The decision that costs the least to change is the one made in schematic design. A structural system reconsidered on the drawing board takes a morning. The same reconsideration after the permit set is issued takes weeks and money. Evaluated on site during construction, it can cost a significant portion of the project budget. Evaluating architectural options before construction is not cautious — it is efficient.
Why Options Must Be Compared, Not Proposed
A single design proposal presented to a client is a recommendation. The client can accept it or reject it. They cannot evaluate it, because they have nothing to compare it to. They may feel the proposal is correct, or they may feel it is wrong, but they cannot articulate why on any objective basis.
A comparison of two or three options against shared criteria is a decision tool. The client understands what they are choosing between. They can apply their program requirements, their cost sensitivity, and their aesthetic preferences to a structured matrix rather than reacting to a single image.
The matriz de opciones — the options matrix — is how MÉTODO presents decisions in schematic design. It is not a style choice. It is a methodology for producing decisions that the client participates in and understands.
The Four Questions an Options Matrix Must Answer
For any major architectural decision, the matrix must answer four questions before a direction is selected:
First: what does each option cost relative to the baseline? Not an absolute figure — design cost estimates at schematic phase are rough — but a relative index. Option A is the baseline. Option B is fifteen percent higher construction cost with a specific reason. Option C is ten percent lower with a specific trade-off. The client understands the cost implication without being given a number that will prove wrong in any case.
Second: what does each option require in maintenance over the design life? A building is occupied for thirty to one hundred years. The material choice that costs less to build may cost more to maintain. Painted stucco versus stone: lower upfront cost versus zero long-term maintenance cost. This trade-off should be visible in the comparison.
Third: what does each option produce spatially and thermally? This is where section drawings and sun path diagrams belong. The matrix cell is not filled with words — it is filled with a drawing that shows what the option produces in use.
Fourth: what is the reversibility of each option after construction? Some decisions — window placement, structural grid, patio position — are nearly irreversible after concrete is poured. Others — finish material, interior partition layout — can be changed with moderate cost. The matrix flags which decisions are irreversible. Those receive more thorough evaluation before selection.
Structural System Comparison: A Worked Example
In schematic design for a residential project, the structural system is typically the first matrix comparison. The structural system determines span capabilities, material character, thermal mass properties, and construction timeline.
A typical matrix for a Mexico City residence:
| System | Max span | Thermal character | Visual character | Cost index | Reversibility |
|---|---|---|---|---|---|
| RC frame with stone infill | 5 to 7 m | High mass if stone fills bays | Stone and concrete, warm | Baseline | None after curing |
| RC frame with concrete block | 5 to 7 m | Medium mass | Smooth or textured plaster | Minus 10 to 15% | None |
| Load-bearing stone | 4 to 6 m | Very high mass | Heavy, textured, honest | Plus 25 to 35% | None |
| Steel frame, stone or concrete panel fill | 8 m plus | Depends on infill | Industrial, precise | Plus 15 to 25% | None |
The client reviews this matrix before a structural concept is committed to. If the project has a budget constraint, Option 2 is a clear starting point. If the thermal performance and material character goals align with Option 3, the cost premium is evaluated explicitly, not discovered in the budget after the design is fixed.
Climate Performance Comparison
Climate performance decisions — wall assembly, glazing strategy, shading devices — are a second category of options that belong in schematic design and should be compared explicitly.
The trap in conventional practice is specifying climate performance at the construction document stage, when the section geometry is already fixed and the structural engineer has sized members. At that point, adding thermal mass or changing overhang depth requires redesign. In MÉTODO, climate performance is a schematic design decision — it shapes the section before the structure is specified.
For shading strategy on a south-facing glazed wall in Mexico City:
| Strategy | Solar control | Construction cost | Maintenance | Formal effect |
|---|---|---|---|---|
| Fixed concrete overhang | Excellent — depth calculated for latitude | Low — cast with structure | None | Horizontal, strong |
| Adjustable aluminum louvers | Excellent — user controlled | Medium | Annual — mechanism wear | Industrial, lighter |
| Exterior vertical fins | Moderate — effective for low sun angles | Medium | Low | Rhythmic, vertical |
| Interior blinds | Moderate — heat enters before blind blocks it | Low | High — replacement cycle | No exterior expression |
The fixed overhang dominates on cost and maintenance. But if the client requires full glazed exposure in winter without any horizontal projection — a view constraint, perhaps — the adjustable louver becomes the functional solution. The matrix makes this trade-off explicit.
Who Participates in the Evaluation
The matrix produces better decisions when the right people evaluate it. For a residential project, the client and the primary architect review the schematic design matrix together — not by email, but in a meeting where questions can be asked and section drawings can be explained.
The structural engineer participates in the structural system selection. The mechanical engineer participates in ventilation and climate performance decisions, if a mechanical system is involved. These consultants are brought in at schematic design, not after the structural system is fixed.
The sequence: analysis, alternatives, matrix comparison, decision. Not: analysis, proposal, revision, revision, revision.
Próximos pasos
If your project is in early design and your architect has presented a single direction without a comparison matrix, it is worth asking: what are the alternatives, and what would they cost? This is not an adversarial question. It is the question that produces better outcomes for everyone.
Conoce el método de MÉTODO to understand how we structure options evaluation in every phase of residential design.