Approaches for Chemical Soil Stabilization

Approaches for Chemical Soil Stabilization

Description of the techniques and materials used in repairing foundations affected by expansive clay

Overview of common soil types and their challenges in residential construction.


In residential construction, understanding the soil types one is working with is crucial. Helical piers provide strong support for homes needing foundation repair expert service residential foundation repair service integrity. Different soils present unique challenges that can affect the stability and longevity of structures. Let's delve into some common soil types and the hurdles they pose, followed by an introduction to chemical soil stabilization as a potential solution.

Clay soils are notorious for their high plasticity and cohesion. While they can provide good support when dry, they tend to expand when wet, leading to foundation issues. This expansion can cause cracks in walls and uneven settling, compromising the structural integrity of a home.

Sandy soils, on the other hand, are loose and granular. They offer poor support for foundations due to their low cohesion and high permeability. Structures built on sandy soils are susceptible to sinking or shifting, especially during heavy rains or earthquakes.

Silt soils fall between clay and sand in terms of particle size. They are more stable than sandy soils but can still pose challenges. Silt soils have a tendency to compact under load, which can lead to settling issues over time. Additionally, they can become slippery when wet, making them difficult to work with during construction.

Peat soils are organic and highly compressible. They are often found in wetland areas and can pose significant challenges for construction. Peat soils have a high water content and low bearing capacity, making them unsuitable for supporting heavy structures without proper stabilization.

Chemical soil stabilization offers a promising approach to addressing these challenges. By introducing chemical agents into the soil, engineers can alter its properties to improve stability and load-bearing capacity. Common chemicals used in soil stabilization include lime, cement, and fly ash.

Lime stabilization involves mixing lime with the soil to induce chemical reactions that bind soil particles together. This process increases the soil's cohesion and reduces its plasticity, making it more suitable for construction.

Cement stabilization works similarly by forming a cementitious matrix within the soil. This matrix binds soil particles together, enhancing the soil's strength and durability.

Fly ash, a byproduct of coal combustion, can also be used for soil stabilization. When mixed with lime or cement, fly ash can improve the soil's compaction characteristics and reduce its susceptibility to swelling and shrinkage.

In conclusion, understanding the challenges posed by different soil types is essential in residential construction. Chemical soil stabilization offers a viable solution to overcome these challenges, ensuring the stability and longevity of structures built on problematic soils. By employing the right chemical agents and techniques, engineers can transform unsuitable soils into stable foundations for residential developments.

Detailed explanation of various chemical agents used for soil stabilization, including lime, cement, and polymers.


Certainly! When it comes to enhancing the properties of soil for construction and other purposes, chemical soil stabilization is a widely adopted method. This approach involves the addition of chemical agents to alter the soil's physical and chemical characteristics, improving its strength, durability, and resistance to environmental factors. Among the various chemical agents used for this purpose, lime, cement, and polymers stand out for their effectiveness and versatility.

Lime stabilization is one of the oldest and most commonly used methods. Lime, primarily calcium oxide (CaO) or calcium hydroxide (Ca(OH)2), reacts with the clay minerals in the soil to form cementitious compounds. This reaction, known as pozzolanic reaction, significantly improves the soil's load-bearing capacity and reduces its plasticity. Lime stabilization is particularly effective in treating clayey soils, making them more stable and less susceptible to volume changes due to moisture variations.

Cement stabilization, on the other hand, involves mixing Portland cement with the soil. The cement reacts with the soil particles to form a solid mass, much like concrete. This method is highly effective in increasing the soil's compressive strength and durability. Cement stabilization is versatile and can be used in a variety of soil types, though it is particularly beneficial for sandy and gravelly soils where lime might not be as effective.

Polymers represent a more modern approach to chemical soil stabilization. These synthetic materials, including latex, acrylics, and lignin-based compounds, are added to the soil to bind the particles together. Polymers can significantly enhance the soil's strength, impermeability, and resistance to erosion. They are particularly useful in applications where flexibility and resistance to chemical attack are required. Polymers are also valued for their ability to improve the soil's workability and reduce dust, making them a preferred choice in urban and sensitive environmental settings.

