Designing the First Five Feet
Bioterra Amenity Terrace, San Diego, CA
How San Diego’s Zone 0 Requirements Are Reshaping Landscape Architecture
Written By
Adam Crowell, ASLA
Associate
Five feet does not sound like much.
On a large site, it may barely register. But on a dense infill project, podium courtyard, or residential site, five feet can represent a significant portion of the outdoor space available for planting, circulation, seating, stormwater infrastructure, and amenities.
Now imagine drawing a five-foot-wide band around every applicable building wall, and then reconsidering what can occur inside it. That is one of the challenges created by the City of San Diego’s new Zone 0 requirements. Intended to reduce the vulnerability of structures to wind-driven embers during wildfires, Zone 0 establishes an ember-resistant area within the first five feet of a structure. San Diego Fire-Rescue identifies combustible vegetation and materials immediately adjacent to buildings as an ignition risk. For landscape architects, however, Zone 0 is more than a restriction on foundation planting. It creates a new spatial layer that overlaps with existing requirements for landscaping, common open space, trees, accessibility, stormwater, screening, irrigation, utilities, and outdoor amenities.
How do we create meaningful outdoor environments when the same limited space is expected to be planted, usable, accessible, water-conscious, and ember resistant?
What Is Zone 0?
Within the City of San Diego, Zone 0 generally extends five feet horizontally from the exterior wall of a structure. For purposes of San Diego Fire-Rescue Standard D-2, the measurement can also extend from attached decks, stairs, and pergolas, including self-supporting versions located within one foot of the occupied structure. Noncombustible patios are treated differently under the standard.
The current requirements apply to new structures and additions in the City’s Very High Fire Hazard Severity Zones that have applied for a building permit on or after February 28, 2026. Additions that increase a building’s footprint by more than 50 percent must establish Zone 0 compliance for the entire structure; smaller additions follow the guidance applicable to existing portions of the structure. The City states that existing structures are expected to comply beginning February 28, 2027.
It is important to note that this article focuses on the City of San Diego’s implementation of Zone 0. Other jurisdictions and fire districts within San Diego County implement state requirements differently. The statewide regulatory picture is also continuing to develop. As of August 13, 2026, the California Board of Forestry and Fire Protection continues to consider statewide Zone 0 regulations. Project teams should confirm the latest state and local requirements before relying on any specific implementation date or technical provision.
Zone 0 Does Not Necessarily Mean Zero Plants
One of the easiest misconceptions about Zone 0 is that the first five feet must be completely devoid of vegetation. San Diego’s standard is more nuanced.
Combustible mulch and wood chips are prohibited, vegetation must be fire-smart and permanently irrigated, and plants cannot be located within two feet of windows, vents, doors, or other building openings. But limited planting is still possible. Nonwoody groundcovers less than three inches tall are permitted, while small areas of nonwoody herbaceous planting up to 18 inches tall may be allowed when they meet prescribed area and separation requirements. Small plants may also be used in movable, noncombustible pots under specific size, height, and spacing limitations. Podium projects receive an additional consideration: large potted plants may be permitted on exterior podium levels when maintained at prescribed distances from adjacent exterior walls and building openings.
Trees introduce another layer of complexity. New trees must maintain horizontal separation from adjacent trees and must be located and maintained so their mature drip lines remain away from combustible structures. Exceptions exist for certain noncombustible Type I, II, and IV structures and, under defined conditions, for approved street trees. That exception is particularly important for design teams. Whether a tree works in a courtyard may depend not only on its species and mature canopy, but on the building’s construction classification and the location of nearby openings. A landscape decision can therefore depend on architectural information much earlier than it traditionally has.
Zone 0 also affects the material and furnishing palette. New fences and gates within the zone must use noncombustible materials such as steel, aluminum, concrete, or masonry, while fire-retardant-treated wood is limited to specific conditions. Suddenly, what began as a vegetation-management requirement is influencing privacy screens, trellises, gates, fences, shade structures, and the overall architectural character of an outdoor space.
When Five Feet Collides with the Rest of the Code
For landscape architects, the challenge with Zone 0 is not simply determining what is allowed within the first five feet of a building. The greater challenge is that those same five feet may already be expected to satisfy several other site and landscape requirements.
San Diego’s landscape regulations require many developments to provide minimum planting areas, achieve required plant points, incorporate trees, and create usable common open space. At the same time, projects must accommodate accessible circulation, stormwater infrastructure, utilities, building access, screening, irrigation, and other site-specific constraints. Zone 0 adds another layer to that already crowded framework.
