needs to be kept high, to avoid a conflict of brightness. Alternatively the
architect may wish to break up the elevation of his building, by the
introduction of structural elements which articulate the perimeter of the
fac ̧ade. In such cases the wide horizontal windows located between the
vertical structures might be treated in the same manner as the splays of
the more traditional building. The window elevations of buildings need
to be carefully considered when related to the orientation of the fac ̧ades,
with care taken to provide solutions to any exposure where there is a
need for solar shading and protection from glare.
Windows can provide a degree of symbolism; this was apparent on the
type of window used for Anglican churches, which from frequent use
become symbolic of this type of church. Many examples exist of
symbolism in the windows of churches, not least in the stained glass
infilling. A modern example of symbolism in a new extension to an
Anglican church in Boxmoor, where it is clear that the Christian cross is
visible; this may be compared with the original windows.
SOLAR SHADING
This is a subject where expert advice should be sought. There are many
different forms of solar shading; each has its own characteristics,
advantages and disadvantages, and the architect must be sure of the
criteria that should be taken into account when determining the nature of
the shading required and whether some form of adjustability is desirable.
The BRE pamphlet ‘Solar Shading of Buildings’ states that the principal
reasons for needing shading are as follows:
- To reduce the effect of heat gain from the sun
- To cut down sun glare experienced through the windows
- The provision of privacy. This will not normally be a requirement,
but it may be important in certain circumstances. - Reduction of heat gain from the sun
At some times of the year this may be of the greatest importance, but its
need will not be permanent; for certain times of the year the heat gain
may be welcome.
The problem is most acute on South facing exposures, but there may be
special conditions in the building such as abnormally high internal heat
gains, or where the building has to be kept at a low temperature.
Since once the heat gain is within the building envelope, it is difficult to
control, the shading system which stops the heat from getting in in the
first place... the external system... will be better. When contemplating
external shading, it is important to bear in mind the question of structural
stability and the need for periodic cleaning.
- Reduction of sun glare
Glare may result from a direct view of the sun, by reflection from some
outside source such as the building opposite a North facing exposure, or
by reflection from items inside the building; most noticeably from items
which are the object of attention, such as a business machine or
computer. Glare, unlike heat, can be controlled easily from within the
building.
30 Daylighting: Natural Light in Architecture