Quick answer: Design-build puts one contract, and one point of accountability, over both design and construction. CM/GC (also called Construction Manager at Risk) keeps the owner’s contracts with the designer and the contractor separate, but brings the contractor in early to advise on cost and constructability before design is finished. Both are legally recognized alternative delivery methods in Colorado, with CDOT’s authority to use design-build established under C.R.S. § 43-1-1401 and applied through CDOT’s own Alternative Delivery Program for transportation projects. Neither is universally better.
The right choice depends on how much design certainty the owner has before construction needs to start.
Why This Choice Matters Before Design Even Begins
The traditional approach, design-bid-build, is still the most common public delivery method: hire a designer, finish the plans, then competitively bid the finished design to contractors. It’s straightforward and price-competitive, but it separates design and construction into two sequential phases with no contractor input until the design is already locked.
Design-build and CM/GC both exist to solve that specific problem: getting contractor expertise into the room while the design can still be changed, not after.
How Design-Build Works
Under design-build, the owner contracts with a single design-build entity that’s responsible for both designing and constructing the project. That team is contractually accountable for the whole outcome, which tends to reduce the finger-pointing that can happen between a separate architect and contractor when something goes wrong.
What this means in practice:
- Owners typically select a design-build team based on qualifications and a conceptual proposal, not a finished design
- The design-build entity carries single-point responsibility for both design accuracy and construction quality
- Schedules often compress, since construction can start on portions of the project before the full design is complete
In Colorado, CDOT’s authority to enter design-build contracts is established under C.R.S. § 43-1-1401, and CDOT has used design-build procurement on major Front Range corridor projects for years.
How CM/GC Works
CM/GC, also referred to as Construction Manager at Risk (CMAR), keeps the owner’s design contract and construction contract separate, but brings the construction manager on board during design, not after it.
What this means in practice:
- The owner holds one contract with the architect/engineer and a separate contract with the CM/GC firm
- The CM/GC provides cost estimating, scheduling input, constructability review, and value engineering while the design is still being developed
- Once design reaches an agreed point, the CM/GC negotiates a Guaranteed Maximum Price (GMP) for the work, rather than winning the job through open bidding on a finished design
CDOT’s Alternative Delivery Program uses CM/GC alongside design-build for transportation projects, selected through CDOT’s own prequalification and procurement process.
Side-by-Side Comparison
| Design-Build | CM/GC | |
|---|---|---|
| Contracts | One contract covers design and construction | Separate contracts for designer and contractor |
| Contractor selected | Early, often based on qualifications and concept | Early, based on qualifications and fee |
| Price certainty | Often established earlier in the process | Established later, via negotiated GMP |
| Accountability | Single point of responsibility | Shared between designer and CM/GC |
| Best fit | Projects where speed and single accountability matter most | Projects where the owner wants more control over design decisions |
Where CDOT Fits In
CDOT’s Alternative Delivery Program applies both methods to Colorado highway and infrastructure work, with contractor selection tied directly to CDOT prequalification in the relevant work category. A firm bidding design-build or CM/GC work still has to demonstrate the financial capacity and category-specific experience CDOT requires of any prime contractor on state-funded work.
That’s part of why delivery method and contractor qualification aren’t separate conversations on a public project. The delivery method determines when a contractor gets involved; prequalification determines whether that contractor is eligible to be involved at all. As a CDOT-certified civil contractor, 633 Construction works within both delivery structures regularly, which shapes how early we’re brought into a project’s planning conversation.
Which Method Fits a Specific Project
A few questions tend to point toward one method or the other:
- How firm is the budget, and how early does it need to be locked? Design-build often produces earlier price certainty. CM/GC allows more design flexibility before the price is set.
- How much does the owner want to control design decisions directly? CM/GC preserves a separate designer relationship the owner can direct more closely. Design-build consolidates that control into the design-build entity.
- How complex or technically challenging is the project? Both methods benefit complex work, but CM/GC’s negotiated GMP process can be useful when scope or site conditions carry real uncertainty going in.
- How compressed is the schedule? Design-build’s ability to start construction on early packages before full design completion often produces faster overall delivery.
None of these questions has a universally right answer. They’re the actual conversation worth having with a civil contractor early, before a delivery method gets locked in by default.
Key Takeaways
- Design-build uses a single contract and single point of accountability for both design and construction.
- CM/GC keeps separate designer and contractor contracts, but brings the contractor in during design to advise on cost and constructability.
- Both are authorized for Colorado public projects, with CDOT’s design-build authority established under C.R.S. § 43-1-1401 and both methods used through CDOT’s Alternative Delivery Program.
- CM/GC produces a negotiated Guaranteed Maximum Price rather than a competitively bid fixed price.
- The right method depends on budget certainty needs, how much design control the owner wants to retain, and schedule pressure.
FAQ
What’s the main difference between design-build and CM/GC?
Design-build combines design and construction under one contract with one accountable party. CM/GC keeps separate contracts for the designer and the contractor, but involves the contractor early in the design process.
Is CM/GC the same as Construction Manager at Risk (CMAR)?
Yes. CM/GC and CMAR refer to the same delivery method, just different terminology used depending on the region or agency.
Are these delivery methods legal for public projects in Colorado?
Yes. CDOT’s authority to use design-build for transportation projects is established under C.R.S. § 43-1-1401, and CDOT’s Alternative Delivery Program uses both design-build and CM/GC.
Does a contractor need to be CDOT prequalified to work on a design-build or CM/GC project?
For CDOT-funded work, yes. Prime contractors on state highway and infrastructure projects need to be prequalified in the relevant work category regardless of which delivery method is used.
Which delivery method is faster?
Design-build often produces a faster overall schedule, since construction can begin on early packages before the full design is complete. CM/GC can also compress schedules, but its negotiated GMP process typically takes longer to finalize pricing than design-build’s earlier price certainty.
Talk Through the Right Delivery Method for Your Project
Choosing between design-build and CM/GC is easier with a civil contractor at the table early, not after the delivery method is already locked in. Talk with our team about your project, or learn more about our design-build and CM/GC services.
