A Design Code (DC) is a set of illustrated design rules and requirements instructing and guiding the physical development of an area. DCs in various forms have been widely used in cities all over Europe (Great Britain, Italy, France, Germany and the Netherlands) and China, as a means to focus on the delivery of high quality urban development. DCs are usually in line with national and regional planning guidance and derive out of and are consistent with a development plan to which it should specifically refer (CABE, 2003). DCs offer a wide range of opportunities to contribute to making a city or neighbourhood more socially integrative and inclusive.

The graphic and written components of the code are detailed and precise, and build upon a design vision such as a masterplan or other design framework for a site (Communities and Local Government, 2006). The set of rules, selected through a design operation, intend to steer and control the forces that guide urban transformation, by developing and preserving specific qualities. Thus, design codes differ from each other in terms of design principles (BOX 1), scale, and the freedom they guarantee (Pisano et al., 2020). Requirements, where possible, form part of the legal arrangements on what and how development occurs in the area governed by the code (CABE, 2003).

The code may include minimum building distances, minimum driveway width, maximum floor area ratio, maximum front yard depth, maximum lot coverage, etc., or simple parameters related to land use, such as percentages of the total development area related to built-up areas, open spaces, etc., (BOX 2). Guidelines are often adopted by the planning authority, following public consultation. Thus, design codes are different from land use zoning regulations which usually don’t provide such details  (Communities and Local Government, 2006). Nevertheless, in Germany, design regulations are incorporated in the Binding Land-use Plan (Bebauungsplan), drawn up for a section of the municipal territory. This plan must be developed on the basis of the Preparatory Land-use Plan (Flächennutzungsplan) and sets out the legally binding stipulations for urban structure. The design parameters are defined in the German Land Utilisation Ordinance (Baunutzungsverordnung) (ARL, 2008).

Key Words: Design code; high quality urbanism; urban extension

The set of rules contained in a design code intend to steer and control the forces that guide housing transformation by developing and preserving specific qualities in the urban expansion area like density, heterogeneity, open spaces, material quality and environmental standards. They may contribute to diversity of design and social groups living in a neighbourhood. Thus, they help to bring about social mix and support social integration in cities.

This tool was selected through the analysis of good practices in Europe. It was discussed in international working groups where it was concluded that it is applied mainly in urban renewal projects in Europe and to some extent also in China. However, until now, it is neither in Europe nor in China a common tool of municipal planning of urban expansion areas.

Design codes are crucial for delivering sustainable and inclusive projects as the design of new areas can be planned and regulated to achieve a higher quality outcome. However, DCs are usually of less value for small sites where a single developer is responsible for the whole development (Communities and Local Government, 2006). Extensive evidence underpins their potential to deliver improved design quality, and an efficient and coordinated development process (Communities and Local Government, 2006). Additionally, appropriate design codes can help to increase property values, reduce crime, contribute to public health and ease transport problems (CABE, 2003, Dannenberg et al., 2003, MacDonald, 2015).

Design codes improve flexibility and freedom between the different phases of the design process, help to reduce the number of negotiations and planning inquiries, and allow to propose an inclusive design process able to clarify the specific qualities that have to be delivered (Pisano et al., 2020).

Design codes can as well be destructive if they do not include stakeholders’ participation and principles of place-making. Side effects might include the limitation of designers’ creativity, biased way-of-working towards converging on solutions too rapidly, and inflexibility over the time.

Upton Design Code, Northampton, UK

Upton is one of a large number of urban extensions planned around the fringes of Northampton in England (map). The land was acquired by Northampton Development Corporation and then transferred to English Partnerships (EP) [1]. In 2001, the Upton Working Group was formed, incorporating EP, Northampton Borough Council, the Prince’s Foundation (PF) [2], and a private design team. After a series of Enquiry by Design exercises a number of major design changes were incorporated to the original proposal (Isherwood, 2013).  As a result, the masterplan and accompanying design code set very high standards in terms of environmental quality and housing density, with a mix of market and affordable tenures.

Upton Design Code was inspired in the Northamptonshire vernacular, including the local urban morphology, architecture and landscape design. The use of local materials helped to establish the urban extension as part of Northampton but with its own identity (TCPA, 2007). The architecture reflects Northampton character in building form, materials and general details (Figure 1). Enforced rules cover the layout of the estate to the pitch of the roofs, and even the type of light bulbs used [3]. Additionally, the design code involves a comprehensive set of environmental standards. All dwellings are required to meet the BREEAM/EcoHomes rating of ‘Excellent’, to reduce CO2 emissions to less that 20kg/sqm/year and to reduce water consumption by various means. Installed features include photovoltaic systems, micro combine heat and power, rainwater harvesting, passive solar design (Figure 2), solar water heating,  biomass central heating and green roofs (Isherwood, 2013, The Scottish Centre for Regeneration et al., 2011).

