Single core accessed residential building

5.7.1. Single core residential building types

Core homes are usually served by one staircase, or they are divided into sections with each served by its own staircase.

Free-standing dwellings served by a common staircase are also known as core buildings.

(In some situations, "core buildings” are referred to in critical literature as "housing blocks" or "housing towers". These definitions refer to a building’s height. For lack of better terms, a core building is a multi-story building that is usually not too high where the planned width and depth are similar.) On sites that are not very wide, buildings developed in rows are often served by a single stairwell.

Row houses can be developed in sections. Each section might be planned in linear rows or staggered.

A certain degree of plasticity might even be applied to each section’s design, allowing for external modeling of the building’s volume. This form of building is ideal for urban infill sites and corner buildings. Where a site is relatively wide, then a building might be divided into sections for greater efficiency. (fig. 5.29)

Figure 5.26. Basic types of stair core systems in multi-unit housing

5.7.2. Urban development types

Classification demonstrates how a single, infill building can be used to complete a row of buildings.

Single apartments accessed via a common core at each level are rare due to density and cost. This technique may be appropriate in smaller infill projects. (fig. 5.30a)

Figure 5.27. Modular and corner unit housing blocks (examples)

Two apartments accessed from a single core is a system used for larger apartments. This allows for positive passive ventilation "cross drafts" on hot summer days. The two apartments can be identical (mirror image), or they may differ from each other according to site restrictions or floor plan.

Figure 5.30b shows examples of linear plan types, as well as staggered and corner-site schemes.

Three apartments accessed from a single core give rise to more favorable plan types. The most common provides for two large apartments and one small on each floor (rarely two small and one large). Placed on corner sites, this arrangement affords the chance to build three large apartments. (fig. 5.30c) Four apartments accessed from a single core usually occur where a higher proportion of homes are to be provided. These are often, for reasons of economy, accessed by corridors and best used when developing infill sites. Similar to situation with three apartments per floor, this arrangement leads to the development of different sized homes, possibly two larger apartments and two studio flats. For larger apartments, corner sites work better. (fig. 5.30d)

Refer to previous sections of this chapter for 5- to 6-apartment layouts. (fig. 5.27)

Site orientation can also affect the location of the building’s core. Current regulations state a minimum of one habitable room should have direct exposure to the sun. This means northern-exposed apartments cannot be developed. This does not pose problems for two or three apartment arrangements so long as the east and west elevations (along the north-south axis) are exposed. When the axis is east-west, ensure that each apartment has an exposed southern elevation.

When buildings have four or more apartments per floor, ensure that rooms along the north-south axis have elevations exposed to daylight.

In addition to satisfying minimal requirements to ensure that more than room has direct daylight, the living room and the majority of bedrooms should face east or south. Figure 5.31 provides some theoretical schemes for orienting rooms to gain optimal daytime lighting in building plan types with two or three apartments per floor.

Figure 5.28. Examples of core housing unit orientation

Free-standing buildings should be divided in such a way as to provide three free elevations for optimal use. The layout might be similar or variations on a theme.

(Note: Orientation is just one factor to consider when developing ideas. Existing infill sites may have many variations. A well-placed elevation might face a noisy or polluted street, while a poorly-placed

elevation might face a beautifully landscaped park or garden. Balancing these issues must also be taken into consideration).

5.7.3. Free-standing types

Free-standing core houses have four free elevations, making them more favorable than core houses built n rows.

This building type is dedicated to "urban villas" (condominiums) where it is not possible to build single apartments on each floor due to site restrictions. This type of arrangement also applies to luxury residential high-rise towers where large apartments might occupy an entire floor.

Often two apartments are provided on each floor, but usually on smaller sites or where the build ratio is limited. This is usually employed when the design schedule calls for larger apartments.

Three or more apartments per floor are more common types, as shown in examples given in figure 5.32 (based upon existing building schematics).

