Clarifying the Expense of Permits and Administrative Tasks

Clarifying the Expense of Permits and Administrative Tasks

Tips for communicating effectively with clients about follow up plans and expectations

Overview of common permits required for foundation repair projects


When embarking on a foundation repair project, understanding the permits and administrative tasks required is crucial for ensuring the work is done legally and safely. Discussing financing options helps homeowners budget for foundation repair service foundation repair service market wall. Here's an overview of common permits you might need:

1. **Building Permit**: This is the most fundamental permit required for any structural work, including foundation repairs. It ensures that the work meets local building codes and standards. Applying for a building permit usually involves submitting detailed plans and specifications of the proposed work.

2. **Excavation Permit**: If your foundation repair involves digging, you'll likely need an excavation permit. This permit is crucial for ensuring that the excavation work does not damage utility lines or affect the stability of neighboring properties. It often requires coordination with local utility companies to mark underground services.

3. **Environmental Permit**: In some cases, especially if the foundation repair involves contaminants or impacts local waterways, an environmental permit may be necessary. This ensures that the work complies with environmental regulations and does not harm the local ecosystem.

4. **Demolition Permit**: If part of the foundation needs to be removed, a demolition permit is required. This permit ensures that the demolition is carried out safely and that debris is properly managed.

5. **Occupancy Permit**: After the foundation repair is complete, an occupancy permit may be required to confirm that the structure is safe for use. This usually involves a final inspection by a building official to ensure all work meets code requirements.

Navigating these permits can be complex, but they are essential for ensuring the safety and legality of your foundation repair project. It's advisable to consult with local building authorities early in the process to understand all requirements and avoid delays.

Detailed explanation of the costs associated with obtaining permits for foundation repair


Certainly! When it comes to foundation repair, one aspect that often catches homeowners off guard is the cost associated with obtaining permits. Understanding these expenses is crucial for budgeting and ensuring that the repair process goes smoothly.

Firstly, let's break down what these permits actually are. Essentially, a permit is an official document issued by local government authorities that allows you to proceed with construction or repair work. In the case of foundation repair, this is vital because it ensures that the work is done in compliance with local building codes and safety standards.

The cost of these permits can vary widely depending on several factors. One major factor is the location. Different cities and municipalities have their own set of rules and fee structures. For instance, obtaining a permit in a bustling urban area might be more expensive than in a smaller, rural town due to higher administrative costs and more stringent regulations.

Another factor influencing the cost is the scope of the repair work. If the foundation repair is extensive and involves significant modifications to the structure, the permit fees will likely be higher. This is because more complex projects require more thorough inspections and oversight to ensure safety and compliance.

Additionally, the type of foundation being repaired can impact permit costs. Whether it's a concrete slab, crawl space, or pier and beam foundation, each type may have different regulatory requirements, thus affecting the permit fees.

It's also important to consider the administrative tasks that come along with obtaining these permits. This includes submitting detailed plans and specifications, attending meetings with local officials, and possibly even hiring a professional engineer to ensure that your repair plans meet all necessary codes. These tasks can add to the overall cost, as they require time and often professional expertise.

In some cases, there might be additional fees for expedited processing if you need the permit quickly. While this can be convenient, it's an extra cost to keep in mind.

To sum it up, the costs associated with obtaining permits for foundation repair are multifaceted. They depend on your location, the scope and type of repair, and the administrative efforts required. Being aware of these factors can help you better prepare financially and avoid any surprises down the line. Always remember to budget for these permits as an essential part of your foundation repair expenses.

Discussion on the administrative tasks involved in foundation repair services and their associated expenses


When it comes to foundation repair services, understanding the administrative tasks and associated expenses is crucial for both service providers and clients. Let's delve into some key aspects of this topic, with a focus on clarifying the expense of permits and administrative tasks.

Firstly, obtaining permits is often a mandatory step in the foundation repair process. These permits ensure that the work being done complies with local building codes and regulations. The cost of permits can vary significantly depending on the location and the scope of the repair work. Typically, these fees are based on a percentage of the total project cost, which can range from 1% to 3%. For a large-scale foundation repair, this might translate into a substantial fee. Additionally, there may be specific fees for inspections, which are necessary to ensure that the work meets safety and quality standards.

Beyond permits, there are other administrative tasks that contribute to the overall expense of foundation repair services. These tasks include project management, scheduling, and coordination with various stakeholders such as contractors, engineers, and local authorities. Effective project management is essential to keep the project on track and within budget. This often involves detailed planning, regular communication, and problem-solving to address any unforeseen challenges that may arise.

Moreover, documentation is a critical administrative task that cannot be overlooked. This includes keeping detailed records of all work performed, materials used, and any changes made to the original plan. Proper documentation not only ensures transparency and accountability but also protects both the service provider and the client in case of any disputes or legal issues.

Another significant administrative expense is insurance. Foundation repair companies must carry various types of insurance, including liability insurance, workers' compensation, and equipment insurance. These insurance policies protect the company from financial loss in case of accidents, injuries, or damage to property. The cost of insurance can be substantial, but it is a necessary investment to safeguard the business and its clients.

Lastly, marketing and customer service are administrative tasks that, while not directly related to the physical repair work, are essential for the success of a foundation repair service. Effective marketing helps attract new clients, while excellent customer service ensures client satisfaction and repeat business. These tasks require time, effort, and often financial investment in advertising, training, and customer relationship management systems.

