, homes built on sandy loam soil can face a unique set of challenges that homeowners and builders need to be aware of.

One of the most common issues with sandy loam soil is its tendency to erode. Unlike clay soils, which are more cohesive, sandy loam soil can be easily washed away by heavy rains or strong winds. This erosion can undermine the foundation of a home, leading to cracks in walls, uneven floors, and other structural problems. To mitigate this risk, proper drainage systems must be installed around the property to redirect water away from the foundation.

Another challenge is the soil's susceptibility to shifting. Sandy loam soil doesn't hold water as well as clay soils, which means it can dry out and shrink during periods of drought. Conversely, it can become saturated and expand when it rains heavily. This constant expansion and contraction can put stress on a home's foundation, leading to settlement issues. Builders often use specialized foundation techniques, such as pier and beam or slab-on-grade, to accommodate these movements.

Moreover, sandy loam soil can be less supportive than other soil types, making it harder to achieve a stable foundation. This is particularly problematic in areas prone to earthquakes or other seismic activities. To address this, engineers may opt for deeper foundations or use additional reinforcement materials to ensure the home remains secure.

Lastly, sandy loam soil can be more difficult to work with during construction. Its loose nature means it doesn't compact as well as other soils, which can lead to uneven settling over time. This requires careful planning and execution during the building process to ensure the home remains level and stable.

In conclusion, while sandy loam soil offers certain advantages for home construction, it also presents unique challenges that must be carefully managed. From erosion and shifting to foundation stability and construction difficulties, homeowners and builders alike need to be well-informed about these issues to ensure a safe and durable living environment.

Techniques and methods for assessing sandy loam soil in residential areas


Assessing sandy loam soil in residential areas is crucial for ensuring the stability and safety of homes and other structures. Sandy loam soil, a mixture of sand, silt, and a smaller amount of clay, offers unique challenges and benefits for construction and gardening. Here are some techniques and methods used to evaluate this type of soil effectively.

Firstly, soil sampling is a fundamental technique. This involves taking samples from various depths and locations within the property to get a comprehensive understanding of the soil composition. The samples are then analyzed in a laboratory to determine the proportions of sand, silt, and clay, as well as other important factors like pH, organic matter content, and nutrient levels.

Another essential method is the use of a soil penetrometer. This device measures the soil's resistance to penetration, providing insights into its compactness and load-bearing capacity. This information is vital for determining whether the soil can support the weight of a house or other structures without settling or shifting.

Infiltration tests are also commonly used to assess sandy loam soil. These tests measure how quickly water permeates the soil, which is important for understanding drainage capabilities. Poor drainage can lead to waterlogging, which can undermine the stability of foundations and promote the growth of mold and mildew.

Additionally, performing a percolation test can provide valuable data on the soil's ability to absorb and filter water. This test is particularly important in areas where septic systems are used, as it ensures that the soil can handle the effluent without contaminating groundwater.

Lastly, employing geospatial technology, such as drones and Geographic Information Systems (GIS), can offer a broader perspective on the soil conditions across a residential area. These tools can map variations in soil types and properties, helping to identify potential problem areas before construction begins.

In conclusion, assessing sandy loam soil in residential areas requires a multi-faceted approach that combines traditional sampling and testing methods with modern technology. By understanding the unique properties of sandy loam soil, homeowners and builders can make informed decisions that ensure the longevity and safety of residential structures.

Effective strategies for repairing foundations on sandy loam soil


When it comes to building a sturdy residential foundation, the type of soil beneath plays a crucial role. Sandy loam soil, a mixture of sand, silt, and a smaller amount of clay, presents unique challenges and opportunities for foundation repair. Understanding the properties of sandy loam and employing effective strategies can ensure a stable and durable foundation.

Firstly, it's important to recognize that sandy loam soil drains well but may not offer the same level of structural support as clay or loam soils. This characteristic means that foundations built on sandy loam are more susceptible to shifting and settling. To counteract this, one effective strategy is to use a deeper foundation. By extending the depth of the footings, the structure can reach more stable soil layers beneath the sandy loam, reducing the risk of movement.

Another strategy involves the use of piers or piles. These are driven deep into the ground until they reach a stable soil layer or bedrock. Piers can be made from concrete, steel, or wood, and they provide additional support to the foundation, helping to distribute the weight of the structure more evenly. This method is particularly useful in areas where the sandy loam is particularly loose or prone to erosion.

