Office site plans and office re-planning

What an office site plan carries

An office site plan places the building, the parking field or deck, drive aisles, fire lanes, loading, the generator and trash yards, and any pads or later phases on the parcel, then proves the program in a site data table. For office, the table that decides approval and financing carries: gross acreage; zoning district and FAR against the cap; building gross square feet and floorplate size; parking required against parking provided, stated as a ratio per 1,000 SF; accessible and van-accessible stalls; EV spaces where the state requires them; setbacks; and the aerial fire access lane wherever the roof sits more than 30 feet above grade ^[3]. The preliminary site plan stops short of engineering: utility service sizing, stormwater design and grading are added by your engineer of record, who builds the sealed set on the layout.

The market decides which office plans get drawn at all. CBRE counted 1.3M SF of US office completions in Q1 2026, the lowest quarterly total since it began tracking in 1990, with overall vacancy at 18.6 percent against 12.7 percent for prime space ^[6]. New office still pencils in three places: medical office, government and credit-tenant build-to-suit, and trophy space in supply-constrained submarkets ^[6]. Medical office absorption reached about 19M SF across the top 100 markets in 2024, up 15 percent year over year ^[7]. Most of the remaining work is re-planning: obsolete office parks and campuses re-entitled for housing, industrial, data centers and mixed use. This page treats the re-plan as seriously as new construction.

Office layout archetypes

Five layouts cover nearly every office site plan. The FAR figures are generalized ranges, not code values; the local zoning code sets the cap on a specific site.

Medical office is the office type with a growth case. On-campus medical office buildings are 150 percent larger than off-campus properties because physicians prefer hospital proximity for reimbursement, while off-campus buildings follow rooftops into growing suburbs ^[8]. The small-bay flex park overlaps with the flex space site plan hub, which carries the bay and truck standards.

Design standards that shape an office layout

Every standard below moves the building, the parking or the fire lane.

Parking ratios are falling, but entitlement math still runs on legacy minimums in most suburban codes. NAIOP's survey of suburban developers found 4.0 per 1,000 SF the single most common leasing ratio, chosen by 46 percent of respondents ^[9]. Where the code allows it, a transit-adjacent infill site can defensibly go to 1.6 per 1,000: the Civica project in Cherry Creek, Denver, adhered to that ratio with 215 spaces ^[1]. Where the zoning minimum sits above real demand, a shared parking study is the lever. The accepted method is Shared Parking, 3rd Edition, published in March 2020 by ULI, ICSC and the National Parking Association: establish stand-alone peak demand per use, apply hourly presence factors from 6am to midnight, then apply transit and internal-capture adjustments. Jurisdictions accept it as a starting point, often through proffers that require periodic re-checks of the shared supply ^[13]. National ratio comparisons are on the blog in parking ratios by asset type.

Land value, not preference, decides surface against structured parking. A surface stall runs about $3,000 to $8,000 and consumes 300 to 400 SF including drive aisles; an above-grade garage runs $18,000 to $35,000 per space and underground $25,000 to $50,000 ^[10]. Structured parking pencils only when land value per buildable square foot exceeds that structure cost spread across the land a surface stall would consume ^[10]. In transit-oriented and urban settings, ULI documents structured costs of $19,000 to $75,000 per stall ^[14].

Fire access is the hard driver for any mid-rise office. Where the roof sits more than 30 feet above grade, the International Fire Code requires an aerial apparatus access road at least 26 ft wide, positioned 15 to 30 ft from one entire side of the building and parallel to it, with no overhead power lines. Buildings over 62,000 SF gross need two separate access roads, or one road up to 124,000 SF if fully sprinklered ^[3]. That lane fixes the building against the parking field before anything else is drawn.

Floorplate depth and the conversion screen

Floorplate depth is the most decisive variable for both office efficiency and conversion. Efficient modern office plates run 25,000+ SF with core-to-glass depths of 40+ ft, which maximizes leasable area and makes residential conversion very hard ^[4]. Housing needs the opposite: the ideal double-loaded corridor floorplate is 68 to 70 feet deep, and unit depth caps at roughly 30 to 35 ft to the window ^[4]. Massing decisions made at ground-up design lock in, or rule out, conversion decades later.

The numbers work only on a low basis. CBRE estimates conversion and renovation at $100 to $500/SF, and New York developers report $300 to $500/SF ^[17]. Purchase plus conversion averages $685/SF, against $600/SF to buy existing multifamily and $588/SF to build new ^[18]. Goldman Sachs found office acquisition prices would need to fall almost 50 percent for conversion to be financially feasible in the top remote-work metros ^[19]. Unit layouts, interiors and the renderings that sell a conversion sit with commercial interiors and conversions and apartment rendering; the blog's Class B office to multifamily calculator and office to life science posts cover the market side.

