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DAHLSENS BUILDING CENTRES
Waste Minimization in a house building project
Andy Sheo Thanh Nguyen
Shafiul Haque
Executive Summary The following report investigates the wastage in a building project focusing on the residential home
construction process; this wastage refers to both material and time. In order to minimise the
wastage, management techniques for time and materials must be utilised. For time management, it
is found that the main cause of delay in time is weather which can’t be controlled. The next
significant cause of delay is “downtime” when construction is in idle, whereby the bulk of this time
on site is found to be caused by delivery issues.
To minimise this issue, the ordering process of materials must be improved in which an ordering
template can be implemented which allows the sales representatives and builders to have improved
communication as the sales rep is kept up to date with the construction process and is able to
remind the builders what needs to be ordered.
The factors causing material waste on site consists of ordering mistakes and difficulty in adapting to
design changes from home buyers. It is found that miscommunication often occurs, causing over
ordering or incorrect materials being ordered resulting in material wastage. In regards to design
changes, it is found that this often causes mistakes in measuring and cutting of materials leading to
extra unused materials on site. To better account for design variations, a sample spreadsheet was
developed to better analyse the material wastage and financial wastage that can come about due to
limitation in standard material dimensions.
In order to reduce material waste a more comprehensive planning stage is required, more emphasis
must be placed on recycling and other engineering materials and techniques need to be utilised,
such as modular buildings and prefabricated materials. These materials are designed to have high
efficiency due to the ease of installation and are readily available allowing builders to have more
flexibility in construction thus reducing material wastage.
Contents Executive Summary ......................................................................................................................................... 2
1.0 Introduction ........................................................................................................................................ 5
1.1 Scope of work ....................................................................................................................................... 5
1.2 Overview ............................................................................................................................................... 5
2.0 House construction analysis ..................................................................................................................... 5
2.1 House building process ......................................................................................................................... 5
2.2 House building process flow chart ........................................................................................................ 6
2.3 Construction material ........................................................................................................................... 8
2.3.1 Types of raw building materials ..................................................................................................... 8
2.3.2 Construction Goods .....................................................................................................................10
3.3.3 Construction Materials ................................................................................................................11
3.0 Wastage Investigation ............................................................................................................................12
3.1 Answers from Builders ........................................................................................................................12
4.0 Material variation ...................................................................................................................................13
4.1 Electronic estimation ..........................................................................................................................14
4.1.1 Software and applications ...........................................................................................................14
4.1.2 Excel spreadsheets ......................................................................................................................14
4.2 Sample Excel Spreadsheet ..................................................................................................................14
4.2.1 Assumptions ................................................................................................................................14
4.2.2 Function and purpose ..................................................................................................................15
5.0 Construction time waste management ..................................................................................................15
5.1 Construction “Downtime” ..................................................................................................................15
5.1.1 Definition .....................................................................................................................................15
4.1.2 Cost of Downtime ........................................................................................................................15
5.2 Downtime minimisation .....................................................................................................................16
5.2.1 Labour mediocre..........................................................................................................................16
5.2.2 Equipment ...................................................................................................................................16
5.3 Ordering template ..............................................................................................................................16
6.0 Construction material waste management ............................................................................................17
6.1 Reducing material waste by waste management ...............................................................................18
6.1.1 Waste hierarchy...........................................................................................................................18
6.1.2 Avoidance ....................................................................................................................................18
6.1.3 Reduce, Reuse and Recycle .........................................................................................................19
6.1.4 Treatment and Disposal ..............................................................................................................20
6.2 Reducing house waste by prefabrication ...........................................................................................20
6.2.1 Modular Buildings ........................................................................................................................20
6.2.2 Further discussion .......................................................................................................................21
6.3 Engineering Materials and Processes .................................................................................................21
6.3.1 “R-Flor” Particleboard Flooring ...................................................................................................22
6.3.2 AngleCut Roofing .........................................................................................................................22
6.3.3 SHADOW Clad ..............................................................................................................................23
6.3.4 Ply Floor .......................................................................................................................................23
6.3.5 HYPLANK ......................................................................................................................................24
6.3.6 TruFORM......................................................................................................................................25
6.4 Examples of home prefabrication and modular homes .....................................................................25
6.4.1 InsulWall by InsulLiving ...............................................................................................................26
6.4.2 Thirty storey building built in fifteen days ...................................................................................27
6.4.3 Target Zero Waste Home.............................................................................................................29
7.0 Green building.........................................................................................................................................29
7.1 What is green building? ......................................................................................................................29
7.2 Green approach ..................................................................................................................................30
7.3 Material efficiency ..............................................................................................................................30
7.4 Waste reduction .................................................................................................................................30
8.0 Builders Apps and Management Software .............................................................................................30
9.0 Conclusion ...............................................................................................................................................32
10.0 References ............................................................................................................................................34
11.0 Appendix ...............................................................................................................................................35
Tables and Figures Figure 1: Spreadsheet screenshot ........................................................................................................................ 14
Figure 2: Spreadsheet user input .......................................................................................................................... 15
Figure 3: Proposed ordering template ................................................................................................................. 17
Figure 4: Material waste data ............................................................................................................................... 17
Figure 5: Waste hierarchy pyramid ...................................................................................................................... 18
Figure 6: Waste management checklist ................................................................................................................ 19
Figure 7: R-Flor flooring from Carter Holt Harvey ................................................................................................ 22
Figure 8: SHADOWclad from Carter Holt Harvey .................................................................................................. 23
Figure 9: Ply Floor from Carter Hold Harvey ......................................................................................................... 24
Figure 10: PLYPLANK from Carter Holt Harvey ..................................................................................................... 24
Figure 11: truFORM .............................................................................................................................................. 25
Figure 12: InsulWall Structure .............................................................................................................................. 26
Figure 13: Broad Group Construction Process...................................................................................................... 28
Introduction
1.1 Scope of work The purpose of this project is to research and analyse house construction waste in terms of both
time and material. The intended goal of this project is to find ways which hardware supplier such as
Dalhsens can help builders become more effective and efficient with their projects.