The Upton Design Code was included in the developer procurement brief for each parcel of land to be released. Shortlisted bidders submitted a design and financial offer. In the overall tender assessment, the relative weightings for design: financial offer are 70:30  (Communities and Local Government, 2006). All in all, the design code ensured coordination between the different development sites within Upton and provided a level of certainty to developers of the quality and character of adjacent development (TCPA, 2007).

[1] English Partnerships was the national regeneration agency, supporting high quality sustainable growth in England. It was a non-departmental public body sponsored by the Department for Communities and Local Government. In 2008 was replaced by the Homes and Communities Agency.

[2] The Prince's Foundation is an educational charity established in 1986, to improve the life quality of people by teaching and practicing ecological ways of planning, designing and building.

[3] https://www.theguardian.com/society/2005/sep/21/communities.guardiansocietysupplement (retrieved July 19, 2020)

Design Code Vathorst, Amersfoort, The Netherlands

Vathorst, is the largest of three urban extension areas (including Nieuwland and Kattenbroek) planned in Amersfoort (map). The development forms part of the government’s former VINEX ten year housing programme (1995-2005) designed to increase the national housing stock by over 7%. Before the new areas were constructed, the Dutch government brought together design panels made up by representatives of the local and regional authorities (Cousins, 2009). The municipality of Amersfoort had the vision that new areas should be for everyone, with no separation of the poorer and richer households as had happened previously in VINEX neighbourhoods (URBED, 2008). The local authority determined general urban design criteria and installed the basic infrastructure of roads and utilities. It then sold lots back to private developers and housing associations.

For development purposes a joint development company was set up in 1988 between the council and five different property developers (Development Company Vathorst - OBV). A quality team was appointed to establish the design quality framework to be enforced, like heating from a central incinerator, solar energy and a clean water sewer system. Landscape designers ensured that canals and trees were kept and specified special types of soil, herbs and shrubs for birds (Cousins, 2009).  As a result, master planners, i.e., the urban design firm West 8 and the planning company KuiperCompagnons, and the quality team designed a balance of contemporary and classical (traditional) sustainable urban expansion area.

The masterplan 'A World of Difference' and the detailed design for Vathorst took long time. It was developed during 1996 and2000, and contains 11.000 dwellings, 90 hectares of commercial, industrial and office spaces and its required public facilities. The plan consists of different neighbourhoods, each of one with a distinctive character (URBED, 2008, Cousins, 2009):

• The village of Hooglanderveen is the cultural heart of the area where designers attempted to create a “village” character;
• Werkstad (City of Labour) is characterised by the industrial, commercial and office land use and it is located at the junction of national infrastructure.
• De Velden (The Fields) is located in the original landscape, between the existing wooded banks, ditches and farmsteads that have been preserved. The houses are designed in a classical style with low-density and diverse architecture respecting the existing rural landscape with tree lines.
• De Bron (The Springs) is a large water retention area with long wooded banks and a view to a farmstead. A high-density housing cluster was developed around a water basin (Figure 1).
• De Laak (The Lake), is a high density housing area (65 houses p/ha) designed as a homage to the tradition of old Dutch canal cities, with a waterways system connected to the nearby IJsselmeer lake. Individual canal side houses, embankments and mooring posts are characteristic features of this sector.

Once agreements had been secured, building work started in 2001, with occupation in 2002. Eight different builders and around 50 different architects were involved. The individual development areas were quite small with a maximum of 70 to 80 homes (ranging from 100 to 500 m²) developed by one architect to ensure choice and variety (URBED, 2012). Additionally, within the neighbourhoods there are woonerfs (streets where cyclists and pedestrians have legal priority), and well-designed bridges (Figure 2) cross the channels connecting the roads (Cousins, 2009).

The Vathorst example proved that new housing areas are not necessarily uniform and dull. This has been achieved through bold designed residential quarters having its own distinctive character and providing opportunities for local identity, communication and social integration. 

• Guide on the use of design codes (CABE, 2003): https://www.designcouncil.org.uk/sites/default/files/asset/document/the-use-of-urban-design-codes.pdf
• Urban Design Compendium (English Partnerships and The Housing Corporation, 2007): https://www.diba.cat/c/document_library/get_file?uuid=263508c9-9337-4076-bf53-2f0f2318364c&groupId=7294824
• Manual on Design Codes: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/7623/152675.pdf