Soil stabilization is another critical technique. This can be achieved through methods like compaction, where the soil is densely packed to increase its load-bearing capacity. Adding materials like lime or cement can also stabilize the soil, improving its strength and reducing its permeability. This is especially beneficial in sandy loam, which can be prone to water infiltration and erosion.

Regular maintenance and monitoring are also vital. Homeowners should keep an eye on any signs of foundation movement, such as cracks in walls or floors, sticking doors, or uneven floors. Early detection of issues can lead to more straightforward and less costly repairs.

In conclusion, repairing foundations on sandy loam soil requires a combination of deep footings, additional support structures like piers, soil stabilization techniques, and vigilant maintenance. By understanding the unique properties of sandy loam and employing these effective strategies, homeowners can ensure their residential foundations remain stable and secure for years to come.

Case studies showcasing successful foundation repairs on sandy loam soil


Certainly! Examining sandy loam for residential support through case studies on successful foundation repairs is a fascinating and practical approach to understanding the complexities of this soil type. Sandy loam, a mixture of sand, silt, and a smaller amount of clay, presents unique challenges and opportunities for foundation construction and repair. Let's delve into a few illustrative case studies that highlight effective strategies for stabilizing foundations on sandy loam soil.

In one notable case, a residential home in a suburban area faced significant foundation issues due to the shifting nature of the sandy loam beneath it. The homeowners noticed cracks in the walls and uneven floors, classic signs of foundation distress. After a thorough soil analysis, engineers determined that the sandy loam's susceptibility to erosion and shifting under water pressure was the primary cause. To address this, they employed a combination of techniques including the installation of helical piers and the implementation of a comprehensive drainage system around the property. The helical piers, which are screw-like supports driven deep into the ground until they reach stable soil, effectively transferred the home's load to more stable layers beneath the sandy loam. Meanwhile, the drainage system was designed to redirect water away from the foundation, reducing the risk of soil erosion and subsequent foundation movement. The result was a stabilized foundation and a relieved homeowner, showcasing the effectiveness of a tailored approach to sandy loam soil challenges.

Another compelling case study involves a multi-story residential building constructed on sandy loam soil. The building experienced differential settlement, where different parts of the structure settled at different rates, leading to structural stress and cosmetic damage. The repair strategy here involved underpinning the foundation with concrete piles. This method involved drilling holes beneath the existing foundation and filling them with concrete, effectively creating a deeper, more stable foundation. The sandy loam's loose structure required careful management to avoid destabilizing the soil further during the drilling process. Through meticulous planning and execution, the building's foundation was successfully underpinned, eliminating the differential settlement and ensuring the structure's long-term stability.

These case studies underscore the importance of understanding the specific characteristics of sandy loam soil when addressing foundation issues. They demonstrate that with the right approach-whether it's through the use of helical piers, comprehensive drainage systems, or concrete underpinning-successful repairs and stabilizations are achievable. These examples not only provide valuable insights for homeowners and engineers facing similar challenges but also highlight the importance of innovative and tailored solutions in the realm of residential foundation repair on sandy loam soil.



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Radon mitigation is any process used to reduce radon gas concentrations in the breathing zones of occupied buildings, or radon from water supplies. Radon is a significant contributor to environmental radioactivity and indoor air pollution. Exposure to radon can cause serious health problems such as lung cancer.[1]

Mitigation of radon in the air by active soil depressurization is most effective. Concrete slabs, sub-floors, and/or crawlspaces are sealed, an air pathway is then created to exhaust radon above the roof-line, and a radon mitigation fan is installed to run permanently. In particularly troublesome dwellings, air exchangers can be used to reduce indoor radon concentrations. Treatment systems using aeration or activated charcoal are available to remove radon from domestic water supplies. There is no proven link between radon in water and gastrointestinal cancers; however, extremely high radon concentrations in water can be aerosolized by faucets and shower heads and contribute to high indoor radon levels in the air.

