Commercial grading is a very specialized phase of the construction process. Without proper ground preparation, construction results could vary widely from the architectural concept, groundwater may create structural problems, and improper drainage could have negative environmental impacts. It is critical to create and execute the site grading plan professionally and to exact specifications for everything from a parking lot or small restaurant to high-rise office buildings.

What is Site Grading?

Any construction site requires some preparation before building begins, including land leveling and grading activity. Grading consists of sculpting an area of land for the needs of a specific project. The goal of grading is to:

  • Provide the desired aesthetics of the property
  • Ensure proper drainage
  • Comply with zoning and other regulatory restrictions and requirements
  • Establish allowable height and depth of cuts, fills, and swales
  • Protect the environment with consideration for stormwater runoff, potential pollutants, and erosion

Benefits of Construction Grading

Grading and site preparation for construction projects is important not only for the structure being built but for neighboring homes or other buildings. Improper grading can mean water runoff will move toward the building rather than being directed safely away. This can cause structural damage from hydrostatic pressure where water accumulates around or under the foundation. Poor grading can also result in water or pollutants being directed toward other properties, creating liability for the builder or owner of the new facility. Property damage from erosion can also occur. Many planning and zoning jurisdictions require approved grading plans before beginning construction to guard against problems caused by improper grading or lack of compliance with land grading standards.

Types of Grading in Construction

What does grading a lot mean? There are multiple types of grading in construction projects:

  • Landscape grading – undergoing a landscaping project – municipal or commercial – may call for topsoil removal for installing irrigation systems, smoothing areas for planting, and modifying slopes or elevations to improve drainage or create a change in appearance. Landscape grading is often referred to as the process of reshaping a land area to modify water runoff patterns or otherwise alter property elevations. Getting the job done right is important to ensure proper drainage and to achieve the best results.
  • Architectural Grading – changing the contours of a land area for a new home, housing development, or commercial property typically relates to changing the contours of the landscape to accommodate proper drainage, remove undesirable elevations, and prepare foundation areas.
  • Regrading – regrading involves lowering or raising the levels of a land area. This can involve large areas or a small project.
  • Finished Grade – for specific purposes such as gravel roads and earthworks projects, grading extends to include the surface and cover of the finished construction, not just the base. In landscaping projects, finish grading refers to finishing the final contour of the project, shaping the desired area to prepare for planting, seeding, or sodding. Finish grading includes putting the final touches on the grading project. This step provides a smooth surface with the removal of such items as large chunks of soil, rocks, and other undesirable debris.
  • Rough Grading – setting the slope or leveling an area for such projects as landscaping, providing a base for turf development, or resolving drainage issues is termed rough grading. This may include adding, removing, or relocation of topsoil. This stage shapes the ground to the desired basic shape and elevations, creates the desired soil composition, and establishes the drainage flow.
  • Final Grade – to complete the grading process and prepare for the final landscaping or seeding, there is often a need to finish the surface with a material that promotes growth. Final grading construction involves covering the area with a coating of screened topsoil or similar matter to complete the grading project.

Getting Approvals for Grading Projects

In many municipalities or regions, grading plans are required before work can begin, and inspections are required to achieve a passing grade after grading construction. Grading projects are inspected, receiving a certificate of approval so that landscaping or construction can proceed. This approval indicates that the resulting elevations and proper drainage match the original grading plan. Site grading plans contain several critical components for evaluation by planning officials:

  • Lot size and structure coverage percentage – many jurisdictions have requirements for maximum allowable coverage of buildings or other structures. This value gives reviewers an immediate reference to determine if that requirement is being met.
  • Earthwork estimates for cut and fill work – these statistics offer valuable information for how much material will be removed or brought in to accomplish the work.
  • Property lines and any easements present, as well as utility lines.

Grading Techniques and Purposes

Grading is most often accomplished using modern heavy equipment such as excavators and bulldozers for a rough finish. For a smoother finished result, graders may be utilized to produce a finer finish. Experienced engineers understand how land grading techniques will impact the final results. This includes:

  • Meeting the needs and expectations of the client
  • Provide the necessary drainage requirements
  • Comply with all local, state, and federal requirements
  • Consider all environmental concerns

What is the difference between grading and excavation? These terms are sometimes used interchangeably, but there is a distinction. Excavation is usually done in the beginning stages of construction for such tasks as removing soil for swimming pools, creating walkway and sidewalk foundations, and digging trenches or channels for utilities. Grading or leveling typically comes later in the construction process, smoothing surface areas and creating an aesthetic appearance for the property. Excavation is not always necessary for a commercial construction project, with site grading producing the desired preparation.

