Building a parking structure starts with defining how many vehicles it must accommodate, who will use it and which parking dimensions apply. The owner and project team must then coordinate the site, soil conditions, construction method, parking-bay layout, ramps, clear heights, structural grid, foundations, drainage, durability, safety and applicable codes.

These decisions should not be made independently. Parking geometry affects the structural system. The structural system affects the building weight, foundations, floor-to-floor height and construction sequence. Drainage affects floor slopes, joints and durability. The project-delivery method affects how early these decisions can be coordinated.

This guide explains how to build a parking structure in the order that the major decisions should generally be made.

In brief: Define the parking need, understand the site, compare the construction methods, establish the parking layout, coordinate the structure and foundations, design for water and salt, plan construction, and maintain the completed facility as infrastructure.

1. Treat the Parking Structure as Infrastructure

A parking structure may look like a relatively simple building, but its operating environment is demanding. Vehicles carry water, snow, ice, road salt and chlorides into the facility. Wind-driven precipitation enters through open façades. The top level may be exposed directly to sun, snow, rain and temperature changes.

At the same time, the structure must resist:

• Vehicle and pedestrian loads
• Snow and snow-drift loads
• Wind and seismic forces
• Vehicle impacts against barriers and columns
• Temperature changes and structural movement
• Repeated wetting, drying and freeze-thaw cycles
• Snow-removal equipment and winter operations
• Continuous use by the public

A parking structure must therefore function as several systems at once:

• A vehicle-storage system
• A vehicle-circulation system
• A pedestrian environment
• A structural system
• A drainage system
• A transportation asset
• A long-term operating and maintenance responsibility

This is why parking structures should be treated as infrastructure rather than as ordinary buildings. Durability, inspection and maintenance cannot be added near the end of design. They must influence the construction method, structural behaviour, drainage, materials and details from the beginning.

Owners who want a broader planning checklist can also review 30 Things to Know Before Building a Parking Structure.

2. Identify the Decisions That Affect Cost and Schedule

A small number of early decisions have a disproportionate effect on the project. Once the layout, structural grid and construction documents are substantially complete, changing these decisions becomes difficult and expensive.

Major early decisions include:

• The number and types of parking spaces required
• The users and vehicle types the structure must accommodate
• The parking stall and drive-aisle dimensions
• The construction method
• The building footprint and number of levels
• The parking-bay width and structural grid
• The clear height and floor-to-floor height
• The ramp and circulation arrangement
• Whether the structure will be open-air or enclosed
• The site access and traffic strategy
• The soil-bearing capacity and foundation strategy
• The intended service life and durability requirements
• The need for future horizontal or vertical expansion
• The amount of parking that must remain operational during construction
• The façade and architectural requirements
• The electrical capacity, EV charging and parking technology
• The project-delivery and procurement method
• The required opening date

These decisions form a chain:

Parking dimensions establish the parking bay. The bay influences the structural grid. The grid affects the construction method. The construction method affects structural depth, building weight, foundations, schedule and lifecycle requirements.

Owners should evaluate these relationships before fixing the architectural form or issuing prescriptive structural requirements.

3. Define What the Parking Structure Must Accomplish

Before drawing the structure, prepare a clear project brief. The brief should explain the operational problem the structure is intended to solve.

Establish the parking requirement

Determine:

• The total number of spaces required
• The projected opening-day demand
• The long-term parking demand
• The number of public, employee, resident, fleet and reserved spaces
• The required accessible spaces and access aisles
• The required EV charging and EV-ready spaces
• Bicycle and motorcycle parking requirements
• Short-term, pickup, delivery or passenger-loading spaces

A target stall count should not automatically become a fixed building size. The building area should result from an efficient layout that satisfies the parking requirement.

Understand the users

A hospital, airport, commuter station, residential development, university and stadium may each require 1,000 spaces, but they will not operate in the same way.

Ask:

• Who will use the structure?
• When will the busiest arrival and departure periods occur?
• Will users be familiar with the facility?
• Will large pickup trucks and sport utility vehicles be common?
• Will vehicles queue at gates, ticketing systems or security checkpoints?
• Will the structure operate continuously or only during defined periods?
• Does the parking generate revenue?
• Will people use the structure alone at night?
• Where do pedestrians need to go after leaving their vehicles?

Confirm whether all projected parking is required

Before constructing a large capital asset, review:

• Existing parking utilization
• Shared-parking opportunities
• Peak-period demand
• Transit availability
• Transportation demand management
• Potential future developments
• Whether additional capacity can be added in phases

A structure that can expand later may provide better value than building the entire projected capacity immediately.

4. Organize the Project Through an Integrated Design-Build Process

Parking structures are function-driven infrastructure. The parking layout, ramps, structural system, drainage and construction method should be developed before the architectural form is finalized.

Function establishes the essential geometry. Good architecture gives that geometry an appropriate form and civic presence.

This is not an argument against architectural quality. It is an argument against designing the exterior first and forcing the parking, structural grid and circulation into the space that remains.

Why isolated handoffs create problems

A conventional sequence may involve a parking layout being handed to an architect, the architectural design being handed to a structural engineer, and the completed documents being handed to a contractor for pricing.

That sequence can miss important interactions:

• The parking module affects the structural grid.
• The structural grid affects the construction method.
• The construction method affects structural depth and clear height.
• Building weight affects foundations and seismic forces.
• Ramp geometry affects building length and floor-to-floor height.
• Drainage affects floor slopes, joints and structural detailing.
• Component dimensions affect transportation and crane access.
• Construction phasing affects the site plan and temporary parking.
• The façade affects open-air classification and mechanical systems.