Each of these chemical agents - lime, cement, and polymers - offers unique benefits and is chosen based on the specific requirements of the project, the type of soil being treated, and the environmental conditions. The selection of the appropriate chemical agent is crucial for achieving the desired stabilization effects and ensuring the longevity and performance of the stabilized soil in its intended application.

Step-by-step process of applying chemical soil stabilization techniques in residential foundation repair.


Certainly! Here's a short essay on the step-by-step process of applying chemical soil stabilization techniques in residential foundation repair:

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Chemical soil stabilization is a sophisticated method used in residential foundation repair to enhance the load-bearing capacity and durability of the soil. This technique involves the addition of chemical agents to the soil, which react with the soil particles to form a stronger and more stable structure. Here's a step-by-step guide to applying chemical soil stabilization in residential foundation repair:

1. **Site Assessment**: The first step is a thorough site assessment. This involves evaluating the soil type, moisture content, and the extent of foundation damage. Professionals use various tools and tests to determine the specific characteristics of the soil and the appropriate chemical agents to use.

2. **Selection of Chemical Agents**: Based on the site assessment, suitable chemical agents are selected. Common chemicals used include lime, cement, and various polymers. Each chemical has unique properties that make it effective for different soil types and conditions.

3. **Preparation of the Area**: The area around the foundation is prepared by removing any debris, vegetation, and existing soil to a certain depth. This ensures that the chemical agents can be evenly distributed and effectively penetrate the soil.

4. **Application of Chemical Agents**: The chosen chemical agents are mixed with water to create a slurry. This slurry is then injected into the soil using specialized equipment. The injection process ensures that the chemicals reach the desired depth and are uniformly distributed throughout the soil mass.

5. **Mixing and Curing**: After the chemicals are injected, the soil is mechanically mixed to ensure thorough integration of the chemical agents with the soil particles. This mixing process is crucial for the chemical reactions to occur effectively. Following mixing, the soil is left to cure. During this period, the chemical reactions strengthen the soil structure.

6. **Monitoring and Testing**: Throughout the process, regular monitoring and testing are conducted to ensure that the chemical stabilization is proceeding as planned. Soil samples are taken and tested for strength and stability to confirm that the desired results are being achieved.

7. **Final Inspection**: Once the curing period is complete, a final inspection is performed. This includes checking the stability of the foundation and ensuring that the chemical stabilization has effectively addressed the issues. Any necessary adjustments or additional treatments are made at this stage.

8. **Restoration**: Finally, the area is restored to its original state. This may involve backfilling with treated soil, reinstalling any removed structures, and landscaping to match the surrounding area.

In conclusion, the step-by-step process of applying chemical soil stabilization techniques in residential foundation repair is a meticulous and scientific approach. It requires careful assessment, precise application of chemical agents, and thorough monitoring to ensure long-lasting results and a stable foundation.

Case studies showcasing successful applications of chemical soil stabilization in residential projects.


Chemical soil stabilization has emerged as a vital technique in the realm of civil engineering, particularly for residential projects where soil conditions may pose challenges to construction. This method involves the addition of chemical agents to soils to enhance their engineering properties, such as strength, durability, and resistance to erosion. Several case studies have demonstrated the successful application of chemical soil stabilization in residential settings, highlighting its effectiveness and versatility.

One notable case study involves a residential development project in a region with expansive clay soils. These soils are notorious for their tendency to swell and shrink with changes in moisture content, leading to foundation problems and structural damage. To mitigate these risks, the project employed a chemical stabilization approach using lime and cement. The treatment significantly reduced the soil's expansiveness, providing a stable foundation for the homes. Post-construction monitoring showed minimal movement in the soil, ensuring the longevity and safety of the structures.

