Comparison

 

Comparison of Traditional Construction Methods and  Low-Waste Technologies

 
Process Traditional Methods Low-Waste Technologies

Building Design

Use of materials size does not correspond with the dimensions in the building

With the standard modular approach, walls and slabs are standardized in both size an shape, being interchangeable between different building types
  

Building components not standardized

Standardized building components
   Down-stand beams and columns detrimental to large panel formwork system construction Walls and flat slabs only, no down-stand beams and columns
   Specifications exceed the performance required Modification of specifications to suit the contractor’s available equipment and materials
    Significant unnecessary mid-project variations Less design variation

Formwork

Conventional timber formwork

Large steel panel forms
   Double the cost of using steel panel in long run High initial cost but balanced by the long terms savings in timber formwork
   Labour intensive for erecting and striking formwork Less labour force required for erecting and striking formwork
  

Longer construction duration

High efficiency, twice faster than timber formwork system
   Plastering need for leveling concrete surface Better quality concrete products, concrete surfaces suitable for applying tiles and paints directly
   Reused 8-15 times, several sets of timber forms needed for a high-rise block Reused over 100 times, one set of forms sufficient to complete a block and can be reused in another sites
   Hand lift timber board from floor to floor Tower cranes needed for lifting formwork
   Considerable timber waste produced Waste steel scrapped for recycling, less waste produced

Concrete Work

In-situ placement

Precast concrete
  

Time consuming

Shorter construction time
   Higher labour cost Higher initial cost but relative cheaper for large quantity
   Poor quality, honeycombing often occurs Mass production, high degree of quality control
   Plastering required before applying tiles and paints Elements usually completed with necessary fixtures and finishes, no need for further finishing works
   More waste produced About 30% less waste than in-situ concreting

Masonry Work

Brick walls or concrete block walls

Internal drywall partitions
  

Lower materials cost but higher labour cost

Higher materials cost but lower labour cost
   High skill levels Easy to install, low skill levels
   Thick layer of plaster needed Smooth surface and no plastering needed
   Time consuming Four times faster than masonry work plus plastering
   More waste produced Wet trade not involved, hence less waste generated
   Walls with higher strength Walls with lower strength

Plastering

Conventional mortar cement

Spray Plaster
  

Manual Applying

Mechanical spraying
   Suitable for rough wall surface, further leveling is required Suitable for smooth wall surface, further leveling is not required
   Time consuming Faster construction
   Labour intensive Less labour demand
   More waste generated Less waste generated

Hoarding

Timber hoarding

Steel hoarding
  

Cheaper materials cost, easy to erect

Expensive and demand higher labour force for erection, but safe for passer-by
   Less durable, about 2 years lifetime More durable, about 4.5 years lifetime
   Low reusability, discarded after used once High reusability, waste steel scrapped for recycling
    More timber waste produced 70% less waste

Scaffolding

Conventional bamboo scaffold

Gondola with Passenger Lift
  

Lower initial cost

Higher initial cost, but balanced by saving in materials cost in the long run
   High labour cost Less labour force required
   Less safe for workers More safe for workers
   More bamboo waste produced 80% less waste
 
Cost Comparison of Traditional Methods and  Low-Waste Technologies
 
Traditional Methods

Cost Unit (%)

 Low-Waste Technologies

Cost Unit (%)

Timber formwork
115-125
Large panel steel formwork
100
Timber formwork 100 Aluminum slab formwork 115-125
Timber formwork 100 Semi precast slab 85-95
In-situ facade 115-125 Precast facade 100
In-situ staircase 110-120 Precast concrete staircase 100
Traditional blockworks and plaster 100 Drywall partition 170-190
Traditional plaster 100 Spray plaster 110-120
Traditional Flooring 100 Self-Levelling Flooring 140
In-situ cooking bench 110-120 Precast cooking bench 100
   

Low-Waste Buildings Technologies & Practices
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