Why design-build is well suited to parking structures

An integrated parking structure design-build team can coordinate parking planning, architecture, engineering, estimating, manufacturing, logistics and construction before decisions are locked into the design.

Progressive Design-Build can be especially useful where the owner wants to select an integrated team early, develop the design collaboratively and establish the final construction price after the major risks and requirements are better understood.

Create a Basis of Design

Before detailed design begins, document the project’s Basis of Design. It should include:

• Owner and user requirements
• Applicable codes, standards and bylaws
• Parking dimensions
• Vehicle assumptions
• Site and traffic assumptions
• Design loads
• Clear-height requirements
• Durability and service-life objectives
• Structural-method assumptions
• Drainage strategy
• Accessibility requirements
• Security and CPTED objectives
• Electrical and EV requirements
• Future-expansion requirements
• Budget and schedule targets

The Basis of Design should be updated as decisions are confirmed.

5. Compare the Three Main Parking Structure Construction Methods

Owners planning an above-grade parking structure will commonly compare three principal construction methods:

1. Cast-in-place concrete
2. UHPC panel-and-beam
3. Precast double-tee

UHPC panel-and-beam should be evaluated in the same category as cast-in-place and precast double-tee construction. It is not necessary to describe it as a new, experimental or alternative method. It is another construction method with its own advantages, limitations and appropriate applications.

For a deeper discussion of this category, see The UHPC Panel-and-Beam Construction Method for Parking Structures.

This is not about declaring one method best for every project. It is about choosing the right method for the owner’s site, priorities, operating requirements and long-term asset strategy.

Cast-in-place concrete

Cast-in-place structures are formed and poured at the project site. Reinforcing steel, formwork, shoring, concrete placement, curing and reshoring are major parts of the construction sequence.

Potential advantages include:

• Flexible geometry
• Ability to accommodate irregular footprints
• Familiar structural design practices
• Monolithic construction
• Broad contractor and engineering familiarity
• Suitability for below-grade construction

Potential considerations include:

• Substantial site labour
• Formwork and shoring requirements
• Weather-dependent activities
• Concrete curing and reshoring cycles
• Site-dependent finish and quality control
• Potentially longer superstructure cycles
• Driving-surface protection and crack-control requirements

UHPC panel-and-beam

UHPC panel-and-beam construction uses prefabricated concrete deck panels supported by structural beams. The panels, beams, connections and joints are designed as a coordinated structural assembly.

Potential advantages include:

• Controlled off-site production
• Rapid on-site erection
• Thin, low-permeability deck components
• Reduced structural mass
• Less field formwork and curing
• Potentially lower foundation demand
• Visible and inspectable primary beams
• Ability to coordinate structural behaviour, joints and drainage as a complete system

Potential considerations include:

• Early structural and architectural coordination
• A rational and repetitive structural grid
• Transportation limits
• Delivery and crane access
• Manufacturing and erection tolerances
• Clear interface responsibility among the designer, manufacturer and erector
• Project-specific detailing for unusual geometry or severe exposures

The Kiwi CarPark System is Kiwi Newton’s implementation of UHPC panel-and-beam construction, combining UHPC deck panels, galvanized structural steel and integrated design-build delivery.

Precast double-tee

Precast double-tee structures use large prestressed concrete members produced off site. The members are transported to the site, erected and connected to form the parking deck. A topping, membrane or other driving-surface strategy may be used depending on the project.

Potential advantages include:

• Established North American production capacity
• Rapid structural erection
• Long-span capability
• Reduced site forming
• Factory production of major structural members
• Familiar design and erection practices

Potential considerations include:

• Structural depth and its effect on floor-to-floor height
• Large transportation and crane requirements
• Numerous flange joints
• Connection maintenance
• Topping or membrane requirements
• Local flange and support-region behaviour
• Potential limitations on irregular layouts

Use the same evaluation criteria for every method

Compare the methods using the same questions:

• How deep is the structural floor system?
• How much does the completed structure weigh?
• How does the system affect the foundations?
• What grid and layout restrictions apply?
• How much site labour, forming and curing are required?
• Can components be manufactured while foundations are constructed?
• How many joints are present?
• Where does tension occur in the exposed driving surface?
• How are cracking and chloride exposure controlled?
• How is water drained from the deck?
• Which structural elements are visible and inspectable?
• Which coatings, toppings, membranes or sealants will require replacement?
• How does the method affect the construction schedule?
• Can the structure expand in the future?

6. Identify the Applicable Codes and Standards

A North American parking structure must comply with the requirements adopted by the authority having jurisdiction. The latest published model code is not necessarily the edition legally in force for a specific project.

At the beginning of the project, create a code and standards register that identifies:

• The governing document
• The adopted edition
• Provincial, state or local amendments
• The responsible design discipline
• The reviewing authority
• The applicable project requirement
• Outstanding interpretations or approvals

The following lists are common starting points, not exhaustive project-specific code lists.