Why Site Grading is Important for Construction Projects

Site grading for construction projects has several objectives:

Prepare Soil for Structure Foundation

Whether the construction effort is a residential, light commercial, or heavy industrial project, preparing the foundation to support the building properly will prevent structural damage from settling caused by inadequate load-bearing properties. Experienced grading engineers will have comprehensive knowledge of where compacting is necessary to support higher demands for the intended structure, and how runoff water must be controlled with grading.

Assure Proper Drainage

Controlling water flow from rain or other sources is a primary concern when creating a grading plan. Water must be directed such that buildings, other properties, and the environment are all considered in a responsible manner that meets all zoning and ethical requirements.

Create the Landscape Aesthetics Desired

Land leveling and grading will be essential to create the desired architectural image of the finished property. This takes into account elevations and leveling needed for walkways, parking areas, driveways, patios, gardens, and other elements of the site plan.

Site Grading Basics

Before grading can begin, civil engineers will create a comprehensive grading plan, describing in detail the proposed work to be done.

What Does a Grading Plan Show?

Grading plans are complex documents that include a wealth of information for engineers, construction planning, and authorities such as zoning or building commissioners. Anyone taking a look at a grading plan for the first time can be totally baffled by the complexity and the various types of lines, numbers, and arrows. Site grading plans contain a wealth of information related to the site’s current condition and the proposed grading results. This allows examiners to evaluate the plan and either approve, make changes, or deny permits for the work. How Do You Read Construction Grading Plans and Elevations? Following professional standards simplifies the interpretation and reading of grading elevations. Grading plans provide a 3-dimensional depiction of a site, indicated by contour lines that follow the site’s elevations, typically set in 2-foot changes in elevation. Therefore, a grading plan with contour lines farther apart will indicate a gentle slope, while more compacted contour lines reveal a steeper slope. Contour lines presented in dashes indicate the site’s current contours, while solid or bold lines are used to indicate the proposed contours. Other information presented on a grading plan includes “spot elevations” that indicate the relationship to mean sea level – critical in some areas. Here again, existing and proposed values are typically represented with “x,” indicating existing values, and “+” for the proposed position. Grading plans also provide valuable information that about trees, property lines, proposed and existing drainage lines, or other mechanisms. Additional information critical to the grading process is included, such as current underground utilities that need to be considered in grading activity.

Illustrations of Site Grading Plan Examples

Site grading plans will vary somewhat in content, depending on the existing and planned topology, but these examples provide a high-level look at their appearance. Images source: Tranquility Computers A quick look at these examples will demonstrate why an untrained eye can be confused rather than informed by the information contained in such grading plans. Creating and interpreting commercial site grading plans is a skill developed from education and experience.

What Does a Grading Plan Cost?

Both excavation and grading involve the use of heavy equipment and specialized skills in its operation. Creating a comprehensive grading plan is typically done by experienced, certified civil engineers or licensed architects. Most municipalities and many homeowner bylaws require detailed grading plans for approval before work commences, especially for significant projects or those with potential ecological impact. Special considerations will be necessary for areas with unique environmental considerations such as seismic activity, nearby wetlands, water tables, or wildlife habitats. Grading plan costs will vary depending on the scope and lot size addressed in the grading plan. There are additional factors that could also come into play – drainage requirements, neighboring properties, earth composition, underground utilities, and others.

How to Get Started with a Site Grading Plan

Providing an accurate grading plan that optimizes the efficient use of existing materials will save money during the actual grading construction process. Cost-saving methods include utilizing existing soil that is being extracted from one area to fill in others, rather than simply removing materials. This results in less material movement, saving time and expense. Stovall Construction has 50 years of experience in commercial construction and general contracting services. We can help you prepare an efficient site grading plan that saves time and money on your projects. Contact Stovall Construction for more information about your grading projects and commercial construction needs.

Soil Preparation

Preparing Soil for New Sod

There is no better time to enhance a lawn’s ultimate beauty and success than by improving the soil before any planting takes place.

Benefits of Proper and Complete Soil Preparation

  • Improved Uniformity • Increased Density • Faster Recovery
  • Reduced Use of Water, Fertilizer, and Pesticides
  • Reduced Maintenance

QUICK FACTS ABOUT SOIL PREP

Why is good soil important?

