In the Trenches with BIM

In this third installment of a three-part series on building information modeling, Scott Sedam talks with design professionals who are leading the transition from CAD to BIM.

By Scott Sedam, Contributing Editor | December 27, 2011
BIM for builders, BIM, building information modeling, BIM for home builders, sco

We covered a lot of ground in our first two articles on building information modeling (BIM) and how it serves as a great enabler for Lean — the relentless pursuit, identification, and removal of waste in product and process. First, in “BIM – Pipe Dream or Promised Land” (Professional Builder October 2011, page 40), we built a vision of the kind of design BIM can perform on a broad basis that is rarely done today, because without BIM tools it requires talent beyond merely rare. For example, the ability to not just visualize but actively analyze a structure in 3D to avoid conflicts and “collisions” that cause immediate costs or set up time bombs for future problems. That’s just for starters.
In the second article (“Defining BIM – Vision Meets Reality,” PB November 2011, page 38), we took a hard look at the wide-ranging definitions of BIM and the sobering time and technological demands that integrating 4D (cost) and 5D (time) capabilities into BIM place upon builders, architects, and engineers.

Once again, it starts to sound complex, but after reading both articles, Sean Degen, former National VP of Product Development for Pulte Homes, emailed this brief definition of BIM: “BIM moves complexity upstream to simplify construction and thoroughly understand material application and cost.” That says it about as simply as you can and provides a good launch point for this third article in the series on BIM.
I heard from a lot of those in the trenches; those who deal with BIM creation and implementation or observe BIM efforts from close up.

Their insights are invaluable as we struggle to get our arms around this wondrous, sometimes overwhelming, and frequently intimidating technology. Much of what these practitioners offer focuses on how we get from here to there. To transition from CAD to BIM, some of the biggest obstacles reside in the conventions and traditions of the field of architecture itself. Brad Blissit, president of Integrated Structural Concepts in Phoenix, knows of what he speaks. Brad’s firm not only designs using BIM, but also builds foundations and erects frame packages. Blissit observes:

“Architects don’t draw for construction purposes. Most architects still use the 4- and 6-inch wall width convention. Why 4 inches? Let’s do the math: a 2x4 is actually 1-1/2 inch thick by 3-1/2 inches wide, plus drywall on each side. Typical residential drywall is 1/2 inch wide, so 3-1/2 inches plus 1 inch equals 4-1/2 inches if you’re going to include the drywall. But they draw it as 4 inches. These dimensions are used at least 10 different times throughout the design and construction process. So when the living room wall is shown 12 feet from the outside wall, it’s not really 12 feet, is it? So the structural engineer, the truss manufacturer, the framer, the plumber, and the concrete form-setter all have to reinterpret where the wall is supposed to go.”

The results are errors, rework, wasted time, and field “work-arounds,” and once you understand the costs of doing it this way, it is completely unacceptable. Why do cabinet companies make a costly measuring trip to nearly every house before installation? Now you know. Even if the framer builds it exactly to plan, the result, in this case, could be 5 inches off either way. Blissit goes on to say:

“Ninety-five percent of all the plans we see have the wrong elevation dimensions. Architects don’t understand or don’t want to be bothered with the fact that a 9-foot stud (the most commonly used today in our markets) is 1045/8 inches in a trimmed height dimension. So again, when we roll out a set of plans on a building, we have to do all the mental gymnastics to figure out what the architect intended. Do we really have to cut each stud to his off-standard dimensions? Can we use precut studs? What’s the impact on doors, windows, and drywall? This is just one of those ‘it’s the way we’ve always done it’ things. We think it comes from the old days of hand drafting, when it was hard to see that 1/2-inch mark on the old scales. Or maybe the fractions didn’t look as clean on the drawings.”

