Building a new way to estimate

Contractors look for new ways to get accurate takeoffs, analyses

By Bruce Buckley

By definition, estimating isn’t an exact science, but many enterprising build teams are eying opportunities to crunch quantities and costs automatically by using computer models.

Through the rising use of building information modeling, more contractors are searching for new ways to get accurate quantity takeoffs and analyses that will speed the estimating process and reduce administrative costs.

BIM, which at its base level produces 3D design models, has gained momentum in recent years among designers and contractors who see its value in visualization and clash detection.

However, applying BIM to estimating has proven a greater challenge because the longstanding divide between the roles of architects and contractors makes it difficult for team members to share common data, some users say. As a result, contractors often build their own models from scratch rather than relying on design model data for estimating.

Despite the redundancy, some large contractors still see value.

Derek Cunz, director of project development at Minneapolis-based M.A. Mortenson Co., says his company looks to get involved early in projects, applying integrated project-delivery methods to help improve data sharing with architects. Still, the company often builds its own construction models.

“There are basically design-intent models and then there are construction models, and they are different in what they are intended to do,” Cunz adds. “With design-intent models we see an opportunity to collaborate, do analysis, do validation and look at schedules early. In the construction phase, traditionally we’re building from scratch because of the amount of detail required in a construction model [that isn’t in a design model].”

Cunz says that when a project is in the schematic design phase, Mortenson will work with the design team’s model to give architects feedback on costs and analysis. However, it won’t create its own model at that point because the design is still evolving.

“Once it gets to the construction documents phase, we’ll take their model and start migrating anything we can into the construction model we build,” Cunz adds.

He says that even with the added work to build the construction model, the process ultimately saves money. Mortenson has tested its theory during construction of the $200 million University of Colorado Health Sciences Center Research Complex II in Aurora, Colo., which is scheduled for completion this summer.

The company collaborated with architect KlingStubbins of Cambridge, Mass., to share all available data to create BIM models. In the end, the project saw a 37% reduction in requests for information compared to the amount generated during construction of Research Complex I, which didn’t use BIM. Research Complex II was designed by KlingStubbins and built by Hensel Phelps Construction of Greeley, Colo.

“If you look at just the administrative costs - writing an RFI, answering it, processing it, creating a solution and then responding - we had a 2-1 return on investment using BIM,” Cunz says.

Holder Construction of Atlanta is currently researching the benefits of applying BIM to the estimating process. Michael LeFevre, the firm’s vice president of planning and design support services, says that to date the company has been mostly focused on the 3D geometry and collision detection benefits of BIM.