Common Canadian codes and standards

• The adopted provincial or territorial building code
• The adopted provincial or territorial fire code
• Municipal zoning and parking bylaws
• The National Building Code of Canada, where adopted or referenced
• CSA S413, Parking Structures
• CSA A23.1/A23.2 for concrete materials, construction and testing
• CSA A23.3 for the design of concrete structures
• CSA A23.4 for precast concrete materials and construction
• CSA S16 where structural steel is used
• Applicable accessibility legislation and standards
• The Canadian Electrical Code
• Applicable plumbing and drainage codes
• Elevator and elevating-device requirements
• Occupational health and construction-safety requirements
• Municipal stormwater and sewer requirements
• Owner-specific or agency-specific criteria

CSA S413 addresses durability requirements for new parking structures and portions of buildings exposed to vehicular traffic. Kiwi provides a practical overview in CSA S413: Ensuring Durability and Compliance in Canadian Parking Structures.

Common United States codes and standards

• The adopted state or local building code, often based on the International Building Code
• The adopted fire code
• Local zoning and parking ordinances
• ASCE/SEI 7 for structural loads and associated criteria
• ACI 318 for structural concrete
• ACI 301 where specified for concrete construction
• NFPA 88A where adopted or referenced
• NFPA 70, the National Electrical Code
• Applicable PCI standards and recommended practices
• The ADA Standards for accessible parking
• ICC A117.1 where adopted
• Mechanical, plumbing and energy codes
• Elevator requirements
• OSHA construction requirements
• Stormwater and environmental regulations
• Federal, airport, hospital, transit or institutional requirements where applicable

Codes establish minimum requirements. Owners may choose enhanced requirements for durability, service life, user comfort, future expansion, vehicle size, lighting, security or maintenance.

7. Investigate the Site and Soil Conditions

The parking structure cannot be designed in isolation from the site beneath and around it.

Complete site due diligence

Review:

• Property boundaries
• Easements
• Setbacks
• Height restrictions
• Lot coverage
• Existing utilities
• Underground services
• Fire-department access
• Stormwater capacity
• Existing and proposed site entrances
• Adjacent roadways and intersections
• Adjacent buildings
• Construction staging space
• Delivery and crane access
• Overhead power lines
• Environmental conditions
• Floodplain restrictions
• Airport or transportation-corridor restrictions

Study traffic outside the building

Vehicle circulation does not begin at the entrance gate. Evaluate:

• Entry and exit queueing
• Gate, payment or security delays
• Left-turn and right-turn movements
• Nearby traffic signals
• Peak arrival and departure patterns
• Event-related traffic
• Conflicts with pedestrians and cyclists
• Emergency and service access
• Snowbanks near entrances and sightlines

An efficient internal layout can still perform poorly if vehicles queue onto the adjacent road.

Complete a project-specific geotechnical investigation

The geotechnical program should establish:

• Allowable soil-bearing capacity
• Total settlement
• Differential-settlement risk
• Depth to competent bearing material
• Groundwater elevation
• Frost depth
• Existing or undocumented fill
• Compressible or organic soils
• Rock elevation
• Liquefaction potential where applicable
• Seismic site classification
• Excavation conditions
• Dewatering requirements
• Potential contamination

Regional geotechnical information can assist with early feasibility, but it should not replace site-specific boreholes and engineering recommendations.

Coordinate the superstructure with the soil

A lighter superstructure generally creates lower gravity reactions and foundation loads. Depending on the site, this may reduce footing size, excavation, concrete and reinforcing. It can also improve the feasibility of construction on lower-bearing-capacity soils.

However, lower structural weight does not automatically eliminate piles or deep foundations. Final foundation design also depends on settlement, groundwater, column spacing, lateral loads and site conditions.

The best parking layout is not necessarily the best overall project if it places heavy, concentrated reactions on poor soil.

8. Start With the Required Parking Dimensions

Parking dimensions are usually governed by municipal zoning, accessibility requirements, owner criteria and the types of vehicles expected.

Confirm:

• Standard stall width
• Standard stall length
• Accessible stall dimensions
• Van-accessible stall dimensions
• Access-aisle dimensions
• Drive-aisle width
• Turning radii
• Ramp width
• Maximum ramp slope
• Maximum parking-floor slope
• Vertical-clearance requirements
• Bicycle and motorcycle requirements

Use metric and imperial units

This article uses metric dimensions first, followed by approximate imperial equivalents in parentheses.

Illustrative parking dimensions might include:

• Stall width: 2.6 to 2.8 m (approximately 8 ft 6 in to 9 ft 2 in)
• Stall length: 5.6 to 6.0 m (approximately 18 ft 4 in to 19 ft 8 in)
• Two-way aisle: 6.0 to 6.5 m (approximately 19 ft 8 in to 21 ft 4 in)
• Clear height: approximately 2.1 m (approximately 6 ft 11 in), subject to the governing requirements and vehicle route

These are examples, not universal requirements. The governing zoning bylaw, accessibility standard, building code and owner criteria must be confirmed for every project.

Define the parking bay

A typical double-loaded parking bay consists of:

Parking stall length + drive aisle + parking stall length

For example:

• Stall length: 5.9 m
• Drive aisle: 6.2 m
• Stall length: 5.9 m
• Total bay width: 18 m (approximately 60 ft)

Depending on local dimensions, a double-loaded bay may be approximately 17.2 to 18.5 m wide (approximately 56 to 61 ft).