Whatever the source, you can see what BIM is up against. How do we get architects, along with builders, suppliers, and engineers, to change 100 years of tradition? In architects’ defense, I can recount many of them describing how they want to produce the level of detailed working drawings that just a 2D CAD drawing needs to work effectively in the field, but so often builders will not cough up the additional money even when they end up paying a large multiple of that in field mistakes and rework. Will they pay for going to the next level of BIM? Certainly not until builders become convinced that the leap to BIM will save more than it costs. Whose job is that? We could start a long debate over that question, but regardless, no single group on their own can make the changes needed for successful BIM implementation.

Despite the obstacles, BIM does not lose its promise to solve and prevent many of the problems that vex home builders, suppliers, and trades from design to purchasing to schedule. Mike Kozlowski, president of engineering firm Apex Technology of Jacksonville, Fla., made this observation:

“BIM is different than conventional building in one very important aspect: most of the problems encountered in the field will present themselves in the design and modeling phases, prior to any construction. This is what happens when you take notes in text format and transform the design documents into a dimensionally correct model. There is good news and great news in this concept. The good news is that you can better navigate blatant framing issues, such as mechanical runs through the floor system, and solve them prior to material delivery. Two wasted trips, a VPO for the floor truss repair, and a back charge are all avoided. The great news is that you can also utilize the model during your senior leadership plan review sessions. Deciding on the look or feel of an architectural feature, such as an interior vault, is easy now that you are able to inspect and view the feature from multiple vantage points. The individual skill required to visualize this just became obsolete.”

Kozlowski further describes the even greater promise in the area of integrated project delivery (IPD). IPD is often described as if it is a part of BIM, yet most practitioners look at it the other way around — BIM is a set of tools that are an essential part of IPD. As Kozlowski puts it:

“Let’s get back to collaboration and decisions. Here is the real opportunity for the builder. In a fragmented industry where most decisions and conflicts are hashed out on site, there is much room for improvement through collaboration with the major stakeholders of the project. Collaborating to simply coordinate the design documents is a good goal, but with a little extra effort you can implement Lean principles and identify best methods. For example, invite your framer, component designer, and structural engineer into a conversation and learn how you can increase energy performance while reducing framing lumber by moving your first-floor headers into the floor system. That will get your attention. Decisions and conflicts consume valuable time and money during construction. The whole concept of Lean is to eradicate all forms of waste in a project. Understanding this waste is square one, deciding against waste is the next step, and implementation is the coup de grace.”

Kozlowski’s point addresses one of the most obvious yet largely ignored realities of the building process — all of these decisions, every single one regarding design, plans, specifications, components,  products, vendors, options, schedule, and warranty, and the roles of all constituents, get made eventually, even though a large share are out of sight and thus out of mind. Taken as a whole, BIM does not add steps to the process of designing and building homes, it ferrets out all of the steps, puts them in order, and gets everything done earlier in the process, wherever possible. The net effect then is to reduce the total number of steps. Getting there, though, will take a lot of hard work.

Someone who has been living and breathing BIM every day for years is Richard Boothman, an AEC (architecture, engineering, and construction) Consultant for Ameri-CAD Inc., purveyors of VisionREZ, one of the leading BIM systems. Boothman began his career as a residential architect but has spent the past 15 years in the CAD world and the last seven on BIM. Boothman comments further on the idea of collaboration and avoiding the crutch of field verification:

“Collaboration is a word thrown around a lot. It used to mean a few people in a room with red pens going over a set of plans right before the first foundation pour. With BIM we can start the process just a few days into the design; sharing information back and forth brings out better homes, better designs, and ultimately happier homeowners. I talk to a lot of builders who think their plans are good enough, that the guys in the field can fix them. Some even put notes on the plans like ‘verify in field,’ knowing full well that it is wrong on the plan set. With BIM there are no more ‘verify in field’ issues. Find the problems in the office, correct, fix the plan set, get through permitting faster, get to first pour faster, and eliminate the change orders that happen with new product. Use that model to drive the takeoff directly and decrease site waste, supplier drops, water-logged material — the issues that can be solved abound.”

