GMAX, Cost-Plus or Competitive Bid: Choosing a Contract Before You Choose a Builder

Most owners pick a contractor first and a delivery method second. It usually works out backward. The delivery method sets who carries cost risk, how much visibility you get into subcontractor pricing, and how much room there is to change your mind once steel is in the ground. Geddes-Armstrong Construction offers five: Construction Management, Cost-Plus Contracts, Competitive Bids, Design-Build, and Hybrid Delivery Models. Each one solves a different problem. None of them is universally correct.

Construction Management: hands-on, coordinated

Under Construction Management, the contractor manages the build day to day while the owner keeps visibility into decisions as they happen. It suits projects where the scope is reasonably well defined but the owner wants a seat at the table for sequencing calls, substitution decisions, and trade coordination rather than finding out about them after the fact. It is not the fastest route to a fixed number up front, because a coordinated build process leaves some pricing decisions live longer than a lump-sum bid would.

Cost-Plus: transparency, and the discipline it requires

Cost-Plus Contracts give an owner line-by-line visibility into what a project actually costs, plus a contractor fee on top, instead of a single blended number that hides the underlying breakdown. The trade-off is direct: cost-plus asks the owner to participate in decisions as they arise, because the collaborative structure that makes it transparent is the same structure that keeps it open-ended without active involvement. It rewards an owner or a building committee that wants to see the math, and it demands time from that owner or committee to look at the math when it matters.

Competitive Bid: value through market pricing

A Competitive Bid puts a defined scope in front of the market and lets pricing determine the winner. It works when design is complete enough that everyone is bidding the same thing, and it is the most straightforward path to comparing dollar figures across contractors. It works less well when scope is still moving, because a lump-sum number priced against one set of drawings is not the same commitment against a revised set, and the change-order process is where a competitive bid can quietly become a much less competitive one.

Design-Build: single-source accountability

Design-Build contracts both the design and the construction through one company, which removes the handoff between an independent architect and a separate contractor. That reduces change orders that originate from design-to-construction miscommunication, and it allows early construction activity to begin before every design detail is finalized, because the same team is responsible for both halves and has no incentive to protect one discipline at the other's expense. The trade-off is that the owner gives up the traditional check of an independent architect representing their interests against the builder.

Hybrid: customized to what the project actually needs

A Hybrid Delivery Model blends elements of the four above, customized to a project's scheduling, budget, or design goals rather than forcing the project into one standard template. It is the right answer more often than owners expect, because few real projects sit cleanly inside one of the four categories once site conditions, funding timelines, and design maturity are all accounted for.

What a GMAX actually does for you

A Guaranteed Maximum Price sits underneath several of these models, most often Construction Management, and it does one specific job: it caps the number an owner can be billed, while typically sharing savings if the actual cost comes in under that cap. Noble Public Schools recorded exactly why this matters to a public building committee, in their own words: "This is the first project I was not forced to make cutback on due to cost overruns. GAC gave us an original guaranteed maximum price (GMAX) that they remarkably were able to stay within." That is the entire case for a GMAX in one sentence. A guaranteed number that gets held is worth more to a school board or a church building committee than a lower number that does not.

• Scope not fully defined yet, owner wants influence over decisions as the project develops: Construction Management
• Owner wants full cost transparency and is prepared to stay engaged in ongoing decisions: Cost-Plus
• Scope and design are complete, and price comparison across bidders is the priority: Competitive Bid
• Owner wants one accountable team and the option to start construction before design is finished: Design-Build
• None of the above fits the funding timeline or design maturity cleanly: Hybrid

Ask a bidder which of these models they are proposing, and ask them to say plainly what it means for your cost risk and your visibility. If they cannot answer both parts without hedging, that tells you something before the contract is even signed.