Effective construction cost estimating is both a science and an art. The science of estimating involves the correct application of proper mathematical principles in calculating material and labor quantities, whereas, the art of estimating involves the subjective part of an estimate. Elements such as the productivity of the labor force can have a huge impact on construction cost. Even on projects that appear similar, many factors of the human equation can affect the productivity of a worker. The effective estimator will apply some measure of art to the scientifically calculated quantities.

Recommended steps to effectively plan an estimate include estimating systematically, estimating the same each time, following the construction sequence, and controlling your environment. The discussion will begin with estimating systemically.

Estimating Systematically

Estimating systematically means to establish some form of system when preparing the estimate. The system could consist of many parts. For example, one part of the system when doing a lineal feet of wall could include the physical way of completing the takeoff. The estimator could start at the top left corner of the document and complete the takeoff measuring all horizontal walls moving towards the right and bottom of the page, marking off each horizontal wall as it is counted. Next, the vertical walls could be counted using the same pattern. Another part of the system could be to use colored markers or pencils to mark off each element as it is counted, with a specific color representing a specific construction element.

An additional part of the system could include identifying each type of quantity that is to be calculated. For example, concrete footing could be calculated using a cubic yard quantity or a lineal foot quantity. Either one could be correct depending upon the need in the estimate. The key would be to determine which method is appropriate for which instance and to systematically apply the appropriate system in the correct instance. Another aspect of estimating systematically could include monitoring and updating the system as the need arises.

Estimate the Same Each Time

Estimating the same each time is closely related to estimating systematically but might include additional elements such as measuring to specific parts of the element. For example, when calculating lineal feet of wall, the length could be determined by measuring from the center line to the center line of walls. It could also be calculated by measuring to one side of the wall. Where there are corners or intersections, the corners could be counted a single time, or they could be double counted. Again, either way could be appropriate depending on the circumstances.

Following the Construction Sequence

It is generally recommended that estimates be prepared in the order of the construction sequence. This helps in the mental process of building the project in your mind. In addition, it provides the opportunity to identify challenges and obstacles that elements installed early in the construction process might cause for elements that are installed at a later time.

Control Your Environment

Estimating is a difficult mental process. It takes work and concentration to visualize in the mind the construction process. Failing to control the environment can lead to a break in concentration which can lead to errors or omissions in preparing the estimate. A few of the principles that go into controlling your environment could include laying out the room to your advantage, working without interference, and confining phone calls to outgoing calls.

Layout the Room to Your Advantage

The room where the estimate is made should be set up to aid in the estimating process. When working with paper plans, there should be a table sufficiently large to allow the plans to lay flat and easily turn the pages. Supplementary materials such as reference materials, catalogs, estimating tables, and price lists should be easily available without having to waste time searching for them.

Computers should be comfortable and convenient to use. Large monitors and multiple screens can be an asset, especially when graphic or computerized takeoff programs such as On Screen Takeoff or Bluebeam are used. Computer files should be structured and set up to aid in the estimating process and allow for easy access of information and materials.

Other aides such as pencils and markers should be easily accessible and easy to use.

Confine Phone Calls

Phone calls should be limited to those which pertain to the current estimate to not cause distractions.

Work Without Interference

Interruptions can cause significant wasted time and can result in mistakes that can cost thousands of dollars.

Steps in the Estimating Process

Important steps in the estimating process include making a job site visit, plan review, developing a mental visualization of the job, and contingency planning.

Job Site Visit

One important activity of planning the estimating process is to make a visit to the job site. Even if there are adequate plans and specifications, additional essential information can be obtained during a job site visit. Often that information cannot be determined in any other way. Items to include in a checklist of a job site visit should include the following:

Utilities

One of the first things to check on a job site visit is the public and private utility locations on the site. These services include electrical power, sewer and water, fuel gas, telephone, television, and computer internet.

Electrical Power Supply

Information about the location and condition of the electrical power supply is essential. Power may be supplied either overhead or underground. In addition to the permanent power supply for the finished project, temporary power will also need to be supplied during the construction process and some procedures made for the transition from temporary power to permanent power at a point in the process.

Questions such as where will the temporary power pole be set if needed? Who will supply and install it, the contractor or the power company? Where will the power meter be located and where will power enter the home?

