TL;DR: Design-build is the most profitable delivery model in construction — and the one that can destroy your margins fastest if you don't have systems. The key is separating pre-construction from construction into two contracts, locking scope early, and managing your architect like a subcontractor. This breaks down exactly how to run it.
Traditional design-bid-build is a relay race — architect finishes drawings, hands them off, you build. Design-build is a triathlon — you run every leg. The architect works for you. Every decision flows through your company.
That leverage is what makes it more profitable. You optimize the design for your crews, reduce labour hours, compress the schedule. But the exposure is real: the architect's mistake is your mistake. The client sees one company — yours. Systems turn the additional responsibility into additional margin instead of risk.
The #1 mistake GCs make: signing a lump-sum contract before the design exists. You either guess high and lose the job, or guess low and eat the loss for 18 months.
The fix: Separate into two phases, even under one relationship.
Before a single line is drawn, get a pre-construction agreement signed. Cover programming, schematic design, design development, and possibly the start of CDs. You get paid for this work — fixed fee or % of estimated construction cost. Not free. This protects margin from day one and keeps the client committed.
Include language that creates a preference to move forward with you for construction — not a legal trap, but a strong expectation:
Understanding these phases prevents costly decisions at the wrong time. Each phase has a specific purpose — pricing too early or making design decisions too late will kill your margin.
The construction agreement is based on completed design — not hope. Can be lump sum, cost-plus, or GMP. You're pricing from real drawings, real specs, real sub quotes.
The architect is making decisions that directly affect your budget, schedule, and profit. Manage them the way you'd manage someone spending your money on your behalf.
Provide: target $/sqft, preferred construction methods, material lead times, permit timeline. This prevents "beautiful but unbuildable" designs.
Hold phase-gate reviews at SD, DD, 50% CDs, 90% CDs. Include your estimator, PM, and key subs. Look for:
The architect needs to know the cost impact of their decisions in real time. The client needs to know the budget impact of their requests. Build a system where both see how design choices affect the bottom line before decisions are made — not after.
Scope creep is the #1 profit killer in design-build. In design-build, the boundaries are fuzzy — a small change cascades: structural affects MEP, MEP affects schedule, schedule affects cost.
Create a written scope description: square footage, room count, finish levels, quality standards. Don't specify every detail — but specify every category. The baseline is the line in the sand that every change is measured against.
The final piece is a repeatable system so every design-build project runs the same way, not from scratch.
Shift from being a builder to a trusted advisor. Communicate proactively — weekly updates, clear milestones, transparent cost tracking. Higher trust = higher margins. Clients who trust you don't shop around and will pay for your expertise.
| Phase | Contract Type | When to Sign | Key Protection |
|---|---|---|---|
| Pre-Construction | Fixed fee or % of est. cost | Before design starts | You get paid for design-phase work |
| Construction | Lump sum, cost-plus, or GMP | After design is substantially complete | Priced from real scope, not guesses |
Bottom line: Design-build either protects your margin or destroys it. The difference is systems. Separate the contracts, lock scope early, manage the architect actively, and build a repeatable playbook. This is how elite GCs run design-build — and how Lower Coast can too.
Based on Jesse Lane, "The Design Build System That Protects Your Margin on Every Project" (2026)