In conclusion, the administrative tasks involved in foundation repair services, particularly obtaining permits and managing various administrative expenses, play a vital role in the overall cost and success of the project. Understanding these costs helps clients make informed decisions and ensures that service providers can deliver high-quality work efficiently and effectively.

Analysis of how different regions and municipalities impact the cost of permits and administrative tasks


When it comes to understanding the expense of permits and administrative tasks, it's crucial to consider the significant impact that different regions and municipalities have on these costs. Each locality sets its own regulations, fees, and processes, which can lead to a wide range of expenses for individuals and businesses alike.

Firstly, urban areas often have higher costs for permits and administrative tasks due to the greater demand for services and the complexity of infrastructure. In cities, the need for permits is usually more stringent because of higher population densities, more stringent zoning laws, and the necessity to maintain orderly development. For instance, building a new structure in a bustling metropolitan area might require various permits for construction, environmental impact, and zoning compliance, each with its associated fee.

Conversely, rural areas may have lower costs but could present different challenges. The administrative processes in these regions might be less streamlined, leading to longer wait times and potentially higher indirect costs, such as lost time and productivity. Additionally, rural municipalities might have fewer resources to dedicate to permit processing, which can result in delays and frustrations for applicants.

State and local governments also play a pivotal role in shaping these costs. Some states implement uniform fee structures across municipalities to promote fairness and transparency. Others allow each municipality to set its own fees, leading to a patchwork of costs that can be confusing and burdensome for those navigating multiple jurisdictions.

Moreover, economic conditions within a region can influence permit costs. In areas experiencing a construction boom, local governments might increase fees to manage the influx of applications and to fund infrastructure improvements. Conversely, in economically depressed areas, fees might be lower to encourage development and investment.

In summary, the cost of permits and administrative tasks is deeply influenced by the specific region and municipality in which they are required. Understanding these variations is essential for anyone looking to navigate the often complex and costly landscape of permits and administrative procedures. Whether in a thriving city or a quiet rural town, being aware of local regulations and fee structures can help mitigate expenses and streamline the process.

Strategies for homeowners to manage and minimize expenses related to permits and administrative tasks


Certainly! Managing and minimizing expenses related to permits and administrative tasks can be a bit of a challenge for homeowners, but with some smart strategies, it's definitely doable. Here are a few practical tips to help you navigate this terrain more effectively.

First off, it's crucial to do your homework. Before you even think about picking up the phone to call the local building department, take some time to research. Look into what types of permits you might need for your project. Different projects require different permits, and some might not need any at all. Understanding this from the get-go can save you a lot of time and money.

Next, consider timing. Believe it or not, the time of year can affect the cost and processing time of permits. During peak construction seasons, departments can be overwhelmed, leading to longer wait times and potentially higher fees due to increased demand. If your project allows for flexibility, try to plan your permit applications during off-peak times. This not only might reduce costs but can also get your project moving faster.

Another strategy is to bundle your permits. If your home improvement project requires multiple permits, see if you can apply for them all at once. Some local governments offer discounts for bundled applications, which can significantly reduce your overall expenses.

Don't forget about the value of professional advice. While it might seem counterintuitive to spend money to save money, hiring a professional consultant who understands the ins and outs of local permitting processes can pay off in the long run. They can help you navigate the complexities, ensure you're not overlooking any necessary permits, and might even know about discounts or fee waivers you're eligible for.

Lastly, keep organized records of all your communications and documentation related to permits and administrative tasks. This not only makes the process smoother but can also be invaluable if you encounter any issues or need to appeal a decision. Being well-organized can prevent costly mistakes and misunderstandings.

In conclusion, managing and minimizing expenses related to permits and administrative tasks requires a bit of planning, research, and sometimes, professional guidance. But with these strategies in mind, homeowners can navigate the permitting process more efficiently, saving both time and money in the process.

Case studies highlighting the expense of permits and administrative tasks in various residential foundation repair projects


When it comes to residential foundation repair projects, the expense of permits and administrative tasks can significantly impact the overall budget. Through various case studies, we can gain a clearer understanding of these costs and their implications.

In one suburban neighborhood, a homeowner faced extensive foundation issues due to soil expansion. Initially, the repair estimate seemed manageable, but the requirement for multiple permits added an unexpected layer of expense. The homeowner had to secure permits for excavation, structural modifications, and environmental impact assessments. Each permit came with its own set of fees and processing times, delaying the project and increasing costs. Ultimately, the administrative tasks accounted for nearly 20% of the total project expense, highlighting the importance of budgeting for such contingencies.

Another case involved a historic home where foundation repair was necessary to preserve its structural integrity. Given the home's historical status, additional permits were required from both local and state preservation boards. The homeowner not only had to navigate complex regulatory landscapes but also incur costs for consultation with preservation experts. The administrative burden was further compounded by the need for frequent status updates and compliance checks. In this instance, the permit and administrative costs escalated the project budget by approximately 25%, underscoring the necessity for thorough planning and financial preparation.

