Smaller, Smarter, Safer: The Architectural Case Against the McMansion in Fire-Prone Regions

Barbara Bestor, one of the most prominent architects working in the Los Angeles post-fire recovery, put the post-fire housing question in a way that cut through a lot of the technical debate: 'The best big-picture thing right now is a tilt away from McMansions. For actual people rebuilding their house, what do they really need?'

That question is the right one. And the answer, when you work through it from both an architectural and a fire engineering standpoint, is consistently that smaller, more carefully designed homes perform better in WUI fire environments, cost less to maintain, and serve their owners more effectively over the long term than the oversized homes that dominated the development patterns in the neighborhoods that burned.

This isn't just an aesthetic or lifestyle argument. It's a fire physics argument with architectural implications. It's also a financial argument that's increasingly hard to ignore in a market where insurance for large homes in fire-prone zones is either unavailable or unaffordable.

1. The Fire Physics of Building Size

A larger building has more exterior surface area. More exterior surface area means more potential contact area with radiant heat from a passing fire and more surface available for ember landing. A 5,000-square-foot home has roughly double the exterior wall area of a 2,500-square-foot home, which means double the area that needs to be defended from radiant heat and ember intrusion.

The relationship between building size and fire risk isn't perfectly linear. The geometry matters as much as the area. A compact square floor plan has significantly less exterior surface area per square foot of living space than a sprawling L-shaped or U-shaped plan. Simple roof forms with minimal valleys, ridges, and intersecting planes accumulate far fewer embers than complex roof designs with multiple planes, dormers, and decorative elements. Deep overhangs that are common in craftsman and contemporary designs create sheltered zones where embers collect and smolder.

This is why fire engineers and WUI-experienced architects consistently point to building simplicity as a fire resilience strategy. It's not that a simple building is automatically safer. It's that a simple building offers fewer opportunities for ember accumulation, fewer vulnerable interface zones between materials, and fewer complex details that are hard to protect adequately.

16,000+

Structures destroyed in the 2025 Los Angeles wildfires. The vast majority were conventionally framed, larger homes in neighborhoods where material and design complexity, not structural failure, was the primary vulnerability.

2. What Compact Design Actually Means Architecturally

Compact doesn't mean cramped. The most interesting design work coming out of the post-fire recovery conversations is about how to achieve the same quality of living experience in a smaller, more efficient envelope. That's a different design problem than simply shrinking a larger house, and it produces different results.

Program efficiency: what do you actually need?

Most American homes are built with a program that reflects assumptions about how space will be used that often don't match how people actually live. Formal dining rooms that are used four times a year. Guest bedrooms that sit empty most of the time. Living rooms and family rooms that serve nearly identical functions. Compact design starts with an honest accounting of how the household actually uses space and designs to that, rather than to a conventional checklist.

In post-fire rebuilding contexts, this conversation is made easier by the fact that homeowners have often been living elsewhere during a rebuild period and have a clearer picture of what they actually needed versus what they had. Some of the most thoughtful rebuild projects coming out of the 2025 fires are homes that are substantially smaller than what was there before, not because the owner couldn't afford to rebuild at full size, but because they decided they didn't need to.

Section and volume: doing more with less

Architecturally, compact homes that feel generous often achieve that through section design: higher ceilings in key living areas, clerestory windows that bring daylight deep into the plan, indoor-outdoor connections that expand the effective living area, and interior volumes that vary to create spatial interest without adding floor area. A 1,800-square-foot home with a well-designed section can feel larger than a 2,400-square-foot home with flat ceilings and a conventional floor plate.

This is standard architectural practice in good residential design. It's worth noting explicitly in the post-fire context because the default pressure in residential development is toward more square footage. The cost-per-square-foot economics of construction often look more favorable at larger sizes, which pushes developers and builders toward larger homes even when smaller ones would serve their buyers better. Pushing back on that logic, and designing smaller homes that are genuinely more livable than larger ones, requires explicit architectural intention.

Material efficiency and the fire resistance connection

Compact, simply detailed homes are also easier to build to WUI code compliance standards. A straightforward gable or shed roof with no valley intersections is easier to flash and seal completely than a hip-on-hip roof with three dormers and a skylight. A wall assembly with a single cladding type and continuous runs between openings is easier to detail without gaps than a wall with multiple materials, decorative elements, and complex transitions.

The connection between architectural simplicity and fire resilience isn't coincidental. Both derive from the same principle: fewer interface zones, fewer opportunities for failure. The architectural decision to simplify a roof form or eliminate a complex material transition is simultaneously an aesthetic decision and a fire engineering decision.

3. The Insurance and Financial Reality

The practical financial case for smaller homes in fire-prone zones has been made decisively by the insurance market. California's insurance crisis has hit large homes in fire-prone zones harder than small ones for a simple actuarial reason: a larger home costs more to replace, so its fire insurance exposure is higher. In a market where insurers are rationing coverage capacity in WUI zones, they preferentially restrict or exit coverage for the highest-value exposures first.

A homeowner rebuilding in the Palisades in 2026 faces a dramatically different insurance landscape than the one that existed when their home was built. The FAIR Plan, California's insurer of last resort, has policy limits that may not fully cover the replacement cost of a large home. Private market coverage for WUI properties in the highest-risk zones is either unavailable at any price or available only with deductibles and exclusions that substantially reduce its value. Building a smaller home means a smaller replacement cost exposure, which makes the insurance problem more manageable regardless of what the market does.

For Developers Building in WUI Zones

The market signal is clear: smaller, simpler, more fire-resilient homes are both easier to insure and more attractive to buyers who understand the insurance landscape. Developers who lead with WUI compliance, compact design, and documented fire resilience in their marketing are differentiating themselves in a market where those attributes are increasingly decision-critical. The buyer who lost a 4,000-square-foot home in the Palisades and is rebuilding at 2,200 square feet isn't making a sacrifice. They're making a rational decision about what they actually need and what they can practically insure and maintain.

4. Case Study Houses and What They're Teaching

Two case study house programs launched in the aftermath of the 2025 fires are producing some of the most closely watched residential design work in the WUI context. The Case Study: Adapt program and the UCLA CityLAB Small Lots, Big Impacts pilot are both explicitly focused on rethinking residential design in fire-prone communities: smaller footprints, fire-resistant materials, efficient programs, and designs that can be replicated at scale.

What's notable about both programs is their focus on replicability. The architectural lesson from the fires isn't just about individual award-winning projects. It's about design approaches that can be systematized, permitted efficiently under expedited processes, and built by contractors who are already familiar with the system. That's a different design brief than a custom single-family home commission, and it's producing genuinely different design thinking.

The most practical insights from these programs so far: concrete slab-on-grade foundations with protected stem walls reduce the vulnerability at the base of the building. Non-combustible or ignition-resistant cladding running full height without gaps at foundation and soffit eliminates one of the most common ignition pathways. Roofline simplicity reduces ember accumulation zones. And floor plans that treat the outdoor living area as a designed extension of the interior, managed as part of the defensible space, produce homes that perform better in fire scenarios while feeling more connected to the landscape.

Conclusion

The post-fire pressure to rebuild quickly and at full scale is real. It comes from homeowners who lost their homes, from communities trying to recover their tax base, and from the political machinery around disaster recovery. But the opportunity that these fires created, to build smaller, smarter, and more fire-resilient homes in communities that have been devastated by exactly the vulnerabilities that better design could address, is one that deserves to be taken seriously.

The architectural case for smaller homes in fire-prone zones isn't a case for less. It's a case for better: more compact, more efficient, more carefully detailed, more fire-resilient, and more honest about what people actually need from the places they live.