Re-planning obsolete office parks and campuses

Office land is repricing hard. About 600 office buildings, over a third of 2024 sales with a known value, traded below their prior value, up from 386 in 2023 ^[20]. CBD office values fell about 50 percent peak to trough, against about 19 percent for suburban office ^[21]. The counter-signal is narrow and contested: Yardi Matrix reported national office values up 6.1 percent in 2025 to $182/SF, still 32.7 percent below the 2019 average of $271/SF, and the CBD decline data above limit any recovery to prime space in concentrated markets ^[22]. Many suburban campuses now appraise near land value in an alternative use. The re-plan proves that value: subdivide the campus, test housing, industrial, data center and mixed-use scenarios, and draw the one the zoning can be moved to.

Johns Creek sits in the Atlanta metro and Court Arcade in Charlotte. Where the re-plan lands on warehouse or outdoor industrial, the industrial site plan hub carries the truck court and dock standards; where it lands on for-sale lots or townhomes, see single-family and townhome site plans.

Re-entitlement runs through five tools: a PUD amendment (a major change follows the same process as a rezoning; a minor change is administrative), a rezoning of the legacy office-park district, a comprehensive plan amendment where the new use conflicts with the future land use map (especially on parcels over 10 acres), an adaptive reuse ordinance, or a by-right conversion pathway. Timelines run from 6 months on Boston's streamlined conversion path to 18+ months for a full rezoning plus comprehensive plan amendment ^{[28, 29]}.

Staff reports document the opposition: traffic, school capacity, neighborhood character and building height, and loss of municipal tax base; industrial re-plans draw noise, stormwater runoff and truck-traffic objections ^[29]. The reverse also happens. New Berlin, Wisconsin, amended its comprehensive plan in July 2026 to drop the residential element and rezone to industrial and PUD to protect Rockwell Automation's expansion ^[30]. Municipalities sometimes resist housing in office parks to keep commercial tax base and avoid school costs, so the site data table should answer both questions before the hearing.

Conversion incentives are concentrated in a few places:

Los Angeles adds a citywide Adaptive Reuse Ordinance with zoning incentives and streamlined procedures.

Re-planning an office site to mixed use

When a campus or downtown re-plan lands on mixed use, four sets of rules draw the plan: what the ground floor must hold, how parking is shared between uses, what state law now allows by right, and how a podium separates from the building above. The asset-level rules are in mixed-use site plans.

Ground floor. SeaTac, Washington requires at least 50% of the street-facing ground floor length, excluding vehicle entrances, to be designed for retail, commercial or service use, at an average depth of 30 ft and a minimum of 15 ft ^[36]. New York City requires 50% transparency between 2 and 12 ft on qualifying ground floors, with no blank segment over 10 ft (ZR 37-34) ^[37]. Seattle's commercial zoning summary, which the city labels illustrative, shows a 13 ft minimum ground-floor height and 60% transparency between 2 and 8 ft in its NC zones ^[38].

Shared parking. Published shared parking tables all use one method: multiply each use's required spaces by the percentage for each time period, sum each column, and take the highest column as the requirement ^{[39, 40]}. Office is the use that empties at night, which is what makes a re-plan with housing share well. Alexandria counts office at 100% on weekdays and 5% on weekday evenings and weekends, against residential at 60% on weekdays and 100% on weekday evenings ^[39]; Lynnwood counts office at 100% by day, 20% in the evening and 5% at night, against residential at 60%, 100% and 100% ^[41]. Some codes cap what staff can approve: Phoenix lets its traffic engineer grant up to a 15% reduction under the city's shared parking model ^[42], Clayton County, Georgia lets the Zoning Administrator approve up to 25% with inter-parcel access ^[40], and Hamilton Township, Ohio caps sharing at 50% of required spaces and requires a recorded agreement before a zoning certificate issues ^[43].

Percentages of each use's stand-alone requirement ^{[39, 41]}.

State law that moves the re-plan.

• Texas. SB 840, effective September 1, 2025, gives owners a by-right path to convert office, retail or warehouse buildings at least five years old to residential or mixed-use residential, and no zoning change or variance may be required for a qualifying project ^[44]. It applies only in a city of more than 150,000 people that lies wholly or partly in a county of more than 300,000 (Local Government Code Sec. 218.002) ^[45]. Density is 36 units per acre minimum, higher where the city allows more ^[46]; mixed-use residential means at least 65% of the square footage is residential ^[47]; and a city may no longer require a multifamily project in a mixed-use zone to include nonresidential uses ^[44].
• Florida. The Live Local Act requires multifamily and mixed-use residential to be allowed in commercial, industrial and mixed-use zones where at least 40% of the rental units stay affordable for 30 years, with administrative approval (Fla. Stat. 166.04151(7)) ^[48]. Under SB 1730 (2025) the required parking reduction is 15%, and parking is eliminated for mixed-use residential in a transit-oriented development area ^[49].
• Washington. ESSB 5184 (2025) caps required parking at 2 spaces per 1,000 SF of commercial space and 0.5 per multifamily unit, and bars minimums for commercial spaces under 3,000 SF, for ground-level commercial in mixed-use buildings and for changes of use ^[50].
• California. Gov. Code 65863.2 bars minimum parking requirements within one-half mile of a major transit stop, effective January 1, 2023 ^[51].