In a third example, a multi-family residential building underwent foundation repair to address settling issues. The project required coordination among multiple tenants and property management, adding another layer of complexity. Permit fees for load-bearing wall modifications, as well as administrative costs for tenant notifications and temporary relocations, significantly increased the overall expense. The project's timeline was extended due to bureaucratic delays, leading to additional labor costs. This case study illustrates how administrative tasks can ripple through a project, affecting both time and money.

These case studies collectively reveal that the expense of permits and administrative tasks in residential foundation repair projects cannot be overlooked. Homeowners and contractors alike must account for these costs to avoid budget overruns and project delays. By understanding the multifaceted nature of these expenses, stakeholders can better navigate the complexities of foundation repair, ensuring a smoother and more cost-effective process.



Various examples of ornate ceilings

A ceiling /ˈsiːlɪŋ/ is an overhead interior roof that covers the upper limits of a room. It is not generally considered a structural element, but a finished surface concealing the underside of the roof structure or the floor of a story above. Ceilings can be decorated to taste, and there are many examples of frescoes and artwork on ceilings, especially within religious buildings. A ceiling can also be the upper limit of a tunnel.

The most common type of ceiling is the dropped ceiling,[citation needed] which is suspended from structural elements above. Panels of drywall are fastened either directly to the ceiling joists or to a few layers of moisture-proof plywood which are then attached to the joists. Pipework or ducts can be run in the gap above the ceiling, and insulation and fireproofing material can be placed here. Alternatively, ceilings may be spray painted instead, leaving the pipework and ducts exposed but painted, and using spray foam.

A subset of the dropped ceiling is the suspended ceiling, wherein a network of aluminum struts, as opposed to drywall, are attached to the joists, forming a series of rectangular spaces. Individual pieces of cardboard are then placed inside the bottom of those spaces so that the outer side of the cardboard, interspersed with aluminum rails, is seen as the ceiling from below. This makes it relatively easy to repair the pipes and insulation behind the ceiling, since all that is necessary is to lift off the cardboard, rather than digging through the drywall and then replacing it.

Other types of ceiling include the cathedral ceiling, the concave or barrel-shaped ceiling, the stretched ceiling and the coffered ceiling. Coving often links the ceiling to the surrounding walls. Ceilings can play a part in reducing fire hazard, and a system is available for rating the fire resistance of dropped ceilings.

Types

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California tract home with an open-beam ceiling, 1960

Ceilings are classified according to their appearance or construction. A cathedral ceiling is any tall ceiling area similar to those in a church. A dropped ceiling is one in which the finished surface is constructed anywhere from a few inches or centimeters to several feet or a few meters below the structure above it. This may be done for aesthetic purposes, such as achieving a desirable ceiling height; or practical purposes such as acoustic damping or providing a space for HVAC or piping. An inverse of this would be a raised floor. A concave or barrel-shaped ceiling is curved or rounded upward, usually for visual or acoustical value, while a coffered ceiling is divided into a grid of recessed square or octagonal panels, also called a "lacunar ceiling". A cove ceiling uses a curved plaster transition between wall and ceiling; it is named for cove molding, a molding with a concave curve.[1] A stretched ceiling (or stretch ceiling) uses a number of individual panels using material such as PVC fixed to a perimeter rail.[2]

Elements

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Ceilings have frequently been decorated with fresco painting, mosaic tiles and other surface treatments. While hard to execute (at least in place) a decorated ceiling has the advantage that it is largely protected from damage by fingers and dust. In the past, however, this was more than compensated for by the damage from smoke from candles or a fireplace. Many historic buildings have celebrated ceilings. Perhaps the most famous is the Sistine Chapel ceiling by Michelangelo.

Ceiling height, particularly in the case of low ceilings, may have psychological impacts. [3]

Fire-resistance rated ceilings

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The most common ceiling that contributes to fire-resistance ratings in commercial and residential construction is the dropped ceiling. In the case of a dropped ceiling, the rating is achieved by the entire system, which is both the structure above, from which the ceilings is suspended, which could be a concrete floor or a timber floor, as well as the suspension mechanism and, finally the lowest membrane or dropped ceiling. Between the structure that the dropped ceiling is suspended from and the dropped membrane, such as a T-bar ceiling or a layer of drywall, there is often some room for mechanical and electrical piping, wiring and ducting to run.

An independent ceiling, however, can be constructed such that it has a stand-alone fire-resistance rating. Such systems must be tested without the benefit of being suspended from a slab above in order to prove that the resulting system is capable of holding itself up. This type of ceiling would be installed to protect items above from fire.

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See also

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  • Beam ceiling
  • Hammerbeam roof
  • Hollow-core slab
  • Moulding (decorative)
  • Popcorn ceiling
  • Scottish Renaissance painted ceilings
  • Tin ceiling
  • Passive fire protection
  • Fire test
  • Hy-Rib

