ECONOMICS OF BUILDING DESIGN

INTRODUCTION Discuss how changes in the design will affect the construction cost of building.

DESIGN FACTORS

BUILDING PLAN SHAPE Will influence the structure, environment, construction cost and maintanence cost of building . Most economical design is circular shape.WHY???? Because its provides bigger volumewith the minimum enclosing wall. However, it is not a design that is practical and its suitability for building functions is limited.

BUILDING PLAN SHAPE LETS LOOK AT THE EXAMPLE FOR THIS FACTORS AT PAGE 184.

GROUPING OF BUILDING Saving cost from the combined use of party wall. The party wall is shared together by two units of building. LETS LOOK AT THE EXAMPLE FOR THIS FACTORS AT PAGE 186.

BUILDING SIZE An increase in the size of a building will decrease its unit cost. Cost does not rise in proportion with increase in size. The greater floor area is the lower cost per M2 LETS LOOK AT THE EXAMPLE FOR THIS FACTORS AT PAGE 188.

BUILDING STOREY HEIGHT

BUILDING STOREY HEIGHT If the storey height is too low, might cause discomfort such as having to bear with the heat and facing difficulties in providing sufficient clearence. If the building height is too high, total number of the building storey is reduce.

BUILDING STOREY HEIGHT Major cost that will change when the storey height increase: Construction cost for foundation and structural frames Construction cost for stairs, escalator and lift Wall works Ceiling constructions Installation of air-conditioning systems Installation of electrical works Building maintenance

BUILDING TOTAL HEIGHT The construction cost for a high structure is more than low building that provides and offers the same GFA. But the high-rise building is necessary if the land is limited and expensive.

BUILDING TOTAL HEIGHT Several Factors to be considered when designing high-rise building: Bigger GFA/maximum floor use Cost changes according to type, shape and construction of building. The foundation cost/GFA decrease The cost of lift, escalator and stairs increase when height increasa Maintenance cost Space accupied Increase in wiring, piping and air-conditioning system

CHANGES IN NUMBERS OF STOREYS If two building with the same GFA are different in number of storeys, generally the construction cost for the higher building is more expensive. This can be shown in the following examples in page 192.

CIRCULATION AREA GFA and NFA must be close as posible A multi-storey needs litfs, refuse chute etc All these spaces be included in NFA Lets proceed with the example in page 194 for more understanding about this factor.

SITE FACTORS

EFFECTS OF SIZE AND BUILDING SIZE EFFECT OF SITE ON DESIGN BUILDING EFFECT OF SITE ON PLOT RATIO EFFECT ON SITE CONDITION ON DESIGN EFFECTS OF SITE LOCATION ON DESIGN

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