Testing

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A typical radon test kit
Fluctuation of ambient air radon concentration over one week, measured in a laboratory

The first step in mitigation is testing. No level of radiation is considered completely safe, but as it cannot be eliminated, governments around the world have set various action levels to provide guidance on when radon concentrations should be reduced. The World Health Organization's International Radon Project has recommended an action level of 100 Bq/m3 (2.7 pCi/L) for radon in the air.[2] Radon in the air is considered to be a larger health threat than radon in domestic water. The US Environmental Protection Agency recommendation is to not test for radon in water unless a radon in air test shows concentrations above the action level. However, in some U.S. states such as Maine where radon levels are higher than the national average, it is recommend that all well water should be tested for radon. The U.S. government has not set an action level for radon in water.

Air-radon levels fluctuate naturally on a daily and seasonal basis. A short term test (90 days or less) might not be an accurate assessment of a home's average radon level, but is recommended for initial testing to quickly determine unhealthy conditions. Transient weather such as wind and changes in barometric pressure can affect short-term concentrations as well as ventilation, such as open windows and the operation of exhaust fans.

Testing for radon in the air is accomplished using passive or active devices placed in the building. Some devices are promptly sent to a laboratory for analysis, others calculate the results on-site including digital Radon detectors. Radon-in-water testing requires a water sample being sent to a laboratory.

Retesting is recommended in several situations, for example, before spending money on the installation of a mitigation system. Test results which exceed accuracy tolerances also require re-testing. When a mitigation system installation is warranted, a retest after the system is functional is advised to be sure the system is effectively reducing the radon concentration below the action level, and after any mitigation system repairs such as replacing a fan unit. The US EPA recommends retesting homes with radon problems every two years to ensure proper system function. Due to the vast fluctuation in indoor radon levels, the EPA recommends all homes be tested at least once every five years.[3]

Testing in the United States

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Radon map of the United States

ASTM E-2121 is a US standard for reducing airborne radon in homes as far as practicable below the action level of 4 picocuries per liter (pCi/L) (148 Bq/m3).[4][5] Some states recommend achieving 2.0 pCi/L or less.

Radon test kits are commercially available[6] and can be used by homeowners and tenants and in limited cases by landlords, except when a property is for sale.

Commercially available test kits include a passive collector that the user places in the lowest livable floor of the house for 2 to 7 days. The user then sends the collector to a laboratory for analysis. Long-term kits, taking collections from 91 days to one year, are also available. Open land test kits can test radon emissions from the land before construction begins, but are not recommended by the EPA because they do not accurately predict the final indoor radon level. The EPA and the National Environmental Health Association have identified 15 types of radon test devices.[7] A Lucas cell is one type of device.

Retesting is specifically recommended in several situations. Measurements between 4 and 10 pCi/L (148 and 370 Bq/m3) warrant a follow-up short-term or long-term radon test before mitigation. Measurements over 10 pCi/L (370 Bq/m3) warrant only another short-term test (not a long-term test) so that abatement measures are not unduly delayed.

Progress has been made regarding radon in the home. A total of 37 states have now[when?] passed legislation requiring home-sellers to disclose known radon levels before completing the transaction (although only a handful have introduced criminal penalties for misrepresentation).[8] And over half the legislatures have written radon into their state's building code.[9] Purchasers of real estate may delay or decline a purchase if the seller has not successfully abated radon to less than 4 pCi/L.

The accuracy of the residential radon test depends upon whether closed house conditions are maintained. Thus the occupants will be instructed not to open windows, etc., for ventilation during the pendency of test, usually two days or more. However, the occupants, if the present owners, will be motivated to pass the test and insure the sale, so they might be tempted to open a window to get a lower radon score. Moreover, there may be children or immature teens or young adults in the house who will open a window for ventilation notwithstanding instructions not to do so, particularly in uncomfortably hot weather. Accordingly, whether the potential purchaser should trust the result of such a test is problematic.

Management of radon service provider certification has evolved since being introduced by the EPA in 1986. In the 1990s this service was "privatized" and the National Environmental Health Association (NEHA) helped transition the voluntary National Radon Proficiency Program (NRPP) to be administered by private firms. As of 2012, the NRPP is administered by the American Association of Radon Scientists and Technologists (AARST).[10]

Some states, such as Maine, require landlords to test their rental properties and turn the results in to the state. In limited cases the landlord or tenants may do the testing themselves. The rules in each state vary. In many cases there are private contractors that will inspect hired by the city.