For optimum growth, turfgrass needs just four things (in proper balance): sunlight, air, water and nutrients. Reduce any of these, or provide too much of any one and the grass may suffer. In the right proportions, the grass will flourish, providing beauty to the landscape and a clean safe place to play, plus many benefits to the environment. Grass obtains three of the four essential factors (air, water, and nutrients) from the soil, but many soils are less than ideal for growing grass. Some soils contain too much clay and may be very compacted…great for roads, but bad for grass because air and water are not available to the roots. Other soils may have too much sand…beautiful on a beach, but difficult to grow grass because water and nutrients won’t stay in the root zone long enough for the plant to use. Another frequently observed problem with many soils is that its pH (the degree of acidity or alkalinity) is too high or low for optimum growth.

What is the best soil for turfgrass?

Loams, sandy loams and loamy sands, with a pH of 6.0 to 7.0 are the very best soils for producing a beautiful, high-use, low maintenance lawn. Unfortunately, this ideal soil mixture is seldom found on any property after construction.

How deep should the soil be for turfgrass?

The absolute minimum quality soil depth for a care-free lawn is 4 inches. However, for deeper root penetration and the benefits that brings, the accepted standard is 6 inches.

Can soils be improved?

Practically without exception, not only can most soils be improved, they usually need to be improved in order to get the maximum results with only a minimum of ongoing effort. The knowledge of what’s necessary, the amount and availability of materials, and the immediate costs of time and money are the factors that typically deter people from taking the steps necessary to improve the soil. The fact is that failing to improve the soil before planting is only inviting a much greater and continual investment of time and money that will never return its value as fully as good preparation.

Step-By-Step Site Preparation

“The beauty is in the blades, but the ‘action’ is in the roots,” is a good adage to remember when growing grass. Thus, the value of the proper site preparation and soil improvement, before any planting takes place, is that it will be easier for the grass roots to penetrate deeply and evenly. Deep roots will make the lawn more drought resistant, a more efficient water and nutrient user, and more dense as new grass plant shoots emerge. A dense lawn crowds out weeds and better resists insects and disease.

1.

Clear the site of all building materials as well as any buried stumps, rocks, stone or other debris that are larger than 2-3 inches in diameter.

2.

Rough grade the entire area to eliminate any drainage problems on the property. This includes sloping the grade away from the building foundations, eliminating or reducing severe slopes and filling low-lying areas. A tractor mounted blade and/or box are most often used for rough grading, but if the area is small, it can be done with hand tools. The rough grading will probably uncover more debris that should be removed and not buried.

3.

Initial tilling to a depth of at least 4 inches should be completed prior to adding any soil amendments. This will control most annual weeds, alleviate subsoil compaction, permit a bonding of the topsoil to the subsoil, and improve root penetration as well as air exchange and water movement.

4.

Incorporate fully decomposed compost into the topsoil by roto-tilling.Use only a basic manure-based compost (either cattle or dairy) at 3-4 cubic yards of compost per 1000 square feet. You should achieve a total topsoil depth of 4-6 inches. Do not add sand or topsoil to your soil. Sand makes clay harder and adding compost will result in good topsoil.

5.

(optional) Test the soil pH with chemical soil test to determine if any pH correcting materials are required. Acidic soils (pH 6 and below) can be improved with the addition of lime. The type (or source) and total amount of applied lime will be determined by the should be based on the recommendations of a reliable garden center, turf professional or soil scientist. Alkaline soils (pH of 7.5and higher) can be improved with the addition of sulfur or gypsum. As with acidic soil correcting materials, the type and total amount of materials will be determined by the level of the alkalinity and should be based on a professional’s recommendation.

6.

Apply a basic lawn fertilizer to the soil. It is not necessary to rake it in. Use a 20-20-10-3 analysis.

7.

Finish grading the entire site, maintaining the rough grade contours and slopes, with a tractor mounted box blade for large areas or a heavy-duty rake for smaller sites.

8.

(optional) Roll the area with a lawn roller 1/3 full of water to firm and settle the surface. Low spots revealed by this step should be filled to match the surrounding grade surface. We recommend that the area be allowed to settle further with rainfall or by applying irrigation water at very short increments. The site is now ready for turf. With this degree of careful and thoughtful soil and site preparation, the resulting lawn will be absolutely beautiful. It will require less maintenance (smaller quantities of water, fertilizer and pesticides) as it maintains a high degree of density and recovers rapidly from wear.
Reading time: 1 minute Steps in preparation of site for construction works involves geotechnical report, site clearing, excavation, grading and compaction. Steps for construction site preparation are discussed. Contents:

  • Preparing Site for Construction Projects
  • Steps in Preparing Site for Construction Projects
    • Geotechnical Report related to Site Soil Properties
    • Construction Site Clearing and Excavation
    • Grading of Construction Project Site
    • Compaction of Construction Project Site

To construct excellent project, the condition of the project site including subsurface and surface condition must be investigated and assessed thoroughly.
Site assessment may involve determining the present and installation of underground services, specify suitable foundation depend on recommendation of geotechnical report, anticipate the level of ground water, grading amount needed for proper drainage to push water away from the structure, whether the site is difficult to excavate or not, frost penetration depth.
To build the structure as per the design, estimate the excavation volume accurately, and provide suitable drainage, structural elevations and layout must be carried out with substantial precision.