References

[edit]
  1. ^ "Casa de las Ratas 2/2/2003". Archived from the original on September 29, 2008. Retrieved September 14, 2008.
  2. ^ Corky Binggeli (2011). Interior Graphic Standards: Student Edition. John Wiley & Sons. p. 220. ISBN 978-1-118-09935-3.
  3. ^ Meyers-Levy, Joan; Zhu, Rui (Juliet) (August 2007). "The Influence of Ceiling Height: The Effect of Priming on the Type of Processing That People Use". Journal of Consumer Research. 34 (2): 174–186. doi:10.1086/519146. JSTOR 10.1086/519146. S2CID 16607244.
  4. ^ Melvin, Jeremy (2006). …isme Să ÎnÈ›elegem Stilurile Arhitecturale (in Romanian). Enciclopedia RAO. p. 39. ISBN 973-717-075-X.
  5. ^ Bresc-Bautier, Geneviève (2008). The Louvre, a Tale of a Palace. Musée du Louvre Éditions. p. 26. ISBN 978-2-7572-0177-0.
  6. ^ Bresc-Bautier, Geneviève (2008). The Louvre, a Tale of a Palace. Musée du Louvre Éditions. p. 30. ISBN 978-2-7572-0177-0.
  7. ^ Bresc-Bautier, Geneviève (2008). The Louvre, a Tale of a Palace. Musée du Louvre Éditions. p. 55. ISBN 978-2-7572-0177-0.
  8. ^ Bresc-Bautier, Geneviève (2008). The Louvre, a Tale of a Palace. Musée du Louvre Éditions. p. 106. ISBN 978-2-7572-0177-0.
  9. ^ Bresc-Bautier, Geneviève (2008). The Louvre, a Tale of a Palace. Musée du Louvre Éditions. p. 138. ISBN 978-2-7572-0177-0.
  10. ^ Marinache, Oana (2015). Ernest Donaud - visul liniei (in Romanian). Editura Istoria Artei. p. 79. ISBN 978-606-94042-8-7.
[edit]
  • Media related to Ceilings at Wikimedia Commons
  • "Ceiling" . Encyclopædia Britannica. Vol. 5 (11th ed.). 1911.
  • "Ceiling" . New International Encyclopedia. 1904.
  • Merriam-Webster ceiling definition

 

 

 

Basement waterproofing involves techniques and materials used to prevent water from penetrating the basement of a house or a building. Waterproofing a basement that is below ground level can require the application of sealant materials, the installation of drains and sump pumps, and more.

Purpose

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Waterproofing is usually required by building codes for structures that are built at or below ground level. Waterproofing and drainage considerations are especially important in cases where ground water is likely to build up in the soil or where there is a high water table.

Water in the soil causes hydrostatic pressure to be exerted underneath basement floors and walls. This hydrostatic pressure can force water in through cracks, which can cause major structural damage as well as mold, decay, and other moisture-related problems.

Methods

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Several measures exist to prevent water from penetrating a basement foundation or to divert water that has penetrated a foundation:

  • French Drain
    French drain
    Interior wall and floor sealers
  • Interior water drainage
  • Exterior drainage
  • Exterior waterproofing coatings
  • Box type waterproofing[1]
  • Foundation crack injections
  • French drains
  • Sump pump

Interior sealants

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In poured concrete foundations, cracks and pipe penetrations are the most common entry points for seepage. These openings can be sealed from the interior. Epoxies, which are strong adhesives, or urethanes can be pressure injected into the openings, thus penetrating the foundation through to the exterior and cutting off the path of the seepage.

In masonry foundations, interior sealers will not provide permanent protection from water infiltration where hydrostatic pressure is present. However, interior sealers are good for preventing high atmospheric humidity inside the basement from absorbing into the porous masonry and causing spalling. Spalling is a condition where constant high humidity or moisture breaks down masonry surfaces, causing deterioration and shedding of the concrete surfaces.

Other coatings can be effective where condensation is the main source of wetness. It is also effective if the problem has minor dampness. Usually, interior waterproofing will not stop major leaks.

Interior water drainage

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Although interior water drainage is not technically waterproofing, it is a widely accepted technique in mitigating basement water and is generally referred to as a basement waterproofing solution. Many interior drainage systems are patented and recognized by Building Officials and Code Administrators(BOCA) as being effective in controlling basement water.

A common system for draining water that has penetrated a basement involves creating a channel around the perimeter of the basement alongside the foundation footers. A French drain, PVC pipe, or other drainage system is installed in the newly made channel. The installed drain is covered with new cement.

The drainage system collects any water entering the basement and drains it to an internally placed sump pump system, which will then pump the water out of the basement. The Federal Emergency Management Agency (FEMA) recommends basement waterproofing with a water alarm and "battery-operated backup pump" as a preventive measure against the high cost of flooding.[2] Wall conduits (such as dimple boards or other membranes) are fastened to the foundation wall and extend over the new drainage to guide any moisture down into the system.

Exterior waterproofing

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Waterproofing a structure from the exterior is the only method the U.S. International Building Code (IBC) recognizes as adequate to prevent structural damage caused by water intrusion.

Waterproofing an existing basement begins with excavating to the bottom sides of the footings. Once excavated, the walls are then power washed and allowed to dry. The dry walls are sealed with a waterproofing membrane,[3] and new drainage tiles (weeping tiles) are placed at the side of the footing.

A French drain, PVC pipe, or other drainage system is installed and water is led further from the basement.

Polymer

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Over the past ten years, polymer-based waterproofing products have been developed. Polymer-based products last for the lifetime of the building and are not affected by soil pH. Polymer-based waterproofing materials can be sprayed directly onto a wall, are very fast curing, and are semi-flexible, allowing for some movement of the substrate.

Causes of water seepage and leaks

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Water seepage in basement and crawl spaces usually occurs over long periods of time and can be caused by numerous factors.

