The Drawings Aren’t Done. So What Exactly Is in the GMP?
I’m studying for the ARE Project Management exam right now, which means spending a lot of time in contracts—who is responsible for what, how decisions are documented, and how the process is supposed to work.
At the same time, I’m managing projects where those same concepts are playing out in real time. And one thing the study material doesn’t fully prepare you for is what happens in the space between the contract language and the day-to-day reality of a project.
A good example? Establishing a GMP while the drawings are still being developed.
On a CMAR project, the Guaranteed Maximum Price is often established before the drawings are complete. That isn’t necessarily a problem. Design and preconstruction intentionally overlap so the team can test pricing, constructability, and procurement decisions while the design is still evolving. But it creates a gap that needs to be actively managed.
An initial GMP may be based on Design Development documents, while the final GMP is negotiated as Construction Documents are nearing completion. During that time, both the drawings and the price are moving.
So when the CDs are finished, the inevitable question is: Was this already included in the GMP?
AIA Anticipates the Gap—but Doesn’t Prescribe the Workflow
Standard AIA CMAR documents recognize that a GMP may be established while the Contract Documents still require further development. A133 anticipates that the design will continue to develop after the GMP is established, as long as the development is consistent with what was shown or could reasonably be expected from the documents used to establish the GMP. [1] The CM’s GMP proposal is also supposed to identify its basis: the drawings and specifications used, assumptions and clarifications, allowances, contingency, and other pricing information. [1]
What the standard documents don’t prescribe is a detailed rolling process for reconciling an evolving design with an evolving GMP.
There isn’t necessarily an AIA-mandated checkpoint that says, “The 90% CD set was issued today; all changes must be incorporated into the GMP within X days.”
That’s where the project team needs to establish its own process.
The Architect Should Be in the Conversation
The GMP is ultimately between the Owner and Construction Manager. The architect isn’t responsible for preparing the contractor’s estimate, verifying subcontractor pricing, or approving the GMP.
But that doesn’t mean the architect should be absent from the conversation.
Under B133, the architect assists the Owner in reviewing the GMP proposal. That review isn’t intended to verify the CM’s estimate, but the architect is expected to notify the Owner and CM of inconsistencies or inaccuracies it discovers. [2] There’s an important practical reason for that.
The contractor understands the price. The architect understands what’s being designed—and the technical, coordination, code, and life-safety implications behind it.
An assumption that appears to be a straightforward cost decision may affect a rated assembly, egress strategy, accessibility requirement, envelope performance, structural coordination, or another detail the Owner wouldn’t reasonably be expected to catch.
Owners and contractors can—and will—have direct pricing conversations. But when those conversations result in assumptions, substitutions, allowances, or scope decisions that affect the design, the architect should be brought back into the conversation.
Stop Asking “Is It Included?”
One of the simplest ways to identify scope gaps is to change the question.
Instead of: “Is the site stair included?” Ask: “Show me where you carried the site stair and what you assumed.”
Instead of: “Is the exterior coating included?” Ask: “What exterior coating system did you carry?”
A line item can exist in an estimate and still represent something very different from what is being designed. The same applies to allowances.
Sitework Allowance — $150,000 tells the team very little six months later.
A useful allowance should establish: Scope + Pricing Basis + Known Exclusions.
Not Every New Detail Is New Scope
As drawings progress from DD to CD, they naturally become more detailed. If an exterior wall shown at DD gains flashings, transitions, attachments, and termination details at CD, that doesn’t automatically mean the architect added scope. Those details may simply be necessary to construct the system already priced. That’s why A133’s concept of what was “reasonably inferable” from the GMP documents matters. [1]
When something develops after pricing, ask:
- Was it shown or described when the price was established?
- Was it reasonably inferable as part of the system being priced?
- Or did the design actually change?
As those are three different situations.
In Short: Build the Process the Contract Doesn’t
If the GMP is developing alongside the drawings, the team should be able to:
1. Confirm the pricing baseline
- What drawing set is the current price based on?
- Have recent RFIs, ASIs, or other clarifications been incorporated?
- What allowances, exclusions, and assumptions are carrying scope that is not fully designed?
2. Identify what changed
- What has changed since the previous set was priced?
- Have changes across architectural, structural, civil, MEP, and landscape documents been reconciled?
- Are there conflicting drawings or scope gaps that need clarification?
3. Close the loop with pricing
- When will those changes be incorporated into the estimate?
- What is a reasonable turnaround for pricing updates?
- Has the architect reviewed the updated assumptions and exclusions against the current design intent?
4. Reconcile before the GMP is finalized
- Can the team clearly trace what is included, excluded, or still unresolved?
- Are outstanding scope or pricing questions assigned to someone for resolution?
- Is the estimate organized consistently enough to track scope from one pricing iteration to the next—and eventually into the Schedule of Values?
One practical tip: Keep each iteration of the iGMP/GMP in the same general format, and carry that structure into the Schedule of Values where possible. When line items move, disappear, or get reorganized between estimates, it becomes much harder to tell whether scope changed, was missed, or was simply carried somewhere else.
How often? At minimum, run this reconciliation at each formal pricing update and before the GMP is finalized. During DD and CDs, it may also make sense to check in every two to four weeks—or whenever a significant drawing package, RFI, or design decision could affect cost. The goal is to avoid letting months of design development accumulate before anyone compares the current documents back to what was actually priced.
Before the GMP is finalized, put the drawings and the GMP assumptions back next to each other.
In other words, close the loop.
In Summary
The contracts establish responsibilities. The project team still has to establish a communication process. The goal isn’t to eliminate uncertainty from an early GMP. It’s to make sure the drawings and the price don’t quietly evolve on parallel tracks.
Because ultimately, the most valuable question during GMP review may not be: “Is this included?”
It may be: “What did we assume was included—and does that still match what we’re designing?”
Sources / Contract References
- AIA Document A133–2019, Standard Form of Agreement Between Owner and Construction Manager as Constructor where the basis of payment is the Cost of the Work Plus a Fee with a Guaranteed Maximum Price — sample / guidance used for GMP basis, further development, assumptions, allowances, and reconciliation concepts.
https://help.aiacontracts.org/public/wp-content/uploads/2020/12/AIA-A133-2019-sample.pdf - AIA Document B133–2019, Standard Form of Agreement Between Owner and Architect, Construction Manager as Constructor Edition — comparative / guidance used for the architect’s GMP review role and incorporation of agreed assumptions and clarifications.
https://assets.aiacontracts.com/ctrzdweb02/zdpdfs/aia-b133-2019-comparative.pdf - AIA Contract Documents, B133–2019 FAQ — supplemental guidance on the architect’s services in the CMc/CMAR delivery model.
https://help.aiacontracts.com/hc/en-us/articles/1500009312241-faqs-owner-architect-agreement-b133-2019-cmc
Editorial note: References are to standard AIA forms/guidance. Actual project agreements may modify these provisions. Confirm the executed agreements before applying contractual conclusions to a specific project.
