In case you haven’t noticed, the building design and construction industry has been leaning more and more towards the Design-Build (D-B) method of project delivery. There has been a lot of politicking about how D-B is faster, cheaper, and in general, better than traditional Design-Bid-Build (D-B-B) projects. On the surface, those claims can be pretty easy to substantiate by picking and choosing a few moderately successful projects to showcase. However, once you dig a little deeper, you may begin to see that D-B is NOT for everyone. Now don’t get me wrong. D-B is perfectly fine as a method of project delivery, under the right circumstances!
Take the example of a public works project like replacing a waterline, or even replacing a small highway bridge. This type of project is great for design build because the owner (the public agency) and the contractor both know exactly what their job is. Let’s not get bogged down into the possibility (or probability depending on your level of cynicism) that one of the two parties doesn’t know what they are doing or lacks the proper experience. Just go with me on this one.
So when that waterline project begins, a bid is put together, negotiated, etcetera. The contract is signed, and design documents get produced. If you were to compare those documents to a standard set of docs on a D-B-B project, they would probably be sub-par, but that’s OK with D-B! The owner doesn’t need to see seventeen different thrust block details for different configurations or whatever. If they see a note that says “provide thrust blocks” that is perfectly acceptable because they actually understand what it entails. More importantly, they understand that the contractor understands what it entails. Let’s be clear here. We’re talking about change orders.
There are literally books on the subject of finding and getting paid for change orders. Just Google it if you don’t believe me. In a traditional D-B-B project, a missing detail is a sure-fire way to get a change order on your project. “What thrust blocks? You didn’t have a thrust block detail. That’s gonna cost you.” Now I’m not about to get into the debate over the validity of this kind of thing, but I don’t think anyone is going to argue the fact that it does happen. When operating under a D-B project, these kind of things can go away since the contractor is the one responsible for the design documents, which are a description of what they actually plan to build. D-B docs don’t need to be as detailed because the contractor already knows how they are going to build it so why waste the design portion of the fee drafting it all into excruciating detail? More importantly, the contractor knows they have to provide those thrust blocks so they are (probably) not going to try and go after additional money by “forgetting” to put them in the design drawings. Yes, I know there are exceptions to every rule. I’m talking generalities here.
Now we get to the point where the D-B system starts to break down. Or at least, where it CAN break down. The true key to the success of D-B is control. More specifically, a lack of control. The more complex a project is, the less control the owner has over the finished product. Let’s go back to that bridge example. If the owner’s requirement was “build a bridge” then they have no control over what that bridge will look like. Will it be concrete? Steel I-beams? Trusses? The simple answer is the Owner’s Program of Requirements (OPR). This document contains all of the requirements specific to this project in the form of written description. So let’s take the example a little farther. Say the OPR indicated steel trusses for the bridge. What shape of steel trusses? Any preference for the individual members? Are L-angles and exposed bolts/rivets acceptable? Or does it need to be something fancier like tube steel or have concealed connectors? The OPR could go into that level of detail if necessary (and if the owner really did care about such things), but let’s jump ahead to a much more complex project.
Take the example of a D-B project to construct a new high school. How in the world can an OPR document handle the myriad requirements for such a project? One possible answer is the bridging document. This is a set of documents prepared separately by an A/E firm and brought to an intermediate percentage of completion. The D-B contractor then bids on those documents with the understanding that they will then complete the design and construct the project. Sound a little bit more like D-B-B? Well, it is… to a point. Imagine for a moment that we were in a traditional Design-Bid-Build project where the contractor bids the project off of a 40% complete set of drawings. Remember what I said earlier about missing details leading to change orders? With more than half of the documentation missing you can bet your bottom dollar that the change orders will start rolling in. Getting back to D-B and bridging, things are similar but not quite as bad. The D-B contractor is responsible to complete the design documents, so a lot of missing details will be filled in. However, there can still be some gaping holes in the project scope where the bridging documents are understandably incomplete.
Say that the high school bridging documents showed all of the classroom layouts, all of the exterior wall heights, and even went so far as to provide rough duct locations. Now the D-B design team lays out the actual mechanical equipment to be installed and finds out that the plenum space is not nearly deep enough to accommodate the structure, ductwork, and light fixtures. The decision comes down: Raise the roof! This of course entails raising all of the exterior walls as well, additional bracing for the interior partitions, and who knows how many other small changes. You may have noticed by now the 800 lb. gorilla sitting in the room. Yes, that’s the change order. The D-B had no way of knowing that such a change would be necessary when they were assembling their bid. The design team on the bridging documents didn’t get into enough detail on their end to justify it as an omission. So now the owner gets stuck with an unpleasant decision. Shell out the extra cash, or make some drastic cuts in other areas of the project to compensate. Yes, I know there are other solutions to this particular problem like narrow ducts, lower ceilings, etc. but stay with me people! This is all just hypothetical anyway, don’t get hung up on the details.
Speaking of details, that is exactly what will be missing from the documents, missing from the bid, and end up causing just this sort of problem. Now let me bring you back to my original premise. Design build is just fine under the right circumstances. This kind of lack of control is absolutely key to D-B. Of COURSE the design team didn’t know about the problem. Of COURSE the D-B missed it in their bid. So of COURSE the owner should pay to fix the problem! Changes like this for complex D-B projects are absolutely inevitable. The owner has to go into this with their eyes open and their contingency fund full. In our hypothetical case, the school board should have had several extra percentage points tucked away just for such an occurrence. If they did, and if they understand that these things happen, then the project can turn out to be a tremendous success! If they didn’t, and they treat the project as if it was a D-B-B, things will fall apart real quick.
In D-B-B both the Architect and the drawings are on the owner’s side specifically to chain the contractor to a hard price. The majority of change orders will come from unexpected conditions, unintentional omissions in the drawings, or requests by the owner themselves. In D-B with bridging, the omissions are built in to the process! Trying to say that the contractor should have somehow figured out this problem during the bid and that they must now eat the price of raising the roof structure is a sure way to get into a legal battle that nobody wants. Furthermore, the Architect is no longer on your side to defend your position. Maybe if this was a D-B-B there was a general note about coordinating trades in plenum space. That might not be enough to win the argument, but it is at least a point of contention that can be used to negotiate for a lesser change order. With D-B that kind of safety net doesn’t exist. The only thing to fall back on is an OPR and an incomplete set of bridging docs.
To summarize, Design Build is not “good” or “bad” in and of itself. It is simply one method for delivering a completed project. As long as everyone goes into it with both eyes open, everyone should come out of it ahead. Where real caution is needed is with the politicking I mentioned earlier. If an inexperienced owner gets it in their head that D-B is always the way to go and doesn’t fully understand the implications then trouble will be brewing in short order. I suppose that the real lesson to be learned here is that you don’t have to keep your eyes shut to keep an open mind.