The bay width influences:

• The building width
• Structural spans
• Column positions
• Ramp configurations
• Drainage direction
• Lighting
• Façade repetition
• Construction efficiency

9. Design an Efficient Parking Layout

A useful early performance measure is gross floor area per parking space:

Gross floor area ÷ total number of parking spaces

Gross floor area should include:

• Parking stalls
• Drive aisles
• Ramps
• Stairs
• Elevators
• Pedestrian circulation
• Required service rooms

For an efficient above-grade layout, approximately 28 m² (approximately 300 sq. ft.) per stall can be a useful early benchmark. Results above approximately 32.5 m² (approximately 350 sq. ft.) per stall may indicate that ramps, irregular site conditions, circulation or non-parking areas are reducing efficiency.

These are planning benchmarks, not mandatory targets. A hospital structure with generous pedestrian routes, a small one-bay structure with a dedicated ramp or an irregular urban site may reasonably require more area per stall.

The least expensive square footage is the square footage the project does not need to build.

Efficiency should not be achieved by compromising:

• Comfortable stall dimensions
• Turning movements
• Accessible routes
• Pedestrian safety
• Queueing
• Sightlines
• Snow removal
• Required service spaces

Recalculate efficiency throughout design

Calculate area per stall at:

1. Feasibility
2. Concept design
3. Schematic design
4. Design development
5. Preconstruction
6. Final design

If the number begins to rise, identify the reason before the project advances.

10. Select the Ramp and Circulation Arrangement

Parking structures commonly use three circulation arrangements:

1. Dedicated ramps
2. Sloping floors
3. Split-level systems

Dedicated ramps

A dedicated ramp is separate from the main parking floor. It may carry one-way or two-way traffic.

Consider:

• Ramp width
• Maximum slope
• Transition slopes
• Landings
• Queueing
• Turning movements
• Sight distance
• Snow and ice
• The floor area consumed by the ramp
• The parking spaces displaced by the ramp

A one-bay parking structure generally requires a dedicated ramp or another separate vertical-circulation solution. The Carillon Parking Structure is an example of a one-bay layout with a dedicated ramp.

Sloping floors

In a sloping-floor structure, part of the parking floor gradually rises to the next level. Parking can remain on the sloped surface where the permitted slope and accessibility requirements allow.

The building must be long enough to gain the full floor-to-floor height at the permitted slope.

A simplified calculation is:

Required sloping length = floor-to-floor height ÷ permitted slope

For example, a 2.7 m floor-to-floor height at a 5% slope requires approximately 54 m (177 ft) of sloping length before allowing for turning zones, transitions and grid increments.

Sloping-floor arrangements are generally more practical in structures with two or more parking bays. The Joseph Street Parking Structure demonstrates a two-bay sloping-floor layout that avoids a full dedicated internal ramp.

Split-level systems

A split-level arrangement uses shorter elevation changes between adjacent parking bays. Each bay may be approximately half a level above or below the next.

Potential advantages include:

• Efficient use of the drive aisle for vertical movement
• Shorter ramp segments
• Reduced dedicated-ramp area
• Compact vertical circulation

Potential considerations include:

• Wayfinding
• Repeated half-level changes
• Elevator and accessible-route coordination
• Structural and drainage complexity

The Centennial GO Station parking structure is an example of a split-level arrangement.

Compare circulation options using owner-focused criteria

• Gross area per stall
• Required building length
• Driver wayfinding
• Ramp area
• Vehicle speed
• Snow and ice exposure
• Pedestrian conflicts
• Accessibility
• Drainage
• Construction complexity
• Future expansion

11. Establish Clear Heights and Floor-to-Floor Heights

Clear height and floor-to-floor height are related, but they are not the same measurement.

Clear height

Clear height is the unobstructed vertical space available to a vehicle. The lowest item controls the actual clearance, including:

• The underside of the deck or beam
• Lighting
• Pipes
• Signs
• Sprinklers where required
• Security or parking equipment
• Structural deflection

The project should distinguish between:

• Required vehicle clearance
• Actual clear height
• Posted clearance
• Accessible-van route clearance

Consider the expected vehicles

Review:

• Passenger cars
• Pickup trucks
• Sport utility vehicles
• Accessible vans
• Fleet and service vehicles
• Ambulances where applicable
• Vehicles with roof-mounted equipment
• Snow-removal equipment

Floor-to-floor height

Floor-to-floor height includes:

• The required clear height
• The structural depth
• Drainage slopes
• Lighting and services
• Construction tolerances
• Deflection allowances

Reducing unnecessary floor-to-floor height can reduce:

• Overall building height
• Façade area
• Ramp length
• Column length
• Stair travel
• Elevator travel
• Structural material quantities
• Visual mass

However, the height must remain sufficient for every required vehicle route and installed system.

12. Coordinate the Structural Grid, Building Weight and Foundations

Align the structural grid with the parking module

The structural grid should:

• Follow the parking-bay geometry
• Keep columns out of drive aisles where practical
• Minimize interference with stalls
• Coordinate with ramps and level changes
• Support efficient structural spans
• Coordinate with stairs and elevators
• Support the drainage strategy
• Allow repetitive manufacturing and construction
• Accommodate the façade and vehicle barriers
• Support future expansion where required

The grid must also coordinate with foundations, expansion joints, component transportation, erection sequencing and crane access.

Design for all applicable loads

Structural design may need to address:

• Dead load
• Vehicle live load
• Pedestrian live load
• Snow and snow drifting
• Rain and ponding
• Wind
• Seismic effects
• Thermal movement
• Shrinkage and creep
• Vehicle impact
• Barrier loads
• Construction and erection loads
• Snow-removal equipment
• Future expansion loads

Why building weight matters

Building weight affects more than the amount of material in the superstructure.

A lighter structure may create:

• Lower column reactions
• Lower foundation loads
• Smaller foundations, depending on site conditions
• Less excavation
• Less foundation concrete and reinforcing
• Reduced demand on weaker soils
• Lower transportation weight for some components

Weight and seismic design

Seismic forces are inertial forces generated as the mass of a structure accelerates during an earthquake. All else being equal, reducing effective seismic weight generally reduces the inertial forces that the lateral system and foundations must resist.

Actual seismic demand also depends on:

• Regional seismic hazard
• Site classification
• Structural period
• Stiffness
• Ductility
• The selected lateral-force-resisting system
• Building importance
• Structural regularity
• Connection detailing

A lighter building is not automatically a better seismic building. The complete system must still provide code-compliant strength, stiffness, ductility, load paths and connections. However, building mass is an important part of the calculation and should be considered when comparing structural methods.

13. Limit Tension and Cracking in the Concrete Driving Surface

The top of a parking deck is exposed directly to water, snow, road salt, chlorides, freeze-thaw cycles, tire wear and repeated vehicle loading.

Concrete performs very well in compression but is relatively weak in tension. Reinforcing steel can carry tensile forces after the concrete cracks, but cracks in the exposed surface may become pathways for water and chlorides.

Driving-surface design objectives

The structural and durability strategy should seek to:

• Limit tensile demand at the exposed top surface
• Control crack widths
• Reduce unnecessary joints
• Protect reinforcement and connections
• Keep salt-laden water away from vulnerable materials
• Make joints and cracks accessible for inspection
• Coordinate structural behaviour with drainage

Understand where top-surface tension occurs

Continuous structural behaviour can create negative, or hogging, moments over supports. This places the top of the concrete deck in tension near the support.

In cast-in-place systems, the reinforcement and crack-control strategy must account for this behaviour.

In double-tee systems, owners should understand how:

• The flange spans between stems
• Adjacent flanges are connected
• Localized wheel loading is distributed
• Restraint and temperature movement are accommodated
• Any topping or protection system behaves
• Top-surface cracks near stems, connections or supports are controlled

This does not mean that all double-tee structures will experience unacceptable cracking. Properly designed, detailed, constructed and maintained systems can perform well. The important issue is that the exposed driving surface must be evaluated as part of the structural and durability strategy.

Panel-and-beam behaviour

UHPC panel-and-beam systems can be configured so that deck panels behave primarily as simply supported elements between beams. This can reduce the continuous negative-moment condition that would otherwise place the top surface into tension over a support.

Any necessary movement or localized tension can then be managed through designed joints, connections and reinforcement rather than uncontrolled cracking across the driving surface.

The dense, low-permeability properties of UHPC also help slow the movement of water and chlorides through the concrete. This does not eliminate the need for good engineering, joints, drainage or maintenance, but it changes the deck’s exposure and deterioration strategy.

Ask every structural-system provider: Where does tension occur in the exposed driving surface, and how are cracking, joints and chloride exposure controlled?

For further reading, see Steel Beams in Parking Structures: Inspectable Steel vs. Hidden Rebar and Why Parking Structures Collapse.

14. Determine Whether the Structure Can Be Open-Air

Early in design, determine whether the facility will be:

• An above-grade open-air parking structure
• An enclosed parking structure
• An underground structure
• A partially below-grade structure
• Connected to another building
• Part of a mixed-use development
• Supporting another occupancy above

Open-air classification is based on the requirements of the governing building code. It typically depends on factors such as perimeter openings, the distribution of those openings and the distance from interior areas to the exterior.

Why classification matters

It may affect:

• Natural or mechanical ventilation
• Fire-resistance requirements
• Fire-protection systems
• Smoke control
• Façade openings
• Allowable building area and height
• Construction type
• Emergency access
• Operating energy
• Capital and maintenance costs

Requirements for sprinklers, standpipes, alarms, structural fire protection and ventilation vary by jurisdiction, size, height, openness, occupancy and connection to adjacent buildings. They should not be assumed from another project.

For a more detailed explanation, see Open-Air Parking Structures: Everything You Need to Know.

Mixed-use and occupied construction

Adding housing, offices, retail or another occupancy above or beside the parking can materially change:

• Structural loading
• Fire separations
• Building classification
• Mechanical systems
• Vibration and acoustic criteria
• Foundations
• Construction sequencing
• Cost and schedule

These requirements must be established before the parking structure is substantially designed.

15. Design for Water, Salt, Drainage and Winter Conditions

Water and salt are among the most important long-term exposures in a parking structure.

Follow the water

1. Vehicles carry rain, snow, ice and salt into the structure.
2. Wind carries precipitation through open façades.
3. Water moves across the deck.
4. Floor slopes direct it toward drains, scuppers or trench drains.
5. Cracks, joints, penetrations and connections are exposed along the route.
6. The drainage system carries the water away.
7. The entire system must continue to function during freezing conditions.

Coordinate the drainage system with the structure

Address:

• Primary floor slopes
• Secondary slopes
• Point drains
• Trench drains
• Entrance drainage
• Scuppers
• Downpipes
• Drain piping routes
• Expansion joints
• Construction joints
• Panel joints
• Service penetrations
• Freeze protection
• Salt-laden runoff
• Preventing water from dripping onto vehicles below
• Access for inspection and cleaning

Drainage should not be treated only as a plumbing system. It affects the floor elevations, structural slopes, joint locations, ramp configuration and long-term durability.

Ask practical drainage questions

• Can every drain be reached and cleaned?
• What happens if a drain freezes or becomes blocked?
• Where will water pond if the primary drain fails?
• Are joints located above parked vehicles?
• Can water reach concealed reinforcement or connections?
• How will salt-laden runoff be collected and discharged?
• Who is responsible for the interface between the structure and drainage system?

Choose a complete durability strategy

The strategy may include:

• Low-permeability concrete
• Adequate concrete cover
• Crack control
• Traffic-bearing membranes or toppings where required
• Durable joint systems
• Protected reinforcement
• Hot-dip galvanized structural steel
• Stainless or otherwise protected components in severe exposure zones
• Accessible and inspectable details
• A defined washing and maintenance program

For more information about visible corrosion protection, see Galvanized Steel for Parking Structure Construction.

Plan for snow and winter operations

In Canada and northern regions of the United States, address:

• Top-deck snow removal
• Designated snow-storage areas
• Snow-drop zones
• Concentrated snow-pile loads
• Plow routes and turning movements
• Plow impact on barriers and façades
• Ramp icing
• Frozen drains
• De-icing materials
• Snowmelt runoff
• Freeze protection for exposed pipes
• Snow-removal equipment weight
• Temporary closures during severe weather

Operators should know where snow may be stored and where it must not be stockpiled. Concentrating snow in an area that was not designed for the additional load can create an avoidable structural risk.

16. Design for Accessibility, Safety and User Comfort

A parking structure can comply with code and still feel uncomfortable or unsafe. The design should address both actual safety and the user’s perception of safety.

Plan pedestrian routes early

Identify:

• Where people will enter and leave the structure
• The destination buildings and site paths
• Accessible routes
• Protected pedestrian walkways
• Drive-aisle crossings
• Stair and elevator locations
• Travel distances
• Weather protection
• Passenger-loading areas
• Conflicts at vehicle entrances and exits

Stairs and elevators should be positioned where people naturally want to go, not in leftover spaces after the parking layout is complete.

Accessibility

Coordinate:

• The required number and distribution of accessible spaces
• Van-accessible stalls
• Access aisles
• Accessible vertical clearances
• Accessible routes to entrances and elevators
• Surface slopes
• Door and gate operation
• Pay stations and access-control equipment
• Passenger-loading zones
• Signage

Accessibility requirements vary between Canadian jurisdictions and between the ADA, state codes and local requirements in the United States. Confirm the governing criteria before setting the layout and clear heights.

CPTED and perceived safety

Crime Prevention Through Environmental Design, or CPTED, should influence the parking layout and architectural design from the beginning.

Consider:

• Long sightlines
• Natural surveillance
• Open drive aisles
• Minimal visual obstructions
• Visible elevators
• Open or glazed stair towers
• Uniform lighting
• Reduced glare
• Minimal hiding places
• Clearly defined entrances and exits
• Wayfinding
• Camera coverage
• Emergency communication
• Access control where appropriate
• A clean and well-maintained appearance

The long spans and glazed circulation elements at projects such as Centennial GO Station demonstrate how structure and architecture can support visibility and user comfort.

See CPTED for Parking Structures for a deeper discussion.

Vehicle barriers and impact protection

Vehicle barriers, guards and façade protection are structural safety systems, not decorative accessories.

Coordinate:

• Code-specified vehicle impact loads
• Barrier height and geometry
• Connections to the primary structure
• Protection around openings and ramps
• Column protection
• Snowplow impact
• Pedestrian fall protection
• Façade attachment

17. Plan Electrical Systems, EV Charging and Parking Technology

Electrical and parking technology should be planned before the structural design is complete. Adding systems later can require visible conduit, structural penetrations, additional rooms and expensive service upgrades.

EV charging

Establish:

• The opening-day charger count
• The future charger count
• The number of EV-ready spaces
• Electrical-service capacity
• Transformer requirements
• Load management
• Panel and electrical-room locations
• Conduit pathways
• Future rough-ins
• Protection from vehicles, water and salt
• Maintenance and replacement access

The important decision is not only how many chargers to install today. It is whether the service, distribution system and pathways can support future expansion.

Parking and security technology

Consider:

• Lighting and lighting controls
• Emergency power
• Access and revenue control
• Barrier gates
• Security cameras
• Emergency call stations
• Parking-count systems
• Space-availability signs
• License-plate recognition
• Cellular and Wi-Fi coverage
• Digital wayfinding
• Building-management integration

Solar energy and mobility hubs

A parking structure can support more than stored vehicles. It may also serve as:

• An EV charging hub
• A solar photovoltaic platform
• A battery-storage location
• A bicycle and micromobility hub
• A connection point for transit or shuttle services

The Humber College parking structure demonstrates how structured parking, solar power, EV charging, bicycle storage and occupied spaces can be integrated within a campus project.

Develop the architectural form around the function

After the functional geometry is established, architecture should address:

• Relationship to surrounding buildings
• Street frontage
• Pedestrian scale
• Façade openness
• Screening
• Glare and light spill
• Noise
• Signage and branding
• Public art
• Ground-floor activity
• Material durability
• Façade maintenance
• Snowplow and vehicle impact

A parking structure can have an attractive and context-sensitive exterior without compromising its parking function, visibility, ventilation or long-term durability.

Plan for future expansion

Future expansion may be:

• Vertical, by adding more levels
• Horizontal, by adding another bay
• Operational, by adding chargers or parking technology
• Programmatic, by adding solar, bicycle facilities or occupied space

Future expansion affects foundations, columns, lateral systems, stairs, elevators, ramps, drainage, permits and construction access. It must be designed into the initial project rather than assumed later.

18. Plan How the Structure Will Be Built

A technically efficient structure may still be difficult or expensive to construct if logistics are not considered during design.

Cast-in-place construction logistics

Plan:

• Formwork
• Shoring and reshoring
• Reinforcing delivery and storage
• Concrete-truck routes
• Pump locations
• Pour sequencing
• Curing
• Winter protection
• Site labour
• Temporary access
• Form removal and material handling

Prefabricated construction logistics

Plan:

• Component dimensions and weights
• Transportation routes
• Road and bridge restrictions
• Truck turning and unloading
• Delivery sequencing
• On-site storage
• Crane size and reach
• Crane setup locations
• Overhead restrictions
• Temporary bracing
• Erection tolerances
• Weather limits
• Just-in-time delivery
• Stability of the partially completed structure

Airport, campus, healthcare and urban projects may have strict limits on delivery hours, crane heights, road closures, noise and occupied-site access. These restrictions should be part of the structural and erection plan.

The Ronald Reagan Washington National Airport parking project illustrates the importance of integrating foundations, component delivery, crane planning, phasing and active-site operations.

Use concurrent work where appropriate

In an integrated prefabricated design-build process, the project may be able to advance:

• Sitework and foundations
• Structural design
• Shop drawings
• Production planning
• Component manufacturing
• Long-lead procurement
• Construction logistics

in overlapping phases.

The schedule advantage does not result only from using a stronger concrete mix. It results from coordinating design, engineering, production, procurement, delivery and erection as one process.

For more schedule context, see How Long Does It Take to Build a Parking Structure?

Maintain operations during construction

Plan for:

• Temporary parking
• Staff or public shuttles
• Emergency access
• Pedestrian detours
• Construction separation
• Partial openings
• Noise and dust
• Adjacent building access
• Utility continuity
• Traffic control
• Hospital, airport, campus or transit operations

Quantify:

• Existing spaces temporarily lost
• The duration of the loss
• Temporary-parking cost
• Shuttle cost
• Lost revenue
• Operational disruption

Establish quality assurance and interface responsibility

The quality plan should address:

• Design reviews
• Material qualifications
• Concrete testing
• Plant quality control
• Shop-drawing review
• Weld inspection
• Galvanizing inspection
• Connection inspection
• Foundation surveys
• Anchor and embed verification
• Erection tolerances
• Joint mockups
• Drainage testing
• Façade interfaces
• Deficiency tracking
• As-built verification

Clearly assign responsibility for:

• Foundations to columns
• Columns to beams
• Beams to deck panels
• Panels to joints
• Structure to drainage
• Structure to barriers
• Structure to façade
• Structure to stairs and elevators
• Structural openings and building services

Integrated responsibility reduces gaps between separate designers, suppliers and contractors.

19. Evaluate Lifecycle Value, Commissioning and Maintenance

Compare lifecycle value, not only initial price

Evaluate:

• Initial construction cost
• Cost per parking space
• Cost per square metre or square foot
• Construction duration
• Temporary-parking and operational costs
• Membrane or topping replacement
• Joint maintenance
• Drain cleaning
• Concrete and corrosion repairs
• Painting or recoating
• Lighting and ventilation energy
• Elevator maintenance
• Inspection access
• Future rehabilitation
• Operational shutdowns
• Expansion capability
• Residual value

Consider inspectability

Ask:

• Can the primary structural elements be seen?
• Can the joints be reached?
• Can corrosion be detected early?
• Can drains be cleaned easily?
• Can localized repairs be completed without major demolition?
• Are protection systems replaceable?
• Can the owner understand the condition of the structure without widespread destructive investigation?

Use decision gates

Before proceeding to the next stage, confirm that the major decisions still work together.

Feasibility gate

• Parking demand
• Site capacity
• Zoning
• Preliminary geotechnical conditions
• Budget
• Schedule

Construction-method gate

• Three-method comparison
• Structural depth
• Building weight
• Foundation implications
• Construction logistics
• Durability strategy
• Lifecycle requirements

Concept-design gate

• Stall count
• Area per stall
• Bay dimensions
• Ramp arrangement
• Clear heights
• Open-air strategy
• Site access

Design-development gate

• Structural grid
• Drainage
• Joints
• Accessibility
• CPTED
• Electrical capacity
• Façade
• Construction phasing

Construction-release gate

• Permits and approvals
• Foundation information
• Shop drawings
• Long-lead equipment
• Manufacturing release
• Erection plan
• Safety plan
• Quality plan

Commission the completed structure

Before opening, complete:

• Drainage testing
• Lighting verification
• Access-control testing
• Parking-technology testing
• Elevator commissioning
• Fire and life-safety inspections
• Vehicle-barrier inspections
• Accessibility review
• Wayfinding review
• Clearance verification
• Deficiency correction
• Final cleaning

Provide a complete turnover package

The owner should receive:

• As-built drawings
• Operations and maintenance manuals
• Warranties
• Inspection schedules
• Joint-maintenance requirements
• Drain-cleaning procedures
• Snow-removal limitations
• Allowable loading information
• A baseline condition survey
• Training for facilities staff

Maintain the structure as infrastructure

A long service life depends on both good initial design and disciplined maintenance.

