Design-Build vs. Design-Bid-Build: Where the Change Orders Hide

Design-bid-build doesn't fail at construction — it fails at the contract seam between the architect and the builder. Here's the exact mechanism that turns a 'low bid' into the highest number on the table, and what True Design-Build changes about it.

The two methods, and where the seam sits

Most owners think the choice between design-build and design-bid-build is a matter of preference — two roads to the same building, one a little faster. It isn't. The two methods put the contractual seam between design and construction in completely different places, and that seam is exactly where change orders are born. Design-bid-build (DBB) is the traditional sequence: you hire an architect, they design the project to completion, you put finished drawings out to two or three general contractors, they bid, you pick one. Design and construction are two separate contracts with two companies that meet for the first time at the bid table — and the architect and the GC have no contract with each other. Design-build (DB) collapses that into one contract: a single entity is responsible for both design and construction, from first sketch to certificate of occupancy. The distinction that matters isn't 'one company versus two.' It's where the seam sits — and therefore who absorbs the cost when a drawing is incomplete or wrong. In DBB the seam runs through the middle of your project; in DB there is no seam to fall into. This isn't a pitch for one method — there are real projects where DBB is the right call — but the change-order mechanism is so consistent, and so poorly understood by first-time owners, that it deserves to be spelled out plainly.

Where the change orders actually hide

Owners assume change orders come from changing their minds — nicer tile, an added wall. Those exist, and they're the owner's own doing. The expensive, demoralizing ones come from gaps in the design documents the bid was never measured against. In the field these are called holes and busts — and they are two distinct failure modes:

• Holes: things missing from the drawings entirely. A floor drain that has to exist but was never drawn. A conduit left off the electrical sheet. A shielded wall the radiation report required but the architect didn't reflect. It has to be built, it wasn't in the bid, so it becomes a change order.
• Busts: things drawn, but drawn wrong. An operatory dimensioned too narrow for the chair and delivery unit. A plumbing rough-in that conflicts with the slab the previous tenant poured. A rooftop unit specified at 3-ton when the air-change requirement needs 5-ton. Each bust forces a redesign, then a rebuild, then a change order.

Here is the mechanism in a design-bid-build project. The architect designs in a vacuum, because no builder is in the room pricing the work in real time. The completed drawings inevitably contain some holes and busts — not because the architect is bad, but because no construction document set is ever perfect, and no architect prices subcontractor labor in Frisco in real time. The GCs bid those imperfect drawings. The honest GC bids what's drawn and warns you the documents look thin. The aggressive GC bids what's drawn, says nothing, wins on price, and recovers margin later through the change orders the holes and busts guarantee.

Why the seam turns adversarial

Why holes and busts become your bill rather than someone else's is structural, not personal. In design-bid-build, the architect and the contractor each have a separate contract with you and none with each other. When a hole surfaces in the field, two economically rational positions collide: the architect's fee is already largely earned, so their incentive is to defend the drawings — 'the contractor should have caught that in the bid.' The contractor's margin on a lean bid depends on recovering it, so their incentive is to price every missing item as extra work — 'that's not in our scope, here's a change order.' Under their respective contracts both parties are technically right. You pay the change order, or you pay a lawyer, and often both. That battle — 'I drew it right' versus 'it can't be built that way' — is baked into the contract structure, not the personalities. [Pereff operating principles]

The cost was decided before the bid went out

There's a well-documented principle in project delivery: the decisions made in the first 15–20% of a project's timeline — programming, schematic design, design development — lock in the large majority of final project cost. Read that against the design-bid-build sequence and the problem is obvious: the builder shows up after the 60–80% has already been committed. A good GC reading the finished drawings can still find value-engineering opportunities, but the high-cost decisions are now load-bearing — changing them means revising drawings, paying additional design fees, and burning weeks the owner rarely has. The single most powerful cost lever in construction — early preconstruction and value engineering — has been spent before the person who knows construction costs is even in the room.

What True Design-Build changes — and what it doesn't

Pereff calls its method True Design-Build to distinguish it from the watered-down version some firms market — a GC subcontracts an architect but still designs in a silo and prices at the end. True Design-Build means the team that designs the project is the team that builds it, pricing continuously as the design develops. It doesn't make holes and busts impossible; it changes when they're caught and who pays:

• Budget validation at schematic design, not at bid. The builder runs cost models alongside the architect from week one. If the schematic is 20% over budget, you know in week four — not after sixteen weeks of design and three bid rounds.
• Holes and busts caught in design development, not in the field. MEP coordination — the plumbing-versus-slab conflict, the undersized rooftop unit — happens while the architect is still drawing, when a fix costs an eraser, not a demo crew.
• No contractual seam to fall into. The designer and builder are the same accountable entity, so there's no gap between 'what was drawn' and 'what was bid' to argue over. The drawings that go to permit are the drawings the builder intended to build.
• A Guaranteed Maximum Price established earlier and held with more confidence — the natural output of a budget the team has carried the whole time, not a bid against unfamiliar drawings.

When design-bid-build is still the right call

Design-bid-build isn't a trap in every case. It can be the right method when you need maximum price competition on a fully and rigorously completed document set, when a public or institutional procurement rule mandates competitive bidding, or when the design is simple and well-precedented enough that the holes-and-busts risk is low. The risk concentrates where complexity and specialty MEP live — medical, dental, restaurant, and ground-up work — because those are the project types where incomplete or mis-coordinated drawings are most likely and most expensive. So the first question isn't 'which GC will bid lowest?' It's 'where does the seam between design and construction sit, and who pays when the drawings are wrong?' If the answer is 'you do,' a low bid is just a down payment on a higher final number.