1.2 Overview In order to determine the time and material wastage on site is to gain a better understanding of the
construction process. Thus, all the major steps involved in constructing a residential home is found
and shown in a flow chart. Furthermore, under each major step, the materials required in
completing each task are also analysed to gain a better understanding of the construction process in
a residential home. A sample spreadsheet is developed as a suggested method to help builders
better analyse material requirements for variations. An investigation through interviews is
conducted with the builders and sales representatives, from which the causes of time and material
wastage are determined. Therefore, time and material management techniques can then be
recommended in reducing wastage on site.
2.0 House construction analysis This section consists of the analysis of the house construction process. The breakdown of a house
building process is outlined with a description and also a process diagram is developed from this
information. Furthermore, a list of goods, materials and base materials are listed. The purpose of
this section is aimed at getting a more comprehensive overview of the house construction process in
order to find places for improvement.
2.1 House building process
1. Site preparation: This initial task involves clearing of the site and pegging out of the site by the surveyor. Sometimes retaining walls will also be built at this stage if required.
Rough staking, clearing, excavation, rough grading and erosion control.
2. Drainage and plumbing: In this step the drainage for the house is implemented. The plumber will need to lay plumbing that will be located beneath the slab of the development. This has to be done before slabs are put into place as the slabs go on top of the underlying plumbing network.
3. Slab: The slab piering is then completed as per the engineer’s specifications and plans and then the slab can be poured.
1. Prepare formwork 2. Set the corners square 3. Compact the road base 4. Divide the slab 5. Screed the concrete 6. Smooth the surface 7. Edge the concrete
4. Frames and roof trusses: The frames and roof trusses are generally prefabricated and prepared before being delivered to site, thus can be quickly erected.
5. Roof tiling or metal roofing: Tiles or metal roofing is laid as per client’s request. Pre-cut metal roofing is also available as discussed in section 5.3.2.
6. Windows 7. External Cladding: Brick, weatherboard or other (James Hardie Cladding)
8. Rough ins: This stage involves installation of electrical wiring and plumbing pipes.
9. Internal linings: The insulation is installed into the walls and ceilings then the plaster will
start on lining the walls and ceilings.
10. Lock up: Physical lock up of the building. Allows for work in doors avoiding weather effects and delays.
11. Waterproofing and tiling: The wet areas are water proofed in preparation for tiling.
12. Timber mould out: This stage involves the carpenters installing the skirting boards, architraves, door jams and doors and kitchen cabinets.
13. P.C. fit out: Prime cost items installation such as tap ware, bath, mirror, vanities etc.
14. Landscaping and Ground works. This step involves implementing items to the exterior surroundings of the house; which might include items such as patio, decks, paths, plants, post box, irrigation systems etc.
15. Practical completion
16. Handover
2.2 House building process flow chart
Site preparation
Pour in slabs
Implement Frames and
roof trusses
Plumbing
Waiting for slabs to
cure/settle
Install
foundation
Roof tiling of metal
roofing
Internal linings
Joinery
P.C fit out
Practical
completion
Handover
Lock up
Landscaping and
groundwork
Sometimes interchanged
due to builder
preference or experience
Water proofing
and tiling
Timber mould
out
2.3 Construction material This section establishes a clear overview of materials used in house construction in order to analyse
the possible sources and reasons of material waste. Commonly used materials are listed in three
different sub-categories, namely raw materials, goods and materials. These lists also give a better
idea of the vast amount of materials that go into a house construction and the potential of high
amount of wastage from multiple sources.