Testing in Canada

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Health Canada recommends regular annual testing, either by hiring a qualified tester or by using a home-testing kit that should be checked quarterly.[11]

Canadian Government, in conjunction with the territories and provinces, developed the guideline[12] to indicate when remedial action should be taken was originally set at 800 Bq/m3 (becquerels per cubic meter) and since reduced to 200 Bq/m3. This new guideline was approved by the Federal Provincial Territorial Radiation Protection Committee in October 2006.[13]

Testing in the UK

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Radon testing in the UK is managed by UKradon and the UKHSA.[14]

Testing in Norway

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The Norwegian Radiation and Nuclear Safety Authority (DSA) developed the protocol[15] for radon measurements in residential dwellings[16] with respect to rental accommodation, which is governed by The Radiation Protection Regulations.[17]

Methods of radon gas mitigation

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Part of a radon mitigation system including the fan and vent pipe is visible near the gutter downspout.

Because high levels of radon have been found in every state of the United States,[18] testing for radon and installing radon mitigation systems has become a specialized industry since the 1980s. Many states have implemented programs that affect home buying and awareness in the real estate community; however, radon testing and mitigation systems are not generally mandatory unless specified by the local jurisdiction.[19]

Anticipated high radon levels can be mitigated during building design and construction by a combination of ensuring a perfectly sealed foundation, allowing sufficient passive dispersal of under-slab gas around rather than through the building, and proper building ventilation. In many instances, such approaches may achieve a sufficient reduction of radon levels compared to other buildings where such approaches were not taken. However, quality of implementation is crucial and testing after construction is necessary. For instance, even a small gap in the sealing of the slab may be sufficient for excessive quantities of radon to enter, given pressure differentials.

Where such approaches were not taken during construction or have proven insufficiently effective, remediation is needed. According to the EPA's "A Citizen's Guide to Radon",[20] the method to reduce radon "primarily used is a vent pipe system and fan, which pulls radon from beneath the house and vents it to the outside", which is also called sub-slab depressurization, soil suction, or active soil depressurization (ASD). Generally indoor radon can be mitigated by sub-slab depressurization and exhausting such radon-laden air to the outdoors, away from windows and other building openings.[21] "EPA generally recommends methods which prevent the entry of radon. Soil suction, for example, prevents radon from entering your home by drawing the radon from below the home and venting it through a pipe, or pipes, to the air above the home where it is quickly diluted" and "EPA does not recommend the use of sealing alone to reduce radon because, by itself, sealing has not been shown to lower radon levels significantly or consistently" according to the EPA's "Consumer's Guide to Radon Reduction: How to Fix Your Home".[22] Ventilation systems can utilize a heat exchanger or energy recovery ventilator to recover part of the energy otherwise lost in the process of exchanging air with the outside. For crawlspaces, the EPA states,[22] "An effective method to reduce radon levels in crawlspace homes involves covering the earth floor with a high-density plastic sheet. A vent pipe and fan are used to draw the radon from under the sheet and vent it to the outdoors. This form of soil suction is called submembrane suction, and when properly applied is the most effective way to reduce radon levels in crawlspace homes."