Steps in Preparing Site for Construction Projects

Stages or steps which are needed to undertake to prepare the construction project site are.

  • Geotechnical report related to site soil properties
  • Construction site clearing and excavation
  • Grading of project site
  • Project site compaction

Geotechnical report creates communication between project site condition and design and construction recommendation. Therefore, to understand properties and condition of the soil of the project site, a geotechnical report about the soil of the site is a must.
This report commonly describes soil property and provides necessary recommendation. It is produced based on a series of tests on soil. Type of the structure dictates sampling method, type of test, and number of test required.
After achieving and interpreting test results, type of foundation appropriate for the site, settlements and related recommendations, liquefaction possibilities, slope stability, groundwater level, soil bearing capacity, excavation related hazards, soil strength, soil classification, and many more information are provided in the geotechnical reports.
These invaluable data adequately define the properties of soil and its behavior in the future. If the project site prone to earthquake, then necessary testing and recommendation should be included in the geotechnical report.
Preparing Site for Construction Projects Fig.1: Preparing Site for Construction Projects Borehole Sampling for Geotechnical Report Fig.2: Borehole Sampling for Geotechnical Report

Construction Site Clearing and Excavation

Clearing and excavation is part of the greater job which is carried out in preparing site for construction projects. As shown in Figure-3, trees and all sorts of vegetation on the site are removed at site clearing phase.
After the layout of the structure is set accurately, the excavation work begins and the soil is removed to a required depth in which the foundation of the structure is placed.
There are various types of machinery used to excavate and transport soil at project site. The selection of the type of machinery employed for excavation is based on the soil type, how long is the distance the soil need to be transported, soil site ability to carry load, and site accessibility.
For instance, blasting, drilling, and machinery like boulders, backhoe, shovels, and scooper are involved to excavate and transported blasted and drilled materials when rocks are present at the site. construction-site-clearing-2 Fig.3: Clearing Construction Site Removing Excessive Soil and other Materials from Construction site Fig.4: Removing Excessive Soil and other Materials from Construction site Construction Site Excavation Fig.5: Construction Site Excavation

Grading of Construction Project Site

Grading at constructed site is very crucial to force water away from the structure. International Building Code (IBC 2009), provides necessary recommendation to create proper grading.
The Code states that grade slope should be at least one unit vertical to twenty units horizontal in other words 5% at a distance of 3m measured perpendicular from the wall face.
If a horizontal distance of 3 m is not available due to physical hinders, then other options need to be employed such as swales and impervious surface for which least slope should be 2% if is located within the limit of 3m. The IBC code permit minimum slope of one unit horizontal to forty-eight-unit vertical under certain conditions.
If the construction site is not flat, then suitable cutting and filling need to be carried out and the both cut and fill volume is dictated by the lowest level placement of the structure.
Final settlement of soil should be considered while grading is carried out.

Compaction of Construction Project Site

Soil beneath foundation at site construction must be compacted to the required degree which as per IBC Code is 90% of maximum dry density. Compaction of soil layers which support loads is a must because it decreases settlement and consequently prevents undesired incidents.
Tamping, rolling, and vibration are types of loads employed to compact soil layers. there are several machines used for compaction at construction site such as smooth wheel roller, sheep foot roller, rubber tire, crawler, and tamping plate compactor.
Not only does the compaction of soil improve shear strength but also it declines soil permeability and compressibility. Bad Compaction and Poor Grading led to Cracks in the Building Fig.6: Bad Compaction and Poor Grading led to Cracks in the Building Standard Proctor Test for Soil Compaction Fig.7: Standard Proctor Test for Soil Compaction Optimum moisture content should be provided to obtain target degree of compaction. In this regard, silt and clay are considerably sensitive because improper moisture content lead to fail the process and poor compaction will be achieved which usually is not desirable.
The optimum moisture content and compaction percentage are determined by either standard modified or proctor modified compaction test in laboratory.
Read More:
Methods of Dewatering Excavations at Construction Site
Safety Procedures at Construction Site – Safety Precautions and PPEs
Safety Measures to Prevent Accidents at Building Construction Site


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