2.3.1 Types of raw building materials
Aluminium Uses - Mouldings, window frames Advantages - Strong, lightweight, can be recycled Disadvantages - Production is very energy-intensive and polluting. Earth-wise tips - Avoid, or use recycled aluminium. Brick (clay) Uses - Walls, paths, driveways Advantages - Versatile, good thermal mass Disadvantages - Production is energy-intensive and uses non-renewable resources. Earth-wise tips - Look for recycled bricks. Concrete Uses - Floors, walls, supports Advantages - High thermal mass, strong, durable, economical, resists termites and earthquakes Disadvantages - Production involves quarrying and creates greenhouse emissions; poor insulator, needs reinforcing. Earth-wise tips - Use autoclaved aerated concrete (AAC), which is lightweight, energy-efficient and non-toxic, or concrete made with recycled aggregate. Fibre cement sheeting Uses - Cladding Advantages - Low embodied energy, light, inexpensive, good thermal properties, can be rendered Disadvantages - Not as strong as some other options; associated with cheap housing and asbestos (no longer used). Earth-wise tips - Try lime wash as a surface treatment: it’s suitable and environmentally benign. Glass Uses - Windows, doors, skylights; bricks Advantages - Stable, long-lasting, efficient, recyclable
Disadvantages - Production is energy-intensive, uses non- renewable minerals. Earth-wise tips - Seek out recycled windows; buy energy-efficient new glass. Mudbrick Uses - Walls, floors Advantages - Source material can be found on site, long-lasting, biodegradable, high thermal mass; pest- and fire-resistant Disadvantages - Making bricks is labour-intensive; requires soil with high clay content; poor insulator. Earth-wise tips - Bricks can be purchased ready-made. Plasterboard Uses - Lining walls Advantages - Potentially recyclable, breathes, largely natural Disadvantages - Some plasterboards contain toxic chemicals and glass fibres. Earth-wise tips - Look for recycled plasterboard and non- synthetic boards with natural fixatives. Plastics Uses - Window frames, water pipes, gutters, floor and wall coverings Advantages - Light, durable, resistant to damp, water and pests Disadvantages - Made from non-renewable resources; production is energy-intensive and polluting; may off-gas. Earth-wise tips - Look for renewable alternatives; avoid PVC – opt for PVC-free polypropylene or polybutylene instead. Steel Uses - Frames, supports Advantages - Strong, economical, durable, recyclable Disadvantages - Production is energy-intensive and highly polluting; coatings are often polluting. Earth-wise tips - Buy recycled steel or opt for renewable timber. Stone and composite stone Uses - Walls, floors, supports Advantages - Abundant, durable, high thermal mass, economical if available on site; no toxic emissions Disadvantages - Non-renewable; extraction and transportation can be energy-intensive. Earth-wise tips - Use salvaged stone or products made with waste stone from local sources.
Straw bale Uses - Walls Advantages - Cheap, renewable, good insulator Disadvantages - Is bulkier than other materials; requires specialised construction. Earth-wise tips - Avoid chemical pest treatments and use eco-friendly render. Timber Uses - Floors, walls, supports and roof frames Advantages - Strong, easy to work with, versatile, potentially renewable, biodegradable Disadvantages - Some timber is non-renewable; often treated with toxic chemicals. Earth-wise tips - Use recycled wood or timber from sustainable sources, with no chemical treatments.
2.3.2 Construction Goods
Resources
o Silt Erosion & Rubbish control
o Toilet hire
o Retaining walls
o Treatment plants & trade waste
o Concrete pump
o Crane
Frames
o Prefab wall frames
o Frame hardware
o Carpenter frame
o Prefab roof truss
Wall
o Insulation
Roof
o Roof covering
o Fascia and gutters
Bathroom appliances
o Showers
o Sinks
o Toilet seats
o Mirrors
o Bathroom tiles
o Bath tub
o Taps
o Vanity
o Shower heads
Kitchen
o Stove
o Sinks
o Oven
o Range hood
o Kitchen bench
o Storage
o Taps
Rooms
o Lighting
o Flooring
o Storage
Services
o Hot water system
o HVAC
o Water
o Electricity
o Gas
o Telephone
o Sewerage
o Fire control
Garage
o Door
o Lighting
Security
o Doors
o Windows
o Locks
o Alarm system
Finishing
o Paint
o Trims
3.3.3 Construction Materials
Foundation
o Concrete
o Timber
o Steel framework
o Termite control
Flooring
o Timber
o Tiles
o Carpet
Framing
o Timber
o Steel
Roof trusses
o Timber
o Steel
Roofing
o Tiles
o Grout
o Colour bond
Brick work
o Masonry
o Grout
o Steel
Rough ins
o Wiring
o Switches
o Power outlets
o Fuse box
o Meters
o Piping
Internal linings
o Plaster boards
Timber mould out
o Door
External linings
o House wrap
3.0 Wastage Investigation After gaining a better understanding of the residential home construction process, the next step is to
investigate the causes of wastage of time and materials on site. Thus, meetings with builders are set
up whereby three builders are interviewed including: Frank from FRG Builders, John Brookes from
Jovand Homes and Ibro from Merima Building Solutions. All of the builders are interviewed with the
same set of questions (refer to Appendix) and provide with very different points of view with regards
to home building as well as some common answers as shown below.
3.1 Answers from Builders
Frank
Estimated completion for sample project: 6-8 weeks
Computer software not used due to cost, limited computer knowledge but open to any
recommended software from Dahlsens.
Materials wastage not much.
Materials wastage is managed by having more efficient measurements
Often over-order instead of paying extra for deliveries and waiting for re-ordering
Common design adjustment from home buyers are fittings, bathroom upgrades
Relationship with sales rep is positive with Cameron but the previous sale rep was not
helpful. Expects quick response times with quotes.
John Brookes