Sewer and Water Supply

Construction projects also have needs for both temporary and permanent water supply. The source of the water and sewer should be determined. Will it be supplied using public utilities or do well and septic systems need to be installed? Where will the sewer and water enter the house?

Public utility water and sewer main lines typically are run on one side of the street or alley. If the supply lines are located on the opposite side of the street, plans will need to be made for either excavating the street or drilling under the street.

The depth of sewer and water lines will also need to be determined particularly if the structure includes a basement. Public sewer lines may not be deep enough to allow for basement bathroom fixtures without the additional installation of a separate sewage pump. The same is also likely true with septic systems as many public health utilities only allow for shallow septic systems installations.

Fuel Gas Supply

Many construction projects also have a requirement for fuel gas supply. The fuel gas may be either natural gas which is supplied through a network of underground supply lines, or propane which usually has a supply tank located on the site with underground lines running from the tank to the appliances. Natural gas supply lines may also be run on a single side of the street. The placement of the gas meter or propane tank will need to be determined, and the location where the gas will enter the structure will also need to be established.

Telephone, Television, and Computer

Utilities can also include other electrical and electronic transmission facilities such as telephones, television, and computer internet networks. Transmission supply for these utilities can also be located above or underground. Satellite systems and receivers may also need to be installed.

Job Site Logistics

Job site logistics include essentials such as the access to the job site, trash management, sanitation, and job site security.

Job Site Access

Provisions will need to be made for access of construction materials and equipment during the building process. There may need to be places for laydown and storage of supplies delivered to the job. The unloading, placement, and workspace of construction equipment also need to be considered.

Some building lots may be small, tight, or steeply sloped making it difficult to access all sides of the building. Concrete may need to be pumped and other special arrangements made.

Trash Management

Arrangement will need to be made on most construction projects for the removal of trash and construction waste. Determinations will need to be made such as who will be responsible for the removal of waste. Will individual subcontractors be required to remove their own waste, or will facilities be provided for the joint removal of all waste? Will a waste dumpster be provided on the jobsite and, if so, where will the dumpster be located? Some municipalities do not allow the placement of dumpsters on public streets. In addition, large roll-off dumpsters require a significant amount of space above the dumpster to allow it to be winched up onto the flatbed of the dump truck. Overhead utility lines can interfere with this which could limit the placement of the dumpster.

Sanitation

Sanitation facilities such as portable toilets may be required on the job site. Determination will need to be made as to what the needs and requirements are. Placement of any portable toilet facilities will also need to be determined. As is the case with dumpsters, some municipalities may not allow for the placement of temporary sanitation facilities on public streets.

Site Conditions

Site conditions include elements of site use and planning such as soil conditions and type, site elevations, storm water requirements, zoning requirements, and deed and restrictive covenants.

Soil Conditions and Type

Visiting the site can provide valuable information about soil conditions at the site and whether further study is needed. The visit should be used to determine as much as possible about the soil conditions. What type of soil is it? Could it be gravel that will require shoring the excavation? There may be expansive clay conditions that would require additional excavation and fill before placing exterior concrete flatwork. Does the topsoil need to be stripped and can it be stored on site, or will it need to be hauled away? Is the topsoil suitable for landscape planting, or will additional topsoil need to be brought in?

Site Elevations

Site elevation considerations to take into account include the shape and contour of the building lot. Is it conducive to the style and shape of home to be built? What is the present grade of the lot, and will significant changes to the grade need to be made? What is the final grade of the lot? What is the drainage of the lot, and will there need to be accommodations for stormwater control?

Stormwater Requirements

The Environmental Protection Agency requires a Stormwater Pollution and Prevention Plan (SWPPP) to be submitted on building sites one acre or larger. The SWPPP plan requires the builder to control the drainage of all stormwater on the site and to prevent the silt from excavation from leaching off of the site. The SWPPP plan may require the installation of stormwater control features such as silt fences, drainage mats, and hay bales.

Zoning

Most municipalities have zoning requirements and restrictions. Zoning restrictions may limit the use, size, and type of possible construction within the zoned area. Zoning also usually requires specific setbacks for the front, rear, and sides of the property. It is important to determine if the structure fits within the zoning setback restrictions of the property.

Deed and Restrictive Covenants

In addition to zoning requirements, property may have specific deed and restrictive covenants attached to it. These may further specify the details of construction and can, at times, be very restrictive.