For development with five or more dwelling units, Section 142.0405 provides several methods for satisfying remaining-yard and common-open-space landscaping requirements. One method requires planting within at least 30 percent of the area located within a ten-foot offset from the structural envelope. Another allows common open spaces such as plazas, paseos, and courtyards to provide planting within 20 percent of each common-open-space area, together with the applicable plant-point requirements.
Zone 0 creates a direct spatial relationship with these standards. Half of the ten-foot structural offset falls within the five-foot ember-resistant zone, where the type, height, spacing, and location of vegetation are substantially more restricted. The requirements are not necessarily incompatible, but satisfying both can become more difficult, particularly on compact sites where there is little flexibility to relocate required planting.
Tree requirements introduce a similar challenge. San Diego’s landscape regulations generally require at least half of the required planting points to be achieved with trees. Zone 0, meanwhile, establishes limitations on the proximity of new tree canopies to combustible structures and adjacent tree crowns. On dense infill projects, viable locations for required trees may therefore become limited precisely where canopy, shade, and visual relief are most valuable.
San Diego State University - Topaz Student Housing
The effects extend beyond planting. Areas immediately adjacent to a building often serve multiple purposes: pedestrian circulation, accessible routes, building entrances, drainage, utility access, outdoor seating, privacy screening, or transitions between indoor and outdoor spaces. Traditional landscape responses—such as planting against blank walls, vine-covered trellises, wood fencing, or dense screening—may no longer be appropriate within Zone 0. This is what makes the new requirement significant from a design standpoint. Zone 0 does not replace the landscape, open-space, accessibility, or stormwater standards already governing a project. It must be layered on top of them.
The result is less a single code conflict than a spatial coordination exercise. Every requirement may be reasonable on its own, but when several of them occupy the same limited portion of a site, the landscape architect must determine how that space can perform multiple functions without compromising fire safety, usability, or the overall quality of the outdoor environment.
Podium Courtyards: Where the Conflict Becomes Visible
Parco - National City
Podium courtyards may be one of the clearest examples of Zone 0’s design impact because their boundaries are fixed. A courtyard cannot simply expand outward to make room for another setback. Planters already compete with structural loading limitations, waterproofing, drainage, irrigation, accessible routes, building openings, and required amenity areas. Zone 0 adds another geometry to that puzzle.
Doors, windows, and vents create additional planting constraints. Attached stairs and pergolas may shift where the five-foot measurement begins. Large pots need appropriate setbacks. Tree placement may depend on the building’s construction type. Meanwhile, landscape planting percentages and plant-point requirements may still apply. For project teams, this means Zone 0 cannot wait until construction documents. By then, the courtyard dimensions, architectural openings, structure, waterproofing, and amenity program may already be fixed.
The five-foot line should instead appear during concept design alongside accessible routes, planting calculations, stormwater areas, utilities, tree locations, outdoor kitchens, lounges, fences, gates, and shade structures.
For example, McCullough is currently working with the architecture firm JWDA on a project located within the City’s “Very High Fire Hazard Severity Zone”, where a courtyard is intended, in part, to satisfy common open space planting requirements. Applying Zone 0 to that space has required the design team to look beyond whether the courtyard simply meets dimensional and planting standards. The more important question is how the space continues to function once fire-resistance requirements are layered into the design. In this case, the location of planting, shade, furnishings, and other landscape elements must be reconsidered together so the courtyard remains both code-compliant and successful as a usable outdoor space.
Designing the Five-Foot Band Rather Than Leaving It Empty
The Gardens Casino - Hawaiian Gardens
The most successful response to Zone 0 may be to stop thinking of it as leftover space.
A five-foot building apron can become an intentional element of the landscape through concrete, unit pavers, porcelain paving, stone, appropriate gravel in noncirculation areas, drainage bands, accessible circulation, or noncombustible seat walls and architectural edges. Changes in paving pattern, scale, texture, or jointing can visually integrate the zone into the broader landscape without disguising its fire-protection function.
At the same time, substantial planting can be consolidated beyond Zone 0 rather than distributed as narrow foundation planting along every building wall. Larger planting masses can create central courtyard gardens, planted islands, groves, and more generous soil volumes. This may result in less vegetation immediately against the architecture but a stronger landscape overall.
Where appropriate, permitted low planting can soften the transition between hardscape and the primary landscape. The goal does not need to be filling every technically available square foot with vegetation. A few carefully located planting pockets may be more effective than forcing planting into every available gap.
San Diego Municipal Code also contains existing flexibility that may become increasingly useful. Section 142.0405 allows excess plant points to reduce required planting area in certain circumstances, subject to limits. Its application should be confirmed with the project reviewer, but it illustrates an important point: solving new-code conflicts may require a deeper understanding of flexibility already embedded elsewhere in the code.