  • Concrete is one of the most commonly used materials in home construction. When pockets of air are not removed during construction, or the mixture is not allowed to cure properly, the concrete can crack, which allows water to force its way through the wall.
  • Foundations (footings) are horizontal pads that define the perimeter of foundation walls. When footings are too narrow or are not laid deep enough, they are susceptible to movement caused by soil erosion.
  • Gutters and downspouts are used to catch rain water as it falls and to discharge it away from houses and buildings. When gutters are clogged or downspouts are broken, rainwater is absorbed by the soil near the foundation, increasing hydrostatic pressure.
  • Weeping tile is a porous plastic drain pipe installed around the perimeter of the house. The main purpose of external weeping tile is preventing water from getting into a basement. However, these pipes can become clogged or damaged, which causes excess water to put pressure on internal walls and basement floors.
  • Water build up inside window wells, after heavy rain or snow, can lead to leaks through basement window seams. Window well covers can be used to prevent water from accumulating in the window well.
  • Ground saturation is another common form of basement leaks. When the footing drain fails the ground around the basement can contain too much water and when the saturation point is met flooding can occur.

Warning signs of water damage

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Signs that water is seeping into a basement or crawlspace often take years to develop and may not be easily visible. Over time, multiple signs of damage may become evident and could lead to structural failure.

  • Cracked walls: Cracks may be horizontal, vertical, diagonal or stair-stepped. Severe pressure or structural damage is evident by widening cracks.
  • Buckling walls: Usually caused by hydrostatic pressure. Walls appear to be bowed inward.
  • Peeling paint: Water seeping through walls may lead to bubbling or peeling paint along basement walls.[4]
  • Efflorescence: White, powdery residue found on basement walls near the floor.
  • Mold: Fungi that usually grow in damp, dark areas and can cause respiratory problems after prolonged exposure.

Foundation crack injections

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Foundation crack injections are used when poured concrete foundations crack, either from settlement or the expansion and contraction of the concrete. Epoxy crack injections are typically used for structural purposes while hydrophobic or hydrophilic polyurethane injections are used to seal cracks to prevent penetration of moisture or water. Concrete is both strong and inexpensive, making it an ideal product in construction. However, concrete is not waterproof.

References

[edit]
  1. ^ Waheed, M. A. (11 July 2014). "Top tips to optimally use conventional waterproofing techniques". Business Standard India. Archived from the original on 5 July 2022. Retrieved 28 May 2021.
  2. ^ "FloodSmart | How to Prepare for a Flood and Minimize Losses". Archived from the original on 9 May 2020. Retrieved 20 March 2020.
  3. ^ Carter, Tim. "How to redirect water around a damp garage". The Washington Post. Archived from the original on 15 August 2016. Retrieved 2 November 2015.
  4. ^ Chodorov, Jill. "Basement flooding may put a damper on your home sale". The Washington Post. Archived from the original on 18 May 2018. Retrieved 2 November 2015.
Suspended slab under construction, with the formwork still in place
Suspended slab formwork and rebar in place, ready for concrete pour.

A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Steel-reinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ceilings, while thinner mud slabs may be used for exterior paving ( see below).[1][2]

In many domestic and industrial buildings, a thick concrete slab supported on foundations or directly on the subsoil, is used to construct the ground floor. These slabs are generally classified as ground-bearing or suspended. A slab is ground-bearing if it rests directly on the foundation, otherwise the slab is suspended.[3] For multi-story buildings, there are several common slab designs (

see § Design for more types):

  • Beam and block, also referred to as rib and block, is mostly used in residential and industrial applications. This slab type is made up of pre-stressed beams and hollow blocks and are temporarily propped until set, typically after 21 days.[4]
  • A hollow core slab which is precast and installed on site with a crane
  • In high rise buildings and skyscrapers, thinner, pre-cast concrete slabs are slung between the steel frames to form the floors and ceilings on each level. Cast in-situ slabs are used in high rise buildings and large shopping complexes as well as houses. These in-situ slabs are cast on site using shutters and reinforced steel.

On technical drawings, reinforced concrete slabs are often abbreviated to "r.c.c. slab" or simply "r.c.". Calculations and drawings are often done by structural engineers in CAD software.

Thermal performance

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Energy efficiency has become a primary concern for the construction of new buildings, and the prevalence of concrete slabs calls for careful consideration of its thermal properties in order to minimise wasted energy.[5] Concrete has similar thermal properties to masonry products, in that it has a relatively high thermal mass and is a good conductor of heat.

In some special cases, the thermal properties of concrete have been employed, for example as a heatsink in nuclear power plants or a thermal buffer in industrial freezers.[6]

Thermal conductivity

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Thermal conductivity of a concrete slab indicates the rate of heat transfer through the solid mass by conduction, usually in regard to heat transfer to or from the ground. The coefficient of thermal conductivity, k, is proportional to density of the concrete, among other factors.[5] The primary influences on conductivity are moisture content, type of aggregate, type of cement, constituent proportions, and temperature. These various factors complicate the theoretical evaluation of a k-value, since each component has a different conductivity when isolated, and the position and proportion of each components affects the overall conductivity. To simplify this, particles of aggregate may be considered to be suspended in the homogeneous cement. Campbell-Allen and Thorne (1963) derived a formula for the theoretical thermal conductivity of concrete.[6] In practice this formula is rarely applied, but remains relevant for theoretical use. Subsequently, Valore (1980) developed another formula in terms of overall density.[7] However, this study concerned hollow concrete blocks and its results are unverified for concrete slabs.