When you hear about all the benefits and participate in a well-run demo, excitement over the potential with BIM is hard to resist. Yet the obstacles are considerable. Boothman offers these cautions:

“In the same breath of ‘things that can be fixed’ are the ‘things that can be broken.’ Don’t assume BIM will only solve issues and not create any new ones or reveal problems. You will uncover holes in your process that are not easy to confront. BIM can break things that were not broken before. It is not a short-term commitment to move to BIM; it is an investment in time, resources, hardware, and money. You will not see a 40 percent improvement the first month, but in the coming months that improvement will grow and surpass initial expectations. Some builders we work with turn around full takeoffs within an hour, where it used to take days. That change took a full year. Ultimately, there is a strong payoff, but the process to get there can be painful.”

As difficult as technological roadblocks can be, in the end they are merely big task lists — things to be done that may take time and money, but are still doable. Organizational issues, however, are much more difficult to get a handle on, and these hurdles can derail BIM, Lean, or any other organizational change initiative. Sean Degen cites four common organizational issues based on his experience:

  1. Perception — Most builders view architectural services and product development as support services similar to IT and HR, rather than an integral part of the home-building process with the ability to utilize technology to improve the overall business.
  2. Resistance — The difficulty in crossing over organizational silos with new ideas is always a challenge, especially in good times because everyone is too busy.
  3. Business inertia — The immediate cost to change has always been a deciding factor in so many decisions, even when the long-term gains far outweigh the short-term financial constraints.
  4. Lack of will — A change like BIM affects multiple disciplines, and the prospects of taking anyone’s focus off of the status quo is just too much for many senior executives to consider.

To Degen’s comments I add two. First, in these difficult times, the primary obstacle cited for almost any change is “we have too much on our plates.” Everyone is short-staffed, working multiple jobs and too many hours. The irony of Lean, BIM, and IPD, though, is that implementing them would do wonders to clear the excessive workload off of everyone’s plate. Second, senior management fears, with some justification, that when all the money is spent they won’t find a meaningful reduction in either house cost or indirects, both of which should be visible. Having said that, we find that when senior management fully understands the undertaking, trusts their people to follow through, gives them the training and skills they need, and imparts discipline in a change process, the results are always forthcoming.

Todd Hallett is an independent architect and former CEO of a 225-unit-a-year production builder. Smaller firms such as Hallett’s do the majority of the architectural design for residential home builders in the U.S. today. I asked him to describe how he sees the application of BIM software and tools evolving in home building over the next decade. Hallett offers:

“One of the greatest benefits of BIM is its ability to expose design problems that create conflict among trades. With BIM-established zoning for mechanicals and framing, for example, you eliminate unexpected framing drops and chases, as well as poorly planned mechanical runs. Small adjustments can make a big cost and efficiency difference, such as better placement of the air handler relative to the condenser to reduce the length of the condensate. All of this gets worked out before the first home is built. The proper application of BIM creates powerful tools that were previously beyond the grasp of architects, but implementation remains a challenge. Extensive training is required to become fluent in the 3D language of BIM systems. Advancement in this system can be laborious for architects, and the question for many will be if the juice is worth the squeeze.”

In this series on BIM we have tried to provide a balanced picture and an enticing vision of the promise and potential of BIM with a no-tears look at the considerable obstacles. We have endeavored to simplify the concepts while being realistic about the complexity found in implementation. That’s a tall order, and we will no doubt return to the subject in future articles as we learn more and implementations proceed. There is no question, however, that BIM looms as a significant arsenal in the war against waste and will change the face of residential construction in the years to come.

Scott Sedam is president and founder of TrueNorth Development. He and his seven TrueNorth colleagues focus on the adoption of Lean Operating principles into the home-building industry, serving more than 200 builder and supplier clients in the U.S., Canada, and Australia. Sedam welcomes your feedback at


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