While we await the results of the Estimating Survey, which closes February 1, let’s take a look at several actual estimating spreadsheets and see what we can discern as possible best practices. Starting this week, we will be examining estimating templates used by various public agencies and posted on their websites for public use. Links to the actual templates will be included for our readers use. In today's issue, we take a look at the use of multiple sheet “tabs” for organizational purposes.
Three Sheets Every Estimate Should Contain
In a spreadsheet program like Excel, a single spreadsheet file may contain multiple sheets. In Excel, each sheet has a tab to facilitate accessing the sheet. The tabs can be labeled to identify the contents of the sheets, and can even be color coded, hidden and/or protected. For the purpose of a construction estimate, a common practice is to use two or more tabs in a single spreadsheet file to organize different parts of the estimate. In our first sample, from the British Columbia Ministry of Transportation and Infrastructure, there are three tabs:
- Project Worksheet
- Assumptions Worksheet
- Cost Element Worksheet
Let’s take a look at why these three sections represent the three primary tabs every estimate spreadsheet should have.
Project Summary Tab
Every estimate should have a separate tab that serves as an project overview and estimate summary. Information on the summary worksheet should include a project description, location, scope summary, project number, RFP date, RFP number, RFP amendment number, if applicable, bid date/time, owner information, general contractor information if this is a subcontractor estimate, estimate status, person in charge of the estimate, and, of course, the total estimate amount. Depending upon whether the estimate is being prepared by an owner, architect, contractor, construction manager or subcontractor, there will be differing degrees and types of information needed on the summary.
Commentary and Assumptions Tab
This worksheet can serve as both a checklist of things to prepare, perform or consider during the course of developing the estimate. Owners will have a different set of considerations, including property acquisition and design costs, than the contractor bidding on the construction portion of a specific project. Having a template, which can be updated and refined with use, helps develop consistency and completeness in construction estimates, and is the first step in contractors developing their own internal “knowledgebase” for use by other and future employees.
Estimate Details Tab
This worksheet is the workhorse of the estimate. It will include takeoff quantities, unit costs of labor and material, support costs, overhead and profit. In the case of our example, which is set up for an owner, the line-item costs are input as a lump sum (and color coded in blue). Project management, planning and design costs are automatically calculated as a percentage of one or more of the direct costs. This worksheet also includes a column to add a contingency amount for each line item.
Summary
There are a number of other tabs that owners or contractors might consider adding to an estimate; we’ll take a look at those next week. The primary takeaway from today’s article is that development and working with a template for performing an estimate is a best practice, no matter what the title and content of the various worksheets used. Starting each estimate from scratch is a formula for errors and omissions.
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The source of the worksheet reviewed in today's article was found at: http://www.th.gov.bc.ca/publications/planning/estimating/sample%20cost%20estimate%20worksheets%20template.xlsx
In the event the link does not work, a copy can be accessed by clicking here:
