An example of split level car park design

How To design a Car Park

In this knowledge article we’ll explain, step-by-step, how to design a raised deck car park and multi-storey car park. We’ll look at different car park layouts, explain standard UK car park bay sizes including the size of disabled parking bays, and look at the key aspects of good car park design.  We’ll also explore the advantages of constructing car parks using steel frame, composite car park deck and reinforced concrete floor slabs. 

By the end of September last year (2020) there were 38.8 million licensed vehicles on Great Britain’s roads. of these, 31.9 million were private cars and 1.35 million were motorcycles1.  In these vehicles, we collectively take 25 billion trips by car each year. Each trip starts and ends at a parking space2.

The impact of the pandemic on the future of the ‘daily commute’ remains unknown. Experts suggest consumers doubt the safety of public transport and that the continued requirement for social distancing could force Councils to permanently remove on-street parking. 

A recent attitude survey by the British Parking Association (BPA) also revealed that the lack of available car parking spaces is the key reason for people feeling dissatisfied with parking provision in their local area3.  For a third of people questioned, it can take them over 10 minutes to find a parking space on their local high street.

All this could lead to a potential boom for owners of private single storey and multi-storey-car-parks that are well designed, safe, efficient, equipped with the latest car park technology and located where motorists most need them.

However, you can’t just throw a car park up anywhere you fancy. Building a car park requires careful design and planning with consideration given to multiple factors, ranging from efficient circulation and car park structure to pedestrian and motorist health and safety and crime prevention.  

In the first of two features, we guide you through some of the basic steps you need to take in order to design a raised deck or multi-storey car park in the UK.

car park design using a one way flow

How to Design a Car Park

There is no ‘one size fits all’ solution to designing a raised deck or multi-storey car park. The size and style of a car park will depend greatly on the chief reasons for building it, i.e. what it will be used for, who will use it and when, whether it’s being built to generate an income or to accommodate a workforce, the number of car parking spaces that need to be provided, the location and the land available.

Technical and feasibility studies should be conducted before commencing a car park design to demonstrate whether a car park is viable in this location. They will also study vehicle flow rates and inform the size and type of car park that can be accommodated in the space and location.

What style of Car Park should I build?

Surface level car parks are, by their very nature, simpler to design and cheaper to build as there is no car parking structure to consider. However, their capacity is limited by the size of the land available for car park construction.

Other types of car park include multi-storey-car-parks (sometimes called multi-level-car-parks), underground or basement car parks, single deck car parks (also known as raised deck car parks) and also temporary car parks, where a single storey demountable car parking deck is erected over a surface level car park for a defined period.

With the number of cars in use increasing and available land for car park construction at a premium, the most popular type of car park is the multi-storey or single deck style.

What are the attributes of Good Car Park Design?

A car park is often the first building visitors to a town, city or business come into contact with.  Therefore, all clients are encouraged to build a car park to follow the principles of good car park design.

These attributes include:

  • Easy entry and egress to the car park and the parking bays
  • Uncomplicated and logical traffic flow around the car park
  • Unimpeded movement
  • Light, airy and aesthetically designed
  • Low maintenance and a good life span
  • Safe and secure4*

Before you can design a car park however, you should have an idea of how it is going to be built.

What’s the best method of construction for a Multi-Storey Car Park?

Utilising structural steel frames and composite steel decking for car park construction is proving to be a popular approach.  Building multi-storey-car-parks using steel allows all of the key attributes of good car park design to be met and offers greater design flexibility. The car park structure can be designed to maximise the number of spaces delivered, rather than the number of spaces being determined by the shape of the car park structure, as is the case with car parks constructed from concrete. Steel frame also accommodates different car park cladding styles, enables the easy integration of modern car park technologies and is vandal proof, robust and fire resistant.

If that isn’t enough, there is a strong commercial case for building your multi-storey car park in steel frame and composite flooring. Steel is lightweight yet strong, therefore reducing the foundation requirements which results in greatly reduced construction time scales. This is particularly important when the venue requiring the car park needs to remain functional, such as a railway, hospital or retail park.  Reduced timescales can also reap the benefits of reduced build costs.

Steel deck profiles (often referred to as composite metal decking) are manufactured from galvanised steel and can be specified in long spans reducing the number of columns required and increasing the volume of spaces and, as a result, the potential car park revenue. 

An example of a metal deck is Kingspan Multideck 80, which is a steel floor deck manufactured specifically for car park construction that offers unpropped spans of up to 5.4 metres. The deck can be manufactured in magnelis steel for enhanced corrosion protection or the soffit can be colour coated improving interior aesthetics and assisting motorists with car park level indication.

We’ll talk more about constructing a car park in our next post, How to Build a Car Park.

How do you design a car park layout?

The desired flow of vehicles around a multi-storey car park is a major consideration when designing a car park layout, as is the required size and gradient of the ramps connecting the levels together.

Modern car park design adopts two possible flow patterns: one way and two-way flow. These are combined with either 90 degree or angled parking.

  • One-way flow systems combined with angled parking is the ideal, ensuring easy entry and exit to and from parking spaces and the car park building.
  • Two-way flow systems are common in the UK as they allow a higher flow rate.  The trade-off is that they require more space and are therefore less structurally efficient than one-way systems. The reduction in the volume of spaces could also impact on the profitability of the car park, unless they are located in busy urban areas where minimum parking durations could be imposed to increase volume.  Ninety-degree parking is recommended for use with two-way flow systems as angled parking can cause manoeuvring problems for motorists. 
  • Ramps connect the levels in a multi-storey-car-park together. In the UK, the width of ramps should usually be no less than 3.5 metres for a single ramp and 7 metres for a double ramp.   Depending on whether a car park adopts a one way or two-way flow pattern, the width of the ramp should equate to either two parking bay widths or three parking bay widths, respectively.

The slope of the car park ramp should allow clear headroom of at least 2.1 metres with typical slopes ranges from 1:6 up to 1:10.  

What is the best layout for the design of a Multi-Storey-Car-Park?

When designing the layout, the most important factors to consider are simplicity and safety.

You should allow motorists to enter, navigate and exit the car park with ease and to circulate right so they turn on the driver’s side. Ideally you also want to ensure that the driver is presented with as many potential spaces as possible after entering, yet leaves the building quickly and passes as few spaces as possible. 

These design principles benefit the driver and are more likely to encourage frequent use whilst, importantly, reducing the risk of accidents.

Your multi-storey-car-park will most likely adopt one of three common layouts:

  • Split Level: this is probably the most popular car park layout in the UK and when built in steel with column free spans allows row capacities in excess of 24 standard bays and achieves both economic and operational efficiency. It can be used with one-way or two-way circulation patterns and different ramp designs. The layout is simple and includes a separate entrance and exit.

  • Flat Deck: this layout is growing in popularity as it’s simple to construct and easy for motorists to use. This layout is often adopted when the car park levels need to match a neighbouring building, such as a shopping centre, airport or commercial office building.

  • Parking Ramps: this layout allows the motorist the advantage of passing all potential parking bays on entering the car park, but, unless an external express exit is provided, also requires the motorist to pass all of the bays in order to leave the car park which may discourage frequency of use.

How big is a car parking space in the UK?

When designing the layout of your multi-storey-car-park, it’s important to know the minimum sizes for an off-street car parking space in the UK, according to vehicle type.

These are:

  • Standard cars – 2.4 metres wide by 4.8 metres long
  • Light vans – 2.5 metres wide by 5.5 metres long
  • Lorries and large vans – 3.5 metres wide by 18.5 metres long
  • Coaches – 3.5 metres wide by 14 metres long

How big should a disabled car parking space be?

Off street car park spaces for blue badge holders should comply to British Standard 8300:2009 and be 3.6 metres in width, with the difference over a standard bay (1.2 metres) hatched in yellow to allow sufficient access for wheelchair users.

These sizes are based on Government recommendations however local authorities have the power to set their own regulations, for example, Suffolk County Council5 stipulates that a standard car parking bay should be 2.5 metres by 5 metres to allow space for pedestrians to access the car and boot, whilst a blue badge bay should be 3.6 metres by 6.5 metres, incorporating a yellow hatched area of 1 metre.

How many disabled car parking spaces are required in a car park?

When designing your car park layout out, its critical to ensure enough parking spaces are allocated to motorists with disabilities.

Government guidelines recommend that 6% of spaces are set aside for holders of blue badges, unless otherwise advised by local planning restrictions.

However, research undertaken by the British Parking Association in partnership with the DfT found that this ‘rule of thumb’ guidance leads to undersupply in some areas of the UK, and oversupply in others6.

Together with Disabled Motoring UK, they published their own recommendations and car parks that comply are able to apply for Disabled Parking Accreditation 

These recommendations are:

  • 1 – 50 spaces (2 disabled bays plus 3% of total car park)
  • 51 – 200 spaces (3 disabled bays plus 3% of total car park)
  • 201 – 500 spaces (4 disabled bays plus 3% of total car park)
  • 501 – 1000 spaces (5 disabled bays plus 3% of total car park)
  • 1001+ spaces (6 disabled bays plus 3% of total car park)

Understanding the required sizes of UK car parking bays allows you to produce an efficient raised deck or multi-storey car park layout.  However, before the final number of car parking bays in your multi-storey-car-park can be determined, consideration must be given to the width of the ramps allowing cars to travel between car park levels. This, ultimately, will dictate the car park layout and the maximum number of storeys feasible.

Do you need planning permission to build a car park?

Before building a new multi-storey-car-park, or any car park in fact, you will need to obtain planning permission from the local council.

When applying for planning, you’ll need to submit detailed drawings showing the proposed design of your car park and documents that support your application, such as a design and access statement, transport impact assessments, wildlife impact assessments and air pollution reports. It’s worth investing in specialist planning support when making your applications as mistakes can be costly and could lead to your application being refused.

Your drawings should be accompanied by a planning statement that explains how your proposition meets all of the relevant planning policies and explains how it will benefit local users.

You’ll need to demonstrate that your car park:

  • will not contribute to an increase in traffic congestion
  • will not harm the local environment
  • meets an identified parking requirement in the local area
  • will be used for approved types of parking and parking durations
  • suits the context of the site and the adjacent land uses
  • will not impact on the operations or be detrimental to neighbouring businesses, including during construction

Once planning is in place you can start on the build! 

About Metpark UK Raise Deck and Multi-Storey Car Park Designers

Metpark UK benefits from an in-house team of expert raised deck and multi-storey car park designers. If you’d like expert assistance with your car park design, planning application and feasibility studies then Metpark UK can assist. We can also build it for you. For a no obligation and confidential chat about a potential project please contact us.

* The Safer Parking Scheme is a national standard for UK car parks that have low crime and measures in place to ensure the safety of people and vehicles. Car parks meeting its criteria are awarded a ‘Park Mark’ and can display association signage instilling consumer confidenc