The actual value of k varies significantly in practice, and is usually between 0.8 and 2.0 W m−1 K−1.[8] This is relatively high when compared to other materials, for example the conductivity of wood may be as low as 0.04 W m−1 K−1. One way of mitigating the effects of thermal conduction is to introduce insulation (

see § Insulation).

Thermal mass

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The second consideration is the high thermal mass of concrete slabs, which applies similarly to walls and floors, or wherever concrete is used within the thermal envelope. Concrete has a relatively high thermal mass, meaning that it takes a long time to respond to changes in ambient temperature.[9] This is a disadvantage when rooms are heated intermittently and require a quick response, as it takes longer to warm the entire building, including the slab. However, the high thermal mass is an advantage in climates with large daily temperature swings, where the slab acts as a regulator, keeping the building cool by day and warm by night.

Typically concrete slabs perform better than implied by their R-value.[5] The R-value does not consider thermal mass, since it is tested under constant temperature conditions. Thus, when a concrete slab is subjected to fluctuating temperatures, it will respond more slowly to these changes and in many cases increase the efficiency of a building.[5] In reality, there are many factors which contribute to the effect of thermal mass, including the depth and composition of the slab, as well as other properties of the building such as orientation and windows.

Thermal mass is also related to thermal diffusivity, heat capacity and insulation. Concrete has low thermal diffusivity, high heat capacity, and its thermal mass is negatively affected by insulation (e.g. carpet).[5]

Insulation

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Without insulation, concrete slabs cast directly on the ground can cause a significant amount of extraneous energy transfer by conduction, resulting in either lost heat or unwanted heat. In modern construction, concrete slabs are usually cast above a layer of insulation such as expanded polystyrene, and the slab may contain underfloor heating pipes.[10] However, there are still uses for a slab that is not insulated, for example in outbuildings which are not heated or cooled to room temperature (

see § Mud slabs). In these cases, casting the slab directly onto a substrate of aggregate will maintain the slab near the temperature of the substrate throughout the year, and can prevent both freezing and overheating.

A common type of insulated slab is the beam and block system (mentioned above) which is modified by replacing concrete blocks with expanded polystyrene blocks.[11] This not only allows for better insulation but decreases the weight of slab which has a positive effect on load bearing walls and foundations.

Formwork set for concrete pour.
Concrete poured into formwork. This slab is ground-bearing and reinforced with steel rebar.

Design

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Ground-bearing slabs

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Ground-bearing slabs, also known as "on-ground" or "slab-on-grade", are commonly used for ground floors on domestic and some commercial applications. It is an economical and quick construction method for sites that have non-reactive soil and little slope.[12]

For ground-bearing slabs, it is important to design the slab around the type of soil, since some soils such as clay are too dynamic to support a slab consistently across its entire area. This results in cracking and deformation, potentially leading to structural failure of any members attached to the floor, such as wall studs.[12]

Levelling the site before pouring concrete is an important step, as sloping ground will cause the concrete to cure unevenly and will result in differential expansion. In some cases, a naturally sloping site may be levelled simply by removing soil from the uphill site. If a site has a more significant grade, it may be a candidate for the "cut and fill" method, where soil from the higher ground is removed, and the lower ground is built up with fill.[13]

In addition to filling the downhill side, this area of the slab may be supported on concrete piers which extend into the ground. In this case, the fill material is less important structurally as the dead weight of the slab is supported by the piers. However, the fill material is still necessary to support the curing concrete and its reinforcement.

There are two common methods of filling - controlled fill and rolled fill.[13]

  • Controlled fill: Fill material is compacted in several layers by a vibrating plate or roller. Sand fills areas up to around 800 mm deep, and clay may be used to fill areas up to 400 mm deep. However, clay is much more reactive than sand, so it should be used sparingly and carefully. Clay must be moist during compaction to homogenise it.[13]
  • Rolled fill: Fill is repeatedly compacted by an excavator, but this method of compaction is less effective than a vibrator or roller. Thus, the regulations on maximum depth are typically stricter.

Proper curing of ground-bearing concrete is necessary to obtain adequate strength. Since these slabs are inevitably poured on-site (rather than precast as some suspended slabs are), it can be difficult to control conditions to optimize the curing process. This is usually aided by a membrane, either plastic (temporary) or a liquid compound (permanent).[14]

Ground-bearing slabs are usually supplemented with some form of reinforcement, often steel rebar. However, in some cases such as concrete roads, it is acceptable to use an unreinforced slab if it is adequately engineered (

see below).

