Are Engineers Over-Designing Your Home?

Why this matters

One Redditor recently wondered why a structural engineer specified a massive footing for a simple porch. The contractor said it was overkill and questioned the cost. This tension is common: clients see concrete and rebar costs rising and assume engineers are being conservative to cover themselves. But there is a difference between prudent safety margins and true over-engineering.

Safety factors exist for a reason. Codes are calibrated around uncertainty: materials vary, loads vary, soil reports have limits, and the real world is never as clean as a spreadsheet. Structural codes are designed around reliability targets and probability, not perfection.

Where cost creep happens is not usually one egregious decision. It is compounding conservatism. Multiple parties each add a margin, often without visibility into what the other discipline already assumed. The Institution of Structural Engineers has published guidance specifically aimed at preventing unnecessary strengthening by making safety factor decisions more explicit and consistent.

What we are seeing

Codes set minimums, not maximums. Building codes define the lowest acceptable standards. Engineers must meet or exceed these, but they have discretion in how conservative to be.

Compounding safety factors. Each discipline can add its own margin. Structural, geotechnical inputs, materials, energy assumptions, and MEP loads all interact. Without clear coordination, small buffers can stack into real material and schedule cost.

Fear of liability. Engineers are legally responsible for their designs. Risk-averse consultants may oversize elements to preempt challenges, especially when communication with builders is poor and assumptions are not clearly stated in the set.

How a great engineer should approach it

A great structural engineer is not trying to be aggressive. They are trying to be clear.

The best work usually has three traits:

Transparent assumptions. A strong set makes the governing assumptions easy to find and easy to audit. The goal is not fewer safety factors. The goal is making sure the safety factors are intentional, not duplicated.

One consistent story across the whole package. Over-design often starts when the set tells different stories in different places. Notes say one thing. Details imply another. Calculations assume something else. A great engineer tightens the narrative so the reviewer can verify intent without guessing.

Coordination before concrete. The right time to remove waste is before the details harden. That includes checking load paths, equipment locations, and scope boundaries early so structural decisions are not compensating for late changes in MEP or energy.

AI supports the workflow. Licensed engineers own the decisions, review, and stamp.

At Spacial, this is the promise we hold ourselves to: one engineering partner for structural engineering, MEP engineering, and energy efficiency, delivered as a coordinated, permit-ready set that is reviewed and stamped by licensed engineers.

Why this matters to you

If you are building a home, you want a structure that is safe, compliant, and cost-effective. Over-engineering does not make a house safer after a point. It just makes it more expensive.

At Spacial, we deliver coordinated designs that aim for the sweet spot between code compliance and efficient material use. We do that by pairing AI with licensed engineers. The result is engineering that is the right size for the project, not just the most conservative interpretation of disconnected assumptions.