Plan Review

The second step in the estimate planning process includes a plan and specification review. The estimator should review the plans in detail and begin building the plans within their mind. Check the plans and the specific details of the plans and look for any discrepancies. Do the same with the specifications, and make sure that all the details are understood. See that the plans reflect all of the conditions found on the site visit.

How were the plans obtained? Were they supplied by the architect? Were they supplied by the customer, or were they purchased from a plan service? Each of these choices have different ramifications for the construction process. Make sure that all of the changes requested by the owner have been incorporated into the plans. Check to see if the plans meet the local building code. In addition, make sure that you are familiar with the building method used.

Mental Visualization of the Job

During the plan review process, begin the process of building the project in your mind. Focus on how the job will be built and what procedures will be used. What sequence will be followed during the construction process? Identify any nonstandard construction processes that the project will involve.

Use this time to develop questions for the architect and owner. Identify any code clarifications that might be needed and any special requirements for the project.

Contingency Planning

Contingency planning is making plans and preparations to account for unexpected or unforeseen circumstances. This is not the same as just adding amounts to the estimate in case something was forgotten and doesn’t take the place of careful and thoughtful estimating. However, careful and thoughtful planning does include considering possible unexpected outcomes and making contingencies for those outcomes if it seems like the situation warrants it. Some possible areas where contingency planning might be justified could include labor and subcontractors, weather, inflation, and the owner.

Labor and Subcontractors

Labor situations in construction can, on occasion, be volatile, especially during times of high economic growth which can fuel an increase in quantity and size of construction projects. This can lead to shortages of construction craft, subcontractor labor, and increases in wage cost. In addition, the schedule of a project may be slowed down as labor becomes available or needs to be trained.

Weather

The weather can have a significant effect on construction planning and costs. Building in cold climates may require arrangement for temporary heat in the building or for elements of the building to be tented and heated. In addition, workers generally require more time and energy when working in cold conditions. Hot weather can also have a significant effect on building. For example, roofers may not be able to install roofing shingles on a roof during the heat of the day because of damage that can occur from walking on the hot shingles. Rain or other weather factors can also significantly delay the project. These possibilities should be considered when undertaking and planning an estimate.

Inflation

The construction industry can be a very volatile business and is very sensitive to inflationary pressures, both positive and negative. From 2003 to 2005, residential inflation increased at a rate of 10% per year and the years 2007 until 2011 experienced a 17% deflation over the four-year period. New residential construction again returned to an inflationary cycle from 2013 to 2017 that averaged 6% per year (2). Planning for such volatile cycles can be challenging, especially on construction projects that can span multiple years. The current economic climate does need to be considered when planning an estimate. Questions to consider include whether lumber prices are rising or falling and if construction labor costs are rising or falling. If the situation warrants it, contingencies may need to be included in the estimate. Current inflation trends can easily be found from a number of sources, including government and private sources such as the National Association of Home Builders.

The Owner

A construction contractor once wrote:

“Working for nice people virtually eliminates bad debt, boosts crew morale, reduces callbacks, and improves referrals. You sleep better at night and have an easier time coming to work Monday mornings, and so do the people you work with…. What we can’t do is make a chronically angry, resentful person happy with our work no matter how hard we try. We can’t make an irrevocably untrusting soul feel comfortable letting us in his house. We can’t (and shouldn’t) adjust our prices sufficiently to satisfy a stubborn tightwad.”

Journal of Light Construction, Paul Eldrenkamp, December 2001

All construction projects ultimately have an owner. If the owner is known at the time that the estimate is prepared, it would be appropriate to include in the contingency planning any additional costs that could be incurred as a result of working with a difficult owner. As the previous article mentions, some owners can be easy to deal with and others less so. There is a real cost involved in working with difficult owners. Part of contingency planning should include evaluating the requirements and temperament of the owner.

CITATIONS:

Eldrenkamp, P. (2001). Journal of Light Construction, (December).

https://www.fgould.com/americas/articles/cost-estimating-art-science-or-both/

http://maxpixel.freegreatpicture.com/Architecture-Architectural-Drawing-Plans-Drawing-2284505

Sony IIce-6000. (n.d.). Architecture Architectural Drawing Plans Drawing. Retrieved May 7, 2018, from

Sundaram, R. (2015, August 20). Cost Estimating - Art, Science or Both? Retrieved May 8, 2018, from