High radon levels in a Minnesota (USA) basement with a passive under slab vent pipe system can be seen in the left half of the graph. After installation of a radon fan (ASD), a permanent reduction in radon levels to approximately 0.6 pCi/L can be seen in the right half of the graph.
  • The most common approach is active soil depressurization (ASD). Experience has shown that ASD is applicable to most buildings since radon usually enters from the soil and rock underneath and mechanical ventilation is used when the indoor radon is emitted from the building materials. A less common approach works efficiently by reducing air pressures within cavities of exterior and demising walls where radon emitting from building materials, most often concrete blocks, collects.
  • Above slab air pressure differential barrier technology (ASAPDB) requires that the interior pressure envelope, most often drywall, as well as all ductwork for air conditioning systems, be made as airtight as possible. A small blower, often no more than 15 cubic feet per minute (0.7 L/s) may then extract the radon-laden air from these cavities and exhaust it to the out of doors. With well-sealed HVAC ducts, very small negative pressures, perhaps as little as 0.5 pascal (0.00007 psi), will prevent the entry of highly radon-laden wall cavity air from entering into the breathing zone. Such ASAPDB technology is often the best radon mitigation choice for high-rise condominiums as it does not increase indoor humidity loads in hot humid climates, and it can also work well to prevent mold growth in exterior walls in heating climates.
  • In hot, humid climates, heat recovery ventilators (HRV) as well as energy recovery ventilators (ERV) have a record of increasing indoor relative humidity and dehumidification demands on air conditioning systems. Mold problems can occur in homes that have been radon mitigated with HRV and ERV installations in hot, humid climates.[citation needed] HRVs and ERVs have an excellent record in cold dry climates.
  • A recent technology is based on building science. It includes a variable rate mechanical ventilation system that prevents indoor relative humidity from rising above a preset level such as 50% which is currently suggested by the US Environmental Protection Agency and others as an upper limit for the prevention of mold. It has proven to be especially effective in hot, humid climates. It controls the air delivery rate so that the air conditioner is never overloaded with more moisture than it can effectively remove from the indoor air.
    • It is generally assumed that air conditioner operation will remove excess moisture from the air in the breathing zone, but it is important to note that just because the air conditioner cools does not mean that it is also dehumidfying. If Δt is 14 degrees or less, it may not dehumidify at all even though it is cooling.
    • Factors that are likely to aggravate indoor humidity problems from mechanical ventilation–based radon installations are as follows and an expert radon mitigator/building scientist will check for and correct any and all of the following when he or she performs radon mitigation procedures:
      • Air conditioner duct leaks located outside the breathing zone, such as in the attic.
      • Excessive exhaust fan operation
      • Oversize or over-capacity air conditioners
      • AC air handler fans that do not stop running when the air conditioner compressor stops running.
      • Delta tt), which is the amount that the air is cooled as it is passed through the air conditioner's cooling coils. A good Δt performance figure for home air conditioners is about 20 °F (11 °C). In comparison, automobile air conditioners deliver Δt performance of 32 to 38 °F (18 to 21 °C). A Δt of 14 °F (8 °C) will dehumidify poorly if at all.

In South Florida, most radon mitigation is performed by use of fixed rate mechanical ventilation. Radon mitigation training in Florida does not include problems associated with mechanical ventilation systems, such as high indoor humidity, mold, moldy odors, property damage or health consequences of human occupation in high humidity of moldy environments[citation needed]. As a result, most Florida radon mitigators are unaware of and do not incorporate existing building science moisture management technology into mechanical ventilation radon installations. Home inspectors may not necessarily be aware of the mold risks associated with radon mitigation by mechanical ventilation.

The average cost for an ASD radon mitigation system in Minnesota is $1500.[23] These costs are very dependent on the type of home and age of construction.[24]

Methods of radon-in-water mitigation

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Radon removal from water supplies may be at a treatment plant, point of entry, or point of use. Public water supplies in the United States were required to treat for radionuclides beginning in 2003 but private wells are not regulated by the federal government as of 2014. The radon can be captured by granular activated charcoal (GAR) or released into the air through aeration of the water. Radon will naturally dissipate from water over a period of days, but the quantity of storage needed to treat the water in this manner makes home systems of this type impracticably large.[25]

Activated carbon systems capture radon from the water. The amount of radiation accumulates over time and the filter material may reach the level of requiring disposal as a radioactive waste. However, in the United States there are no regulations concerning radiation levels and disposal of radon treatment waste as of 2014.

Aeration systems move the radon from the water to the air. Radon gas discharged into the air is the release of a pollutant, and may become regulated in the United States.