Another compelling example is the rehabilitation of a historic neighborhood where the soil had been contaminated with heavy metals from past industrial activities. Traditional excavation and disposal methods were deemed too costly and disruptive. Instead, the project team opted for in-situ chemical stabilization using a combination of phosphate-based compounds and organic amendments. This approach not only immobilized the contaminants but also improved the soil's load-bearing capacity. The revitalized soil supported new residential constructions while safeguarding the environment and preserving the neighborhood's historical integrity.

In a coastal area prone to erosion, a residential community faced the dual challenges of weak, sandy soils and the threat of sea-level rise. Chemical stabilization using a polymer-based solution was implemented to enhance the soil's cohesion and resistance to water. The treated soil provided a robust foundation for the homes, while also acting as a barrier against erosion. This innovative approach not only addressed the immediate construction needs but also contributed to the community's long-term resilience against climate change impacts.

These case studies underscore the adaptability and effectiveness of chemical soil stabilization in residential projects. By tailoring the chemical agents to the specific soil conditions and project requirements, engineers can achieve significant improvements in soil performance. As urban development continues to expand into areas with challenging soil conditions, chemical stabilization offers a promising solution for ensuring the stability and durability of residential structures.

Benefits of using chemical soil stabilization over traditional methods, such as improved load-bearing capacity and durability.


Chemical soil stabilization offers numerous advantages over traditional soil treatment methods, making it an increasingly popular choice for civil engineering projects. One of the primary benefits is the significant improvement in load-bearing capacity. When chemicals like lime, cement, or fly ash are introduced into the soil, they react with the soil particles to form stronger bonds. This results in a more robust and stable foundation that can support heavier loads without compromising integrity. This is particularly crucial in construction projects where the soil's natural bearing capacity is insufficient to support the intended structures.

Another notable benefit is the enhanced durability of the stabilized soil. Traditional methods, such as mechanical compaction or the addition of gravel, often provide only temporary solutions. In contrast, chemical stabilization creates a lasting change in the soil's properties. The chemical reactions that occur during stabilization produce a more cohesive and resilient soil matrix. This means that the stabilized soil is better equipped to withstand environmental stresses such as freeze-thaw cycles, moisture variations, and erosion. As a result, the longevity of the soil improvement is extended, reducing the need for frequent maintenance or repairs.

Moreover, chemical soil stabilization can lead to cost savings in the long run. Although the initial investment may be higher compared to traditional methods, the durability and performance of the stabilized soil often result in lower overall costs. Projects that utilize chemical stabilization may experience fewer disruptions and delays due to soil-related issues, leading to more efficient project timelines and reduced labor costs. Additionally, the improved load-bearing capacity allows for the use of thinner pavement layers or lighter structural elements, further cutting down on material expenses.

In summary, the benefits of using chemical soil stabilization over traditional methods are clear. The improved load-bearing capacity and durability it offers not only enhance the performance and longevity of construction projects but also contribute to cost efficiency and sustainability. As technology and methodologies continue to advance, chemical soil stabilization is likely to become an even more integral part of modern civil engineering practices.

Potential drawbacks and limitations of chemical soil stabilization, including cost and environmental impact.


Chemical soil stabilization is a method used to improve the properties of soil, making it more suitable for construction and other purposes. While this approach offers numerous benefits, such as increased soil strength, reduced permeability, and enhanced durability, it is not without its potential drawbacks and limitations. These include cost considerations and environmental impacts, which are crucial factors to evaluate when deciding on the suitability of chemical stabilization for a specific project.

One of the primary concerns with chemical soil stabilization is the cost. The process can be expensive, particularly when large volumes of soil need treatment. The cost is influenced by several factors, including the type and amount of chemical additives required, the scale of the project, and the labor involved in the application process. In some cases, the initial investment might be justifiable considering the long-term benefits, but for smaller projects or those with limited budgets, the expense can be prohibitive.

