Fixed Price in Architecture: How It Actually Works

The most common thing we hear in a first consultation is some version of: "The last architect we worked with said it would cost X. It ended up costing 2X."

This isn't a story about bad architects. It's a story about a contract structure that puts all the risk on the client while offering them no protection. Open-ended contracts — where costs are estimated but not guaranteed — are the default in most of the construction industry in Mexico and elsewhere.

We don't use them.

What a fixed-price contract actually means

A fixed-price contract means exactly what it says: the price is fixed. Before construction begins, you know:

• The total cost of labor and materials
• The payment schedule (broken into milestones)
• What's included and what's excluded
• The process for handling any changes you request

If material costs increase while we're building, that's our problem, not yours. If a subcontractor comes in over budget, we absorb the difference. The number we agree to at the start is the number you pay at the end — unless you explicitly request changes to scope.

How we get to a fixed price

A reliable fixed price requires detailed design work before the contract is signed. This is where most firms take shortcuts — and where problems begin.

Our process:

1. Free consultation (60 min) We visit your site, understand your program, and discuss your budget range. At this stage, nothing is committed and nothing costs money.

2. Concept design Based on the consultation, we develop a concept — spatial organization, material palette, rough volumes. This phase establishes whether our approach and your vision are aligned before significant investment.

3. Schematic design + preliminary budget With an approved concept, we develop floor plans, sections, and elevations in enough detail to generate a meaningful cost estimate. The preliminary budget has a margin of ±10%.

4. Executive project Full construction drawings: structural, architectural, MEP (mechanical, electrical, plumbing), details. This is the document set that allows us to price the project accurately and that contractors bid against.

5. Fixed-price contract With the executive project complete, we issue a fixed-price contract with milestone-based payments. The margin at this stage is essentially zero — the price is the price.

Why most firms don't offer fixed prices

The honest answer: it requires more upfront work.

To offer a fixed price, you need a complete set of construction documents before you sign the construction contract. That takes more time — typically 8–14 weeks for a residential project, depending on complexity.

Many clients are impatient to start building. Many firms accommodate this by starting construction with incomplete drawings and adjusting costs as they go. This feels like efficiency. It usually produces the opposite.

Incomplete drawings generate conflicts, delays, and cost overruns. The "shortcut" to starting fast reliably produces the slow, expensive outcome.

We require complete design documentation before construction begins. The extra weeks at the design stage save months of problems in the field.

Milestone payments: how the schedule works

Our contracts are structured around construction milestones rather than calendar dates. This protects both parties.

A typical residential project payment schedule:

| Milestone | % of Contract | |---|---| | Contract signing + mobilization | 20% | | Foundation and structure complete | 25% | | Roof and envelope closed | 20% | | Interior rough-ins complete (MEP) | 15% | | Finishes complete | 15% | | Punch list and final delivery | 5% |

You only pay when work is verifiably complete. We don't receive the next payment until the previous milestone is certified.

What's excluded from a fixed price

Transparency requires stating clearly what isn't covered.

Client-requested changes. If you decide mid-construction to add a room, change materials, or modify the layout, those changes are priced separately and added to the contract. This is expected — projects evolve — but changes after construction begins cost more than changes in the design phase.

Permit fees and utility connections. These are government and utility charges outside our control. We provide accurate estimates but can't guarantee third-party pricing.

Exceptional site conditions. If excavation reveals unexpected rock, contaminated soil, or archaeological material requiring special handling, this is disclosed immediately and addressed with a change order. This is rare but not impossible to predict entirely.

Everything else — labor, materials, supervision, profit — is covered by the contract price.

The question to ask every architect

Before signing any construction contract, ask this question: "What happens if costs come in higher than the estimate?"

If the answer is "you pay the difference," you have an open-ended contract. If the answer is "we absorb the difference," you have a fixed-price contract.

The structure of that answer tells you exactly how the risk of the project is distributed — and who is motivated to control costs.

Questions about how we price projects in Los Cabos? The first conversation is free.

Schedule a free consultation → info@symbioticarq.com