As with higher density layouts, the aim here is the creation of a pedestrian-scaled environment by use of enclosing space and structuring chains of spaces. The difference is that the space is enclosed by trees, hedges and shrubs rather than buildings, which become free-standing rather than space-enclosing elements and are contained within the landscape. This is the legitimate context for the detached house.

From the outset of any new development, an appropriate balance must be struck between the design principles of the Arcadia and Boulevard layouts set out below. This balance must address the needs of all users – including people of any age and varying physical and mental abilities.

One way to do this is to incorporate into a development some flexibility to adapt or ‘customise’ parts of dwellings to make them more identifiable – for example, the colour of front doors or rendering, or specific types of planting. This may help to orientate and reassure the partially sighted and people with dementia.

Arcadia, densities up to 8 houses per hectare (3 houses per acre)

In layout terms, Arcadia is the creation of the illusion of a rural environment. It draws on the ‘picturesque’ approach to landscape design typified by the layout of the parks of British country houses in the eighteenth century.

The guiding principle was the use of meandering walks which revealed successive surprise features hidden in a dominant landscape. In the same way, early ‘leafy’ suburbs of the nineteenth and early twentieth century conceal houses among mature trees so that the visitor is more aware of the landscape setting than of the houses themselves.

Today’s Arcadia should strive for the same effect, with a layout devised to allow houses to appear at intervals among trees as surprise features in the landscape. This effect cannot be achieved at densities over 8 houses per hectare (3 houses per acre). Land economics may well dictate that housing at this density is at present the exception rather than the rule in new residential areas. If a Planning Authority wishes to see a wider use made of development laid out according to Arcadian principles, it would do well to consider a special notation for such sites in its Development Plan documents, so as to predetermine an appropriate land value.

As Arcadian layouts are dependent for their effect on a dominant landscape, the most suitable sites will be those which already have a significant density of mature trees and hedges. Consideration must also be given to how the existing tree cover can be enhanced by new planting or where, if existing vegetation is sparse, a new pattern of substantial tree and hedge cover can rapidly be established. The need for rapid establishment should not, however, influence a choice of plant material that is alien to naturally occurring species in Essex. Front gardens should be enclosed by hedges in order for the landscape to dominate the houses. Some design features – including open-plan front lawns that reveal cars parked on drives, built enclosures (such as walls with railings) and substantial gates – are not appropriate to the Arcadia layout.

Boulevard planning at densities up to 13 houses per hectare (5 houses per acre)

Boulevard planning employs a key principle of rural spatial organisation: the landscape dominates the buildings. However, it also employs a key principle of urban design, the enclosure of space –albeit using trees rather than buildings.

There are two possible variations:

• Large trees grow on the front boundary of gardens (this would have to be a requirement of the planning consent, with the established trees protected by Tree Preservation Orders). Houses appear at intervals seen through drive entrances, but no more than one or two are apparent from any viewpoint. Trees always provide the link between one house and the next, with more planting at the rear to unify the composition and contain the space between the houses. Care must be taken to ensure that there is sufficient space for trees to establish and mature. The road is a shared visual space for motorists and pedestrians.

• Avenues of trees line the roads and contain the space for the motorist. At intervals, islands of trees appear to terminate vistas. Buildings are scarcely noticeable. The pedestrian is contained within an inner space formed by the roadside trees and front garden plantings. Such layouts work particularly well when the streets form straight avenues or meander in a gentle, serpentine manner.

Boulevard planning at densities up to 20 houses per hectare (8 houses per acre)

A further variation is possible in a layout that employs a subtle combination of landscape and buildings. Part of the composition relies on creating and enclosing spaces by trees and hedges; part relies on enclosing space with groups of buildings. The appropriate relationship must be created between the height of both buildings and trees and the width of the spaces between them, following the principles elsewhere in this guide.

While the use of detached houses is possible in this context, achieving a positive effect will depend on the use of a common architectural style and detailing for all the houses; on locating garages to the rear of residences; and on using gateways, arches, railings and similar to link houses into a single composition.

Similarly, the houses must be positioned in a strict geometric pattern. It is this geometry of crescent, circus, oval or rectangle that will provide the necessary order. The success of such layouts also depends on abundant and appropriate tree-planting. Sparing use should be made of this layout, with developments of over 20 houses per hectare (8 houses per acre) predominating. This layout is not appropriate for use in smaller sites.