Environmental impact is another significant consideration. The chemicals used in soil stabilization, such as lime, cement, or more specialized agents like polymers and resins, can have varying effects on the environment. Some chemicals may leach into groundwater, potentially contaminating water sources and affecting local ecosystems. Moreover, the production and transportation of these chemicals contribute to carbon emissions and other environmental footprints. Therefore, it is essential to assess the ecological consequences and strive for more sustainable practices, such as using eco-friendly additives or implementing measures to mitigate adverse effects.

Additionally, the effectiveness of chemical stabilization can be limited by site-specific conditions. The success of the treatment depends on factors like soil type, moisture content, and existing contaminants. In some cases, the soil may not respond as expected to the chemicals, leading to suboptimal results. This unpredictability requires thorough site investigations and testing to ensure the chosen method will be effective.

In conclusion, while chemical soil stabilization offers valuable solutions for improving soil properties, it is imperative to consider the potential drawbacks and limitations. Costs and environmental impacts are significant factors that must be weighed against the benefits. By carefully evaluating these aspects and adopting sustainable practices, it is possible to mitigate some of the negative effects and make informed decisions for successful project outcomes.

Future trends and innovations in chemical soil stabilization for residential foundation repair services.


In recent years, the field of residential foundation repair has seen significant advancements, particularly in the realm of chemical soil stabilization. This approach involves the use of various chemicals to improve the structural integrity of soil, thereby enhancing the stability of foundations. As we look towards the future, several trends and innovations are poised to revolutionize this sector.

One of the most promising trends is the development of eco-friendly chemicals for soil stabilization. Traditional methods often relied on harsh chemicals that could have detrimental effects on the environment. However, new formulations are being developed that are not only effective but also environmentally sustainable. These chemicals are designed to minimize ecological impact while still providing robust soil stabilization.

Another innovation on the horizon is the use of nanotechnology in chemical soil stabilization. By employing nanoparticles, it's possible to achieve a more uniform distribution of stabilizing agents within the soil. This results in enhanced performance and durability of the foundation. Nanotechnology also allows for targeted treatment, meaning that only the areas in need of stabilization are treated, thereby reducing waste and cost.

Additionally, there is a growing interest in smart materials for soil stabilization. These materials can respond to environmental changes, such as shifts in moisture or temperature, by adjusting their properties to maintain stability. This adaptive capability ensures that the foundation remains robust under varying conditions, offering long-term benefits for homeowners.

Furthermore, the integration of digital technologies is set to transform the way chemical soil stabilization is implemented. Advanced software and machine learning algorithms can analyze soil conditions more accurately, allowing for precise application of stabilizing chemicals. This not only improves the effectiveness of the treatment but also reduces the time and labor required for foundation repair.

In conclusion, the future of chemical soil stabilization in residential foundation repair is bright, with a strong emphasis on sustainability, precision, and innovation. As these trends and technologies continue to evolve, they promise to deliver more efficient, effective, and environmentally friendly solutions for homeowners facing foundation issues.



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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

 

A load-bearing wall or bearing wall is a wall that is an active structural element of a building, which holds the weight of the elements above it, by conducting its weight to a foundation structure below it.

Load-bearing walls are one of the earliest forms of construction. The development of the flying buttress in Gothic architecture allowed structures to maintain an open interior space, transferring more weight to the buttresses instead of to central bearing walls. In housing, load-bearing walls are most common in the light construction method known as "platform framing". In the birth of the skyscraper era, the concurrent rise of steel as a more suitable framing system first designed by William Le Baron Jenney, and the limitations of load-bearing construction in large buildings, led to a decline in the use of load-bearing walls in large-scale commercial structures.