Suspended slabs

[edit]

For a suspended slab, there are a number of designs to improve the strength-to-weight ratio. In all cases the top surface remains flat, and the underside is modulated:

  • A corrugated slab is designed when the concrete is poured into a corrugated steel tray, more commonly called decking. This steel tray improves strength of the slab, and prevents the slab from bending under its own weight. The corrugations run in one direction only.
  • A ribbed slab gives considerably more strength in one direction. This is achieved with concrete beams bearing load between piers or columns, and thinner, integral ribs in the perpendicular direction. An analogy in carpentry would be a subfloor of bearers and joists. Ribbed slabs have higher load ratings than corrugated or flat slabs, but are inferior to waffle slabs.[15]
  • A waffle slab gives added strength in both directions using a matrix of recessed segments beneath the slab.[16] This is the same principle used in the ground-bearing version, the waffle slab foundation. Waffle slabs are usually deeper than ribbed slabs of equivalent strength, and are heavier hence require stronger foundations. However, they provide increased mechanical strength in two dimensions, a characteristic important for vibration resistance and soil movement.[17]
The exposed underside of a waffle slab used in a multi-storey building

Unreinforced slabs

[edit]

Unreinforced or "plain"[18] slabs are becoming rare and have limited practical applications, with one exception being the mud slab (

see below). They were once common in the US, but the economic value of reinforced ground-bearing slabs has become more appealing for many engineers.[10] Without reinforcement, the entire load on these slabs is supported by the strength of the concrete, which becomes a vital factor. As a result, any stress induced by a load, static or dynamic, must be within the limit of the concrete's flexural strength to prevent cracking.[19] Since unreinforced concrete is relatively very weak in tension, it is important to consider the effects of tensile stress caused by reactive soil, wind uplift, thermal expansion, and cracking.[20] One of the most common applications for unreinforced slabs is in concrete roads.

Mud slabs

[edit]

Mud slabs, also known as rat slabs, are thinner than the more common suspended or ground-bearing slabs (usually 50 to 150 mm), and usually contain no reinforcement.[21] This makes them economical and easy to install for temporary or low-usage purposes such as subfloors, crawlspaces, pathways, paving, and levelling surfaces.[22] In general, they may be used for any application which requires a flat, clean surface. This includes use as a base or "sub-slab" for a larger structural slab. On uneven or steep surfaces, this preparatory measure is necessary to provide a flat surface on which to install rebar and waterproofing membranes.[10] In this application, a mud slab also prevents the plastic bar chairs from sinking into soft topsoil which can cause spalling due to incomplete coverage of the steel. Sometimes a mud slab may be a substitute for coarse aggregate. Mud slabs typically have a moderately rough surface, finished with a float.[10]

Substrate and rebar prepared for pouring a mud slab

Axes of support

[edit]

One-way slabs

[edit]

A one-way slab has moment-resisting reinforcement only in its short axis, and is used when the moment in the long axis is negligible.[23] Such designs include corrugated slabs and ribbed slabs. Non-reinforced slabs may also be considered one-way if they are supported on only two opposite sides (i.e. they are supported in one axis). A one-way reinforced slab may be stronger than a two-way non-reinforced slab, depending on the type of load.

The calculation of reinforcement requirements for a one-way slab can be extremely tedious and time-consuming, and one can never be completely certain of the best design.[citation needed] Even minor changes to the project can necessitate recalculation of the reinforcement requirements. There are many factors to consider during the structural structure design of one-way slabs, including:

  • Load calculations
  • Bending moment calculation
  • Acceptable depth of flexure and deflection
  • Type and distribution of reinforcing steel

Two-way slabs

[edit]

A two-way slab has moment resisting reinforcement in both directions.[24] This may be implemented due to application requirements such as heavy loading, vibration resistance, clearance below the slab, or other factors. However, an important characteristic governing the requirement of a two-way slab is the ratio of the two horizontal lengths. If where is the short dimension and is the long dimension, then moment in both directions should be considered in design.[25] In other words, if the axial ratio is greater than two, a two-way slab is required.

A non-reinforced slab is two-way if it is supported in both horizontal axes.

Construction

[edit]

A concrete slab may be prefabricated (precast), or constructed on site.

Prefabricated

[edit]

Prefabricated concrete slabs are built in a factory and transported to the site, ready to be lowered into place between steel or concrete beams. They may be pre-stressed (in the factory), post-stressed (on site), or unstressed.[10] It is vital that the wall supporting structure is built to the correct dimensions, or the slabs may not fit.

On-site

[edit]

On-site concrete slabs are built on the building site using formwork, a type of boxing into which the wet concrete is poured. If the slab is to be reinforced, the rebars, or metal bars, are positioned within the formwork before the concrete is poured in.[26] Plastic-tipped metal or plastic bar chairs, are used to hold the rebar away from the bottom and sides of the form-work, so that when the concrete sets it completely envelops the reinforcement. This concept is known as concrete cover. For a ground-bearing slab, the formwork may consist only of side walls pushed into the ground. For a suspended slab, the formwork is shaped like a tray, often supported by a temporary scaffold until the concrete sets.

The formwork is commonly built from wooden planks and boards, plastic, or steel. On commercial building sites, plastic and steel are gaining popularity as they save labour.[27] On low-budget or small-scale jobs, for instance when laying a concrete garden path, wooden planks are very common. After the concrete has set the wood may be removed.

Formwork can also be permanent, and remain in situ post concrete pour. For large slabs or paths that are poured in sections, this permanent formwork can then also act as isolation joints within concrete slabs to reduce the potential for cracking due to concrete expansion or movement.

In some cases formwork is not necessary. For instance, a ground slab surrounded by dense soil, brick or block foundation walls, where the walls act as the sides of the tray and hardcore (rubble) acts as the base.