References

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  1. ^ Nunnally, Diamond (2022-03-30). "Dangerous radon gas dangers and detection tips". WBMA. Retrieved 2022-04-10.
  2. ^ WHO Handbook on Indoor Radon: A Public Health Perspective. World Health Organization. 2009.
  3. ^ US EPA, OAR (2013-08-27). "Radon". www.epa.gov. Retrieved 2023-02-04.
  4. ^ "Recommended Residential Radon Mitigation Standard of Practice". United States Environmental Protection Agency. Archived from the original on 2008-01-16. Retrieved 2008-02-02.
  5. ^ "ASTM E2121-03 Standard Practice for Installing Radon Mitigation Systems in Existing Low-Rise Residential Buildings". ASTM International. Retrieved 2008-02-02.
  6. ^ "Commercially Available Radon Kits". Alpha Energy Labs. Archived from the original on 2012-07-12. Retrieved 2012-04-19.
  7. ^ "Radon Measurement Method Definitions". The National Environmental Health Association—National Radon Proficiency Program. Archived from the original on 2007-12-24. Retrieved 2008-02-02.
  8. ^ "State Radon Laws". lawatlas.org. Retrieved 2021-07-12.
  9. ^ "National Conference of State Legislatures (NCSL) - Radon".
  10. ^ "National Radon Proficiency Program - NEHA and NEHA-NRPP History". Nrpp.info. Retrieved 2015-03-30.
  11. ^ "Home radon testing important for health". lethbridgeherald.com. 18 March 2022. Retrieved 2022-04-10.
  12. ^ "Radon Gas | Vancouver, BC, Canada". Radoncontrol.ca. Retrieved 2015-03-30.
  13. ^ "Radon Frequently Asked Questions - Health Canada". Hc-sc.gc.ca. 2014-07-30. Retrieved 2015-03-30.
  14. ^ "UKradon - Home". www.ukradon.org.
  15. ^ "Radon measurements in residential dwellings".
  16. ^ "Radon boliger 2013" (PDF).
  17. ^ "Legislation".
  18. ^ "Radon: Myth vs Fact". Radon-Rid/EPA. Retrieved 2009-11-13.
  19. ^ "Listing of States and Jurisdictions with RRNC Codes". EPA. Retrieved 2009-11-13.
  20. ^ "A Citizen's Guide to Radon" (PDF). EPA. Retrieved 2024-12-27.
  21. ^ "Radon Mitigation Methods". Radon Solution. Archived from the original on 2008-12-15. Retrieved 2008-12-02.
  22. ^ a b "Consumer's Guide to Radon Reduction: How to Fix Your Home" (PDF). EPA.
  23. ^ "Radon Mitigation System - EH: Minnesota Department of Health". Health.state.mn.us. 2014-12-10. Retrieved 2019-03-26.
  24. ^ "Featured Radon Mitigation System Archives". Radonreductioninc.com. Retrieved 2015-03-30.
  25. ^ ""Radon in Drinking Water Health Risk Reduction and Cost Analysis: Notice"" (PDF). Federal Register. 64. February 26, 1999. Retrieved 2015-03-30.
[edit]
  • Radon at the United States Environmental Protection Agency
  • National Radon Program Services hosted by Kansas State University
  • Radon and Lung Health from the American Lung Association
  • It's Your Health - Health Canada
  • Radon's impact on your health – Quebec Lung Association

 

In geotechnical engineering, soil compaction is the process in which stress applied to a soil causes densification as air is displaced from the pores between the soil grains. When stress is applied that causes densification due to water (or other liquid) being displaced from between the soil grains, then consolidation, not compaction, has occurred. Normally, compaction is the result of heavy machinery compressing the soil, but it can also occur due to the passage of, for example, animal feet.

In soil science and agronomy, soil compaction is usually a combination of both engineering compaction and consolidation, so may occur due to a lack of water in the soil, the applied stress being internal suction due to water evaporation[1] as well as due to passage of animal feet. Affected soils become less able to absorb rainfall, thus increasing runoff and erosion. Plants have difficulty in compacted soil because the mineral grains are pressed together, leaving little space for air and water, which are essential for root growth. Burrowing animals also find it a hostile environment, because the denser soil is more difficult to penetrate. The ability of a soil to recover from this type of compaction depends on climate, mineralogy and fauna. Soils with high shrink–swell capacity, such as vertisols, recover quickly from compaction where moisture conditions are variable (dry spells shrink the soil, causing it to crack). But clays such as kaolinite, which do not crack as they dry, cannot recover from compaction on their own unless they host ground-dwelling animals such as earthworms—the Cecil soil series is an example.

Before soils can be compacted in the field, some laboratory tests are required to determine their engineering properties. Among various properties, the maximum dry density and the optimum moisture content are vital and specify the required density to be compacted in the field.[2]

A 10 tonne excavator is here equipped with a narrow sheepsfoot roller to compact the fill over newly placed sewer pipe, forming a stable support for a new road surface.
A compactor/roller fitted with a sheepsfoot drum, operated by U.S. Navy Seabees
Vibrating roller with plain drum as used for compacting asphalt and granular soils
Vibratory rammer in action

In construction

[edit]