Podium. Where the re-plan stacks housing over a commercial or parking podium, IBC 510.2 (2024) treats the podium and the building above as separate buildings for area, stories and construction type when the horizontal assembly is 3-hour rated, the building below is Type IA, and shaft and stair enclosures through it are rated 2 hours ^[52]. NFPA 13 sprinklers are required below the assembly, and height is measured from grade plane ^[53], so the aerial access road the IFC requires above 30 ft still runs along one long face of the whole building ^[3].

Office to restaurant conversions: the San Antonio pattern

A smaller re-plan converts an office or retail suite to a restaurant. San Antonio shows how the rules stack; the full model project, with its approval table, is office or retail to restaurant conversion in San Antonio, and the interior plans and renders sit with commercial interiors and conversions. Rules are as of October 10, 2026.

The concept floor plan, the occupant and egress diagram, the patio plan and the interceptor siting are preliminary work; the design professional's permit set adds the sized plumbing, the hood and the certified occupant numbers ^[54].

Approval path for an office site

New office on correctly zoned land runs from concept review to site plan review to building permit. A re-plan adds the legislative step first, which is where the 6 to 18+ month range comes from ^[29].

Most states require an architect's seal on commercial building plans, with narrow small-building exemptions, and civil and site engineering (grading, utilities, stormwater) typically requires a PE seal regardless ^[65]. The seal triggers below are general rules; the state board, the building's size and occupancy, and whether the work is architectural or civil decide them on a live project.

Building performance standards also change the hold-or-re-plan math for older buildings. As of July 2026 they bind in roughly 16 active jurisdictions: New York City's Local Law 97 charges $268 per metric ton of CO2e over the annual cap for buildings over 25,000 gross SF; Boston's BERDO 2.0 fines of $1,000 a day began in 2025 for buildings over 35,000 SF; and Colorado, the first state-level standard for commercial buildings, set a June 1, 2026 Tier 1 compliance deadline ^[66].

What the engineer of record adds

The preliminary plan reserves the space; your engineer of record sizes what goes in it.

• Electrical service. Code minimums start at 3.5 VA/SF for office lighting (NEC Table 220.12) plus 1 VA/SF of receptacle load where the count is unknown ^[67]. EV loads can push a building's service from 2,000A to 3,000A+, changing transformer and switchgear sizing.
• Data center re-plans. ASHRAE Standard 90.4 applies above 20 W/SF power density and 10 kW of IT load, with typical heat density of 50 to 150 W/SF ^[68]. An office-to-data-center re-plan demands massive service upsizing.
• Stormwater. Surface parking is the dominant impervious-cover driver. Structured parking shrinks the footprint and the detention it needs, and underground detention can sit beneath structured decks, so a re-plan from surface-heavy office to structured mixed use often improves the stormwater profile.
• Generators. Required for life-safety egress lighting and, in medical office, for essential electrical systems (NFPA 110/99). The generator yard needs screening, fuel storage setbacks and acoustic treatment, and it conflicts with parking and fire lanes, so it is sited early.

Lenders and appraisal reviewers ask for a defined package on an office site or re-plan: an ALTA/NSPS survey; a sealed site plan with the parking count and ratio calculation; a shared parking study if parking is reduced; an ADA compliance plan; a fire access plan showing IFC Appendix D aerial access for buildings over 30 ft; a stormwater concept with detention sizing; utility availability letters and service-sizing calculations; a phasing plan; a zoning and entitlement memo; and, for re-plans, a highest-and-best-use study comparing scenarios. The preliminary site plan supplies the layout, the counts, the phasing and the scenario plans. The surveyor, the engineer of record and your consultants supply the sealed and calculated items on top of it. The difference between the two stages is set out in preliminary versus final site plans.

Related site plans and guides

Office re-plans often produce pads for other uses: retail center site plans cover inline shops and outparcels carved from surplus parking, and hotel site plans cover the hotel pad in a mixed-use re-plan. For the basics, read what a site plan is. Exterior and aerial views tied to the plan come from 3D rendering services. For the vacancy backdrop, see office vacancy and hybrid work.