Establish a program for:

• Routine washing and chloride removal
• Drain inspections
• Joint inspections
• Concrete inspections
• Steel and coating inspections
• Barrier inspections
• Lighting maintenance
• Annual condition reviews
• Periodic structural assessments
• Repair prioritization
• Maintenance records

Conclusion: Make the Decisions in the Right Order

Building a successful parking structure requires more than selecting a structural system and producing construction drawings.

The process should:

1. Define the parking function.
2. Identify the decisions that control cost and schedule.
3. Organize an integrated design-build process.
4. Compare cast-in-place concrete, UHPC panel-and-beam and precast double-tee construction.
5. Establish the governing codes and owner requirements.
6. Understand the site, traffic and soil.
7. Start with the required parking dimensions.
8. Optimize the parking bay, structural grid and area per stall.
9. Select the correct ramp and circulation arrangement.
10. Coordinate clear height, structural depth and floor-to-floor height.
11. Evaluate building weight, foundations and seismic demands.
12. Limit tension and cracking in the exposed driving surface.
13. Control water, salt, drainage and winter exposure.
14. Design for accessibility, safety and user comfort.
15. Plan construction, quality control, commissioning and maintenance.

A parking structure is too interconnected to design effectively through isolated handoffs. Parking geometry, structural design, foundations, drainage, user experience, manufacturing and construction sequencing should be developed together.

An integrated design-build process allows these relationships to be resolved early, when the greatest opportunities remain to improve cost, schedule, durability and long-term performance.

To review examples of completed facilities, visit Kiwi Newton’s parking structure project portfolio. To discuss the planning, design or construction of a new facility, contact Kiwi Newton.

Frequently Asked Questions About Building a Parking Structure

What are the main steps for building a parking structure?

The main steps are to define the parking demand, confirm the site and applicable requirements, investigate the soil, compare construction methods, design the parking layout and ramps, coordinate the structural grid and foundations, design drainage and durability systems, plan construction, commission the facility and establish a maintenance program.

What are the three main parking structure construction methods?

The three main methods are cast-in-place concrete, UHPC panel-and-beam and precast double-tee construction. Each method should be evaluated for layout, structural depth, building weight, foundations, schedule, joints, durability, maintenance and lifecycle value.

How much area is needed per parking space?

An efficient above-grade layout may be approximately 28 m² (approximately 300 sq. ft.) of gross floor area per parking space. Ramps, irregular sites, accessibility, stairs, elevators and other requirements can increase the result.

How wide is a typical parking bay?

A double-loaded parking bay may be approximately 17.2 to 18.5 m wide (approximately 56 to 61 ft), depending on the required stall lengths and drive-aisle width. The actual dimensions must come from the governing bylaws, accessibility requirements and owner criteria.

Can a one-bay parking structure use a sloping-floor layout?

A one-bay structure will generally require a dedicated ramp or another separate vertical-circulation solution. Sloping-floor and split-level layouts are usually more practical when the structure has two or more parking bays.

How long must a building be for a sloping-floor layout?

The required sloping length depends on the floor-to-floor height and maximum permitted parking slope. As a simplified example, gaining 2.7 m of elevation at a 5% slope requires approximately 54 m (177 ft) of sloping floor, before accounting for turning areas, transitions and structural-grid increments.

What determines the floor-to-floor height?

Floor-to-floor height is determined by the required vehicle clearance, structural depth, drainage slope, lighting, signs, pipes, other services, deflection and construction tolerances.

Why does parking structure weight matter?

Building weight affects column reactions, foundation demand, excavation, material quantities and seismic inertial forces. A lighter structure may reduce foundation requirements, although the final design depends on soil capacity, settlement, groundwater and lateral loads.

Why should tension in the top concrete surface be limited?

The top surface is directly exposed to water and road salt. Tensile stress can contribute to cracking, and cracks can create pathways for chlorides to reach reinforcement and connections. The structural system, reinforcement, joints, materials and drainage should work together to control this exposure.

Why is drainage so important?

Vehicles and weather bring water and chlorides into the structure. Effective slopes, drains, joints and piping reduce ponding and limit the amount of time salt-laden water remains in contact with structural materials.

What is an open-air parking structure?

An open-air parking structure provides code-defined natural ventilation through exterior openings. The applicable requirements depend on the adopted building code, building size, height, openness, occupancy and connections to other buildings.

What is the best project-delivery method for a parking structure?

Design-Build and Progressive Design-Build are well suited to parking structures because they allow the parking layout, structural method, foundations, drainage, cost, manufacturing and construction sequence to be developed together. The correct procurement method still depends on the owner, jurisdiction and project requirements.

How should an owner compare parking structure costs?

Compare both initial and lifecycle costs. Include the structure, foundations, façade, building systems, construction duration, temporary parking, membranes, joints, drainage, inspections, repairs, energy, operational disruption and future rehabilitation.

How often does a parking structure require maintenance?

Every parking structure requires routine cleaning, drainage maintenance and periodic inspection. The exact schedule depends on the construction method, materials, exposure, climate, traffic, protection systems and owner requirements.

Can a parking structure be expanded later?

Yes, some structures can be designed for future vertical or horizontal expansion. The initial foundations, columns, lateral system, ramps, stairs, elevators, drainage and approvals must account for the future work.