Soil compaction is a vital part of the construction process. It is used for support of structural entities such as building foundations, roadways, walkways, and earth retaining structures to name a few. For a given soil type certain properties may deem it more or less desirable to perform adequately for a particular circumstance. In general, the preselected soil should have adequate strength, be relatively incompressible so that future settlement is not significant, be stable against volume change as water content or other factors vary, be durable and safe against deterioration, and possess proper permeability.[3]

When an area is to be filled or backfilled the soil is placed in layers called lifts. The ability of the first fill layers to be properly compacted will depend on the condition of the natural material being covered. If unsuitable material is left in place and backfilled, it may compress over a long period under the weight of the earth fill, causing settlement cracks in the fill or in any structure supported by the fill.[4] In order to determine if the natural soil will support the first fill layers, an area can be proofrolled. Proofrolling consists of utilizing a piece of heavy construction equipment to roll across the fill site and watching for deflections to be revealed. These areas will be indicated by the development of rutting, pumping, or ground weaving.[5]

To ensure adequate soil compaction is achieved, project specifications will indicate the required soil density or degree of compaction that must be achieved. These specifications are generally recommended by a geotechnical engineer in a geotechnical engineering report.

The soil type—that is, grain-size distributions, shape of the soil grains, specific gravity of soil solids, and amount and type of clay minerals, present—has a great influence on the maximum dry unit weight and optimum moisture content.[6] It also has a great influence on how the materials should be compacted in given situations. Compaction is accomplished by use of heavy equipment. In sands and gravels, the equipment usually vibrates, to cause re-orientation of the soil particles into a denser configuration. In silts and clays, a sheepsfoot roller is frequently used, to create small zones of intense shearing, which drives air out of the soil.

Determination of adequate compaction is done by determining the in-situ density of the soil and comparing it to the maximum density determined by a laboratory test. The most commonly used laboratory test is called the Proctor compaction test and there are two different methods in obtaining the maximum density. They are the standard Proctor and modified Proctor tests; the modified Proctor is more commonly used. For small dams, the standard Proctor may still be the reference.[5]

While soil under structures and pavements needs to be compacted, it is important after construction to decompact areas to be landscaped so that vegetation can grow.

Compaction methods

[edit]

There are several means of achieving compaction of a material. Some are more appropriate for soil compaction than others, while some techniques are only suitable for particular soils or soils in particular conditions. Some are more suited to compaction of non-soil materials such as asphalt. Generally, those that can apply significant amounts of shear as well as compressive stress, are most effective.

The available techniques can be classified as:

  1. Static – a large stress is slowly applied to the soil and then released.
  2. Impact – the stress is applied by dropping a large mass onto the surface of the soil.
  3. Vibrating – a stress is applied repeatedly and rapidly via a mechanically driven plate or hammer. Often combined with rolling compaction (see below).
  4. Gyrating – a static stress is applied and maintained in one direction while the soil is a subjected to a gyratory motion about the axis of static loading. Limited to laboratory applications.
  5. Rolling – a heavy cylinder is rolled over the surface of the soil. Commonly used on sports pitches. Roller-compactors are often fitted with vibratory devices to enhance their effectiveness.
  6. Kneading – shear is applied by alternating movement in adjacent positions. An example, combined with rolling compaction, is the 'sheepsfoot' roller used in waste compaction at landfills.

The construction plant available to achieve compaction is extremely varied and is described elsewhere.

Test methods in laboratory

[edit]

Soil compactors are used to perform test methods which cover laboratory compaction methods used to determine the relationship between molding water content and dry unit weight of soils. Soil placed as engineering fill is compacted to a dense state to obtain satisfactory engineering properties such as, shear strength, compressibility, or permeability. In addition, foundation soils are often compacted to improve their engineering properties. Laboratory compaction tests provide the basis for determining the percent compaction and molding water content needed to achieve the required engineering properties, and for controlling construction to assure that the required compaction and water contents are achieved. Test methods such as EN 13286-2, EN 13286-47, ASTM D698, ASTM D1557, AASHTO T99, AASHTO T180, AASHTO T193, BS 1377:4 provide soil compaction testing procedures.[7]

See also

[edit]
  • Soil compaction (agriculture)
  • Soil degradation
  • Compactor
  • Earthwork
  • Soil structure
  • Aeration
  • Shear strength (soil)
Multiquip RX1575 Rammax Sheepsfoot Trench Compaction Roller on the jobsite in San Diego, California