See also

[edit]
  • Shallow foundation (Commonly used for ground-bearing slabs)
  • Hollow-core slab (Voided slab, one-way spanning)
  • Beam and block (voided slab, one way spanning)
  • Voided biaxial slab (Voided slab, two-way spanning)
  • Formwork
  • Precast concrete
  • Reinforced concrete
  • Rebar
  • Concrete cover

References

[edit]
  1. ^ Garber, G. Design and Construction of Concrete Floors. 2nd ed. Amsterdam: Butterworth-Heinemann, 2006. 47. Print.
  2. ^ Duncan, Chester I. Soils and Foundations for Architects and Engineers. New York: Van Nostrand Reinhold, 1992. 299. Print.
  3. ^ "Ground slabs - Introduction". www.dlsweb.rmit.edu.au. Archived from the original on 2019-11-18. Retrieved 2017-12-07.
  4. ^ "What is a rib and block slab?". www.royalconcreteslabs.co.za. Royal concrete slabs.
  5. ^ a b c d e Cavanaugh, Kevin; et al. (2002). Guide to Thermal Properties of Concrete and Masonry Systems: Reported by ACI Committee 122. American Concrete Institute.
  6. ^ a b Campbell-Allen, D.; Thorne, C.P. (March 1963). "The thermal conductivity of concrete". Magazine of Concrete Research. 15 (43): 39–48. doi:10.1680/macr.1963.15.43.39. UDC 691.32.001:536.21:691.322.
  7. ^ Valore, R.C. Jr. (February 1980). "Calculation of U-values of Hollow Concrete Masonry". Concrete International. 2: 40–63.
  8. ^ Young, Hugh D. (1992). "Table 15.5". University Physics (7th ed.). Addison Wesley. ISBN 0201529815.
  9. ^ Sabnis, Gajanan M.; Juhl, William (2016). "Chapter 4: Sustainability through Thermal Mass of Concrete". Green Building with Concrete: Sustainable Design and Construction (2nd ed.). Taylor & Francis Group. ISBN 978-1-4987-0411-3.
  10. ^ a b c d e Garber, George (2006). Design and Construction of Concrete Floors (2nd ed.). Amsterdam: Butterworth-Heinemann. ISBN 978-0-7506-6656-5.
  11. ^ "What is a polystyrene concrete slab?". www.royalconcreteslabs.co.za. Royal concrete slabs.
  12. ^ a b McKinney, Arthur W.; et al. (2006). Design of Slabs-on-Ground: Reported by ACI Committee 360 (PDF). American Concrete Institute. Archived from the original (PDF) on 2021-05-08. Retrieved 2019-04-04.
  13. ^ a b c Staines, Allan (2014). The Australian House Building Manual. Pinedale Press. pp. 40–41. ISBN 978-1-875217-07-6.
  14. ^ "Concrete in Practice 11 - Curing In-Place Concrete" (PDF). Engineering.com. National Ready Mixed Concrete Association. Archived from the original (PDF) on 4 April 2019. Retrieved 4 April 2019.
  15. ^ "Ribbed Slabs Datasheet" (PDF). Kaset Kalip. Archived from the original (PDF) on 29 March 2018. Retrieved 4 April 2019.
  16. ^ "Ribbed and waffle slabs". www.concretecentre.com. Retrieved 2019-04-04.
  17. ^ Concrete Framed Buildings: A Guide to Design and Construction. MPA The Concrete Centre. 2016. ISBN 978-1-904818-40-3.
  18. ^ Garrison, Tim (19 February 2014). "Clearing the confusion on 'plain concrete'". Civil & Structural Engineer. Archived from the original on 8 May 2019. Retrieved 8 May 2019.
  19. ^ Walker, Wayne. "Reinforcement for slabs on ground". Concrete Construction. Retrieved 8 May 2019.
  20. ^ "Rupture depth of an unreinforced concrete slab on grade" (PDF). Aluminium Association of Florida, Inc. Archived from the original (PDF) on 2020-09-26. Retrieved 2019-05-08.
  21. ^ Arcoma, Peter. "What is a mud slab?". Builder-Questions.com. Retrieved 8 May 2019.
  22. ^ Postma, Mark; et al. "Floor Slabs". Whole Building Design Guide. National Institute of Building Sciences. Retrieved 8 May 2019.
  23. ^ Gilbert, R. I. (1980). UNICIV Report 211 (PDF). University of New South Wales.
  24. ^ Prieto-Portar, L. A. (2008). EGN-5439 The Design of Tall Buildings; Lecture #14: The Design of Reinforced Concrete Slabs (PDF). Archived from the original (PDF) on 2017-08-29. Retrieved 2019-04-04.
  25. ^ "What is the difference between one way and two way slab?". Basic Civil Engineering. 16 June 2019. Retrieved 8 July 2019.
  26. ^ Concrete Basics: A Guide to Concrete Practice (6th ed.). Cement Concrete & Aggregates Australia. 2004. p. 53.
  27. ^ Nemati, Kamran M. (2005). "Temporary Structures: Formwork for Concrete" (PDF). Tokyo Institute of Technology. Archived from the original (PDF) on 12 July 2018. Retrieved 4 April 2019.
[edit]
  • Concrete Basics: A Guide to Concrete Practice
  • Super Insulated Slab Foundations
  • Design of Slabs on Ground Archived 2021-05-08 at the Wayback Machine

 

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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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