A More Integrated Design Process
Zone 0 ultimately changes more than planting plans. It changes coordination.
Landscape architects may need information about construction classification, building openings, vents, eaves, attached structures, and Wildland-Urban Interface compliance much earlier in design. Architects may need to understand how small shifts in a door, wall, or pergola affect planting and tree opportunities outside. But that conversation should extend beyond the arrangement of the building to how the building itself is constructed.
For architects and developers, fire resilience can also mean reconsidering material choices and construction systems, particularly in areas with elevated wildfire risk. Many projects continue to rely heavily on combustible wood-framed construction, while more fire-resistive or noncombustible assemblies may provide opportunities to reduce vulnerability at the building itself. Zone 0 addresses the conditions immediately surrounding a structure, but it is only one part of the solution. A more comprehensive approach considers the landscape, the building envelope, construction type, exterior materials, openings, and other architectural decisions together rather than relying on the first five feet of the site to carry the full burden of fire protection.
Civil engineers may need to coordinate stormwater facilities with ember-resistant areas. Property managers must understand that permanent irrigation, pruning, plant height, separation, and removal of dead material become part of maintaining compliance over time. Fire resilience therefore becomes a shared responsibility across disciplines and throughout the life of the project.
When two requirements appear to compete for the same space, the best solution may be to diagram the overlap early and discuss it with Development Services and Fire-Rescue rather than waiting for plan check to expose the problem.
Draw the five-foot line. Overlay the required planting. Add the building openings. Add the accessible route. Add the stormwater system, utilities, trees, amenities, and shade.
The conflicts become much easier to solve when they are visible.
The First Five Feet as a Design Opportunity
Zone 0 will undoubtedly make some San Diego projects more difficult to design. Traditional foundation planting may disappear in certain locations. Trees may need to move. Wood screens and trellises may give way to new material palettes. Small courtyards may require a more deliberate balance between planting, hardscape, shade, circulation, and usable space. But difficulty does not have to mean diminished design.
In many ways, Zone 0 asks designers to reconsider habits that have become automatic. Instead of placing planting against every building edge, we may create stronger and more intentional planting zones. Instead of relying on wood screens, fences, and trellises, we may explore new materials and architectural expressions.
Instead of treating the landscape as something that fills the space left over after the building is designed, we may be pushed toward earlier and more meaningful coordination between architecture, landscape architecture, fire protection, civil engineering, and development.
That shift can ultimately make projects better. Constraints often force designers to be more deliberate about what a space is doing and why. The first five feet can become circulation, a building apron, a drainage zone, a seating edge, an extension of the architecture, or simply intentional negative space that allows the planting beyond it to feel more substantial. Trees and larger planting areas may become more concentrated, but they can also receive better soil volumes, stronger spatial relationships, and greater visual importance. The result does not have to feel like a landscape with something taken away. It can feel like a landscape that has been edited with greater purpose.
Zone 0 should also remind us that wildfire resilience cannot be solved by landscape regulations alone. The landscape, building envelope, construction type, exterior materials, openings, maintenance practices, and long-term management of a property all contribute to how a project responds to fire. The five-foot zone is one tool within a much larger design problem. The most resilient projects will be those in which every discipline takes responsibility for that problem rather than expecting one portion of the site to solve it.
For landscape architects, this is an opportunity to expand our role. We are being asked to understand fire behavior, construction systems, code relationships, maintenance, and building design more deeply, while still creating places that people want to inhabit. That is not a limitation of the profession; it is an evolution of it.
The first five feet may look different than they did before, but they do not have to be empty, sterile, or forgotten. If we approach Zone 0 as a design parameter rather than an obstacle, it can push us toward landscapes that are more coordinated, more intentional, and ultimately more resilient.
“Good design has always been about responding creatively to constraints. Zone 0 is simply a new one – and how we choose to work with it will shape the next generation of San Diego’s designers.”
Sources & Reference Documents
The following sources informed the rough draft. Confirm that each remains current before publication:
• San Diego Fire-Rescue Department — Standard D-2: Zone 0 Requirements for New Structures
• City of San Diego Municipal Code — Chapter 14, Article 2, Division 4: Landscape Regulations
• City of San Diego Municipal Code — Chapter 13, Article 1, Division 4: Residential Base Zones
• California Board of Forestry and Fire Protection — Defensible Space Zones 0, 1, and 2
Editorial note: This article reflects City of San Diego requirements and available state rulemaking information as of August 2026. Requirements, fire-hazard maps, agency interpretations, and statewide regulations may change. Project teams should confirm current requirements and obtain project-specific direction from the applicable reviewing agencies.