References

[edit]
  1. ^ Soil compaction due to lack of water in soil
  2. ^ Jia, Xiaoyang; Hu, Wei; Polaczyk, Pawel; Gong, Hongren; Huang, Baoshan (2019). "Comparative Evaluation of Compacting Process for Base Materials using Lab Compaction Methods". Transportation Research Record: Journal of the Transportation Research Board. 2673 (4): 558–567. doi:10.1177/0361198119837953. ISSN 0361-1981.
  3. ^ McCarthy, David F. (2007). Essentials of Soil Mechanics and Foundations. Upper Saddle River, NJ: Pearson Prentice Hall. p. 595. ISBN 978-0-13-114560-3.
  4. ^ McCarthy, David F. (2007). Essentials of Soil Mechanics and Foundations. Upper Saddle River, NJ: Pearson Prentice Hall. pp. 601–602. ISBN 978-0-13-114560-3.
  5. ^ a b McCarthy, David F. (2007). Essentials of Soil Mechanics and Foundations. Upper Saddle River, NJ: Pearson Prentice Hall. p. 602. ISBN 978-0-13-114560-3.
  6. ^ Das, Braja M. (2002). Principles of Geotechnical Engineering. Pacific Grove, CA: Brooks/Cole. p. 105. ISBN 0-534-38742-X.
  7. ^ "Automatic Soil Compactor". cooper.co.uk. Cooper Research Technology. Archived from the original on 27 August 2014. Retrieved 8 September 2014.

 

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Reviews for


Jeffery James

(5)

Very happy with my experience. They were prompt and followed through, and very helpful in fixing the crack in my foundation.

Sarah McNeily

(5)

USS was excellent. They are honest, straightforward, trustworthy, and conscientious. They thoughtfully removed the flowers and flower bulbs to dig where they needed in the yard, replanted said flowers and spread the extra dirt to fill in an area of the yard. We've had other services from different companies and our yard was really a mess after. They kept the job site meticulously clean. The crew was on time and friendly. I'd recommend them any day! Thanks to Jessie and crew.

Jim de Leon

(5)

It was a pleasure to work with Rick and his crew. From the beginning, Rick listened to my concerns and what I wished to accomplish. Out of the 6 contractors that quoted the project, Rick seemed the MOST willing to accommodate my wishes. His pricing was definitely more than fair as well. I had 10 push piers installed to stabilize and lift an addition of my house. The project commenced at the date that Rick had disclosed initially and it was completed within the same time period expected (based on Rick's original assessment). The crew was well informed, courteous, and hard working. They were not loud (even while equipment was being utilized) and were well spoken. My neighbors were very impressed on how polite they were when they entered / exited my property (saying hello or good morning each day when they crossed paths). You can tell they care about the customer concerns. They ensured that the property would be put back as clean as possible by placing MANY sheets of plywood down prior to excavating. They compacted the dirt back in the holes extremely well to avoid large stock piles of soils. All the while, the main office was calling me to discuss updates and expectations of completion. They provided waivers of lien, certificates of insurance, properly acquired permits, and JULIE locates. From a construction background, I can tell you that I did not see any flaws in the way they operated and this an extremely professional company. The pictures attached show the push piers added to the foundation (pictures 1, 2 & 3), the amount of excavation (picture 4), and the restoration after dirt was placed back in the pits and compacted (pictures 5, 6 & 7). Please notice that they also sealed two large cracks and steel plated these cracks from expanding further (which you can see under my sliding glass door). I, as well as my wife, are extremely happy that we chose United Structural Systems for our contractor. I would happily tell any of my friends and family to use this contractor should the opportunity arise!

Chris Abplanalp

(5)

USS did an amazing job on my underpinning on my house, they were also very courteous to the proximity of my property line next to my neighbor. They kept things in order with all the dirt/mud they had to excavate. They were done exactly in the timeframe they indicated, and the contract was very details oriented with drawings of what would be done. Only thing that would have been nice, is they left my concrete a little muddy with boot prints but again, all-in-all a great job

Dave Kari

(5)

What a fantastic experience! Owner Rick Thomas is a trustworthy professional. Nick and the crew are hard working, knowledgeable and experienced. I interviewed every company in the area, big and small. A homeowner never wants to hear that they have foundation issues. Out of every company, I trusted USS the most, and it paid off in the end. Highly recommend.

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