Figure 5.29. Schematic examples of core house arrangements

5.7.4. Spatial arrangement within individual units

Shown here are examples of individual unit plans within core buildings. In reality, the options are far greater. Consider factors generated by site conditions and the development program. The design program usually indicates the required sizes (e.g, square meters and number of rooms) and the amount of apartments in the building. The architect is responsible for spatial organization.

Rooms that require direct sunlight (the kitchen, for example) must be placed with at least one wall along the external elevation. Rooms that do not require daylight (e.g., bathroom, toilet, corridors and storage space) should be placed elsewhere. Therefore, it is crucial to consider the relationship between the floor plan arrangement and elevations.

Figure 5.33 suggests different floor plan arrangements at the sketch level. These refer to standard and not luxury housing categories.

Figure 5.30. Individual examples of apartments within core house developments

(The measurements given in half-meter increments are for guideline purposes only. These should not be used as working examples).

In most developments, an apartment will have one elevation that receives natural sunlight. This means that rooms should be placed in a linear arrangement, which is best suited to apartments with a small amount of rooms (living room and one bedroom). Kitchens may be placed internally.

If an apartment has two or more bedrooms, a linear plan is not desirable, since it tends to give rise to long access corridors and uncomfortable spatial arrangements.

It is more characteristic for apartments in this building type to have rooms placed on opposing or different elevations. With smaller homes of one living room and one bedroom, this does not really work due to depth of building. However, with larger homes (of one living room and two or more bedrooms), this works well.

Two elevations that meet on the corner of a building often occur within one apartment. These are ideal for the design of small and larger apartments, even more so when two bedrooms or multiple homes are required.

5.7.5. Arrangement of ground floor areas

The ground floor of all core buildings has a plan that is a modification of all upper level plans with consideration for the building's main entrance, common circulation areas, as well as storage and refuse disposal areas.

Figure 5.34 shows examples for buildings with no lift.

A comfortable, architecturally pleasing entrance hall can be created when the stairwell faces the entrance door. (fig. 5.34a, 5.34b and 5.34c)

In these situations, the intermediate landings on the stairwell need to have a minimum headroom clearance of 2.20 m; however efficient this use of space though, in buildings that have a ground floor level around 1.00 m above street level, it can be uncomfortable. Try to avoid this option. (fig. 5.34d) It is always better to enter a building through a spacious, impressive space.

When developed in rows, core houses can have the stairwell and entrance placed in such a way so that a second door can provide access to the garden. This might open directly from the staircase or at the landing level. (fig. 5.34c)

Figure 5.31. Examples of development of staircase at ground floor level

Note

The entry level of the building needs to take into consideration lifestyle questions of comfort: pushchairs, shopping trolleys, the elderly, delivery of luggage, etc. In order to improve the building’s comfort, try to ensure that the difference between the outdoor street level and the indoor floor level is no more than 2 cm.

When a lift is to be included in the design, for reasons of barrier-free access, make sure that there is no difference in floor levels at the entrance level. If care is not taken, it will reduce the development’s market value.

In principle, a building’s market value will be enhanced if barrier-free access is provided to all common areas, lifts, storage rooms, bicycle and pushchair storage areas, postal boxes and garden doors. (AP)

Figure 5.35 shows different schematic arrangements for developing the ground floor. (Specific design schedules will vary, as will site requirements.)

Figure 5.32. Examples of core house developments at ground floor level

Note

Apartments built on the ground floor usually differ from those on upper levels. They may be smaller or less in number. (Consider load-bearing walls, pillars and service ducts – all of which must not be ignored!)

In most multi-story, multi-unit housing developments, it is highly recommended to devote the ground floor to barrier-free apartments. Upper-level homes can easily adapt to changes in level, internal arrangements and general flexibility. Both situations are rational in terms of construction costs and marketable value. (AP)

Free-standing buildings offer more freedom in terms of entrance placement. However, try to avoid placing the main entrance on the rear elevation.