Form follows function Although the square building is the simplest plan in shape, one must remember that the shape of a building is dictated by:
Function: i.e. Factory shapes depend on the form of machines used and the production layout. Schools and hospitals rely on natural lighting and therefore tend to be rectangular in shape. Hotels are orientated towards the best view. Site: The slope and shape of a site might dictate the shape of the building especially where the plan to plot ratio approaches one. Economics: Office buildings with depths up to 18m lease more readily to smaller businesses as areas can be easily split to accommodate different concerns. Buildings often become a function of the owners financial success and tend to reflect this in the use of materials and design detail. Size of the building Increases in the size of a house usually produces reductions in unit cost such as the square meter rate. The prime reason for this is that on costs do not rise proportionally with increases in the plan size of a house. Expressed in another way we can say that the Preliminary and General items (these comprise the builder’s management on site, insurances, transport, etc.) expressed as a percentage of total cost tends to decline with an increase in size and cost. A practical illustration would be the construction of two houses for R500,000.00 and R1,500,000.00 respectively:
House A Cost : R500,000.00 Foreman’s salary : R10,000.00/month Construction time : 3 months Percentage of on-costs = R10,000 x 3 ÷ (R500,000 – (R10,000 x 3)) =R 30,000.00 ÷ 470,000 =6.4%
House B Cost : R1,500,000.00 Foreman’s salary : R 10,000.00/month Construction time : 5 months Percentage of on costs = R10,000 x 5 ÷ (R1,500,000 - (R10,000 x5)) =3.4%
In larger houses other reductions in unit costs may arise due to savings in:
Prices paid for materials by the builder Vertical transportation costs in high rise buildings Larger room sizes etc.