BS 8579-2020 Guide to the design of balconies and terraces.
4 General principles
4.1 General Balconies, terraces and access decks should be designed to provide amenity for the building users and should be sized appropriately for the intended use. Balconies form a significant feature on the facade of many buildings, very often forming part of the character of the building. High-quality design is therefore important to maintain the quality of cities and building stock. Design can be separated into two aspects: aesthetic and functional. NOTE This British Standard does not cover the former as the drivers are numerous and guidance can be found in other documents. Good functionality is vital to the long-term and safe enjoyment of a balcony. The design should aim to leave a legacy of quality and functionality, without nuisance to building occupants or the public, with adequate provision for maintenance.
4.2 Relationship of balconies to the building A balcony can be one of several types, or even a combination. A balcony can project beyond the walls of a building; it can be formed within a recess of a building; or it can be a hybrid of both. It can be formed upon a single wall or at a corner between walls on different planes.
5 Enclosure of balconies and small terraces
5.1 General A balcony or small terrace can be open, wholly or partly covered by another balcony or roof above, or it can be enclosed by a weather screen onone or more sides and a roof or balcony above, thus creating an enclosed balcony. Figure 2 illustrates the typical features of an enclosed balcony. Mechanical ventilation should be ducted past the balcony from the interior to outside of the weather screen.
Factors to be considered in the design include:
a) safety where the enclosure is acting as a guarding;
b] the effects of wind on any opening components;
c) the potential for water penetrating the balcony with and without the screen open;
d) the effects of enclosure on fire and smoke transmission (see Clause 12 for performance in fire);
e]) the effects of enclosure on acoustics into and between apartments (see Clause 17); and
f) cleaning and maintenance.
5.2 Daylight, thermal, ventilation and acoustic considerations
In a temperate climate such as the UK, balconies in proximity to windows have environmental effects upon the interior of the building. These include:
a) providing beneficial shading on certain facade orientations from detrimental high and medium angle sunlight in summer, thus offering an aid to passive cooling of the interior spaces;
b) providing too much shading on certain facade orientations that would benefit from low angle solar gain in winter;
c) providing too much shading from beneficial daylight to the interior spaces; and
d) providing beneficial acoustic buffering to the internal spaces (see Clause 17).
Enclosure of balconies can result in the fllowing additional environmental efects upon the interior
of the building:
1) detrimental overheating in the internal occupied space connected to an enclosed balcony on certain facade orientations due to the restriction of ventilation to the adjacent interior space and entrapment of incident heat;
2) beneficial passive insulation of adjacent interior space by the thermal buffering effect of the enclosed balcony space in cold weather; and
3) detrimental condensation forming on the inside of a single glazed outer weather screen.BS 8579 pdf download.