Description

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A load-bearing wall or bearing wall is a wall that is an active structural element of a building — that is, it bears the weight of the elements above said wall, resting upon it by conducting its weight to a foundation structure.[1] The materials most often used to construct load-bearing walls in large buildings are concrete, block, or brick. By contrast, a curtain wall provides no significant structural support beyond what is necessary to bear its own materials or conduct such loads to a bearing wall.[2]

History

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Load-bearing walls are one of the earliest forms of construction.[3] The development of the flying buttress in Gothic architecture allowed structures to maintain an open interior space, transferring more weight to the buttresses instead of to central bearing walls. The Notre Dame Cathedral is an example of a load-bearing wall structure with flying buttresses.[4]

Application

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Depending on the type of building and the number of floors, load-bearing walls are gauged to the appropriate thickness to carry the weight above them. Without doing so, it is possible that an outer wall could become unstable if the load exceeds the strength of the material used, potentially leading to the collapse of the structure. The primary function of this wall is to enclose or divide space of the building to make it more functional and useful. It provides privacy, affords security, and gives protection against heat, cold, sun or rain.[5]

Housing

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In housing, load-bearing walls are most common in the light construction method known as "platform framing", and each load-bearing wall sits on a wall sill plate which is mated to the lowest base plate. The sills are bolted to the masonry or concrete foundation.[6]

A beam of PSL lumber installed to replace a load-bearing wall at the first floor of a three-story building.

The top plate or ceiling plate is the top of the wall, which sits just below the platform of the next floor (at the ceiling). The base plate or floor plate is the bottom attachment point for the wall studs. Using a top plate and a bottom plate, a wall can be constructed while it lies on its side, allowing for end-nailing of the studs between two plates, and then the finished wall can be tipped up vertically into place atop the wall sill; this not only improves accuracy and shortens construction time, but also produces a stronger wall.

Skyscrapers

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The Chicago Willis Tower uses a bundle of tube structures which, in turn, include numerous outer wall columns.

Due to the immense weight of skyscrapers, the base and walls of the lower floors must be extremely strong. Pilings are used to anchor the building to the bedrock underground. For example, the Burj Khalifa, the world's tallest building as well as the world's tallest structure, uses specially treated and mixed reinforced concrete. Over 45,000 cubic metres (59,000 cu yd) of concrete, weighing more than 110,000 t (120,000 short tons) were used to construct the concrete and steel foundation, which features 192 piles, with each pile being 1.5 m diameter × 43 m long (4.9 ft × 141 ft) and buried more than 50 m (160 ft) deep.[7]

See also

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  • Column – in most larger, multi-storey buildings, vertical loads are primarily borne by columns / pillars instead of structural walls
  • Tube frame structure – Some of the world's tallest skyscrapers use load-bearing outer frames – be it single tube (e.g. the old WTC Twin Towers), or bundled tube (e.g. the Willis Tower or the Burj Khalifa)

References

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  1. ^ "How to Identify a Load-Bearing Wall". Lifehacker. Retrieved 2020-06-26.
  2. ^ "Load-bearing wall". www.designingbuildings.co.uk. Retrieved 2020-06-26.
  3. ^ Montaner, Carme (2021-03-31). "8º Simposio Iberoamericano de Historia de la Cartografía. El mapa como elemento de conexión cultural entre América y Europa. Barcelona, 21 y 22 de octubre del 2020". Investigaciones Geográficas (104). doi:10.14350/rig.60378. ISSN 2448-7279. S2CID 233611245.
  4. ^ Mendes, Gilmar de Melo (2012). El equilibrio de la arquitectura organizativa desde el enfoque de agencia: estudio de un caso (Thesis). Universidad de Valladolid. doi:10.35376/10324/921.
  5. ^ "7 FUNCTIONAL REQUIREMENTS A BUILDING WALL SHOULD SATISFY". CivilBlog.Org. 2015-07-08. Retrieved 2020-05-31.
  6. ^ "What is Platform Framing? (with pictures)". wiseGEEK. Retrieved 2020-06-26.
  7. ^ "Burj Khalifa, Dubai | 182168". Emporis. Archived from the original on August 5, 2011. Retrieved 2018-09-17.
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Jeffery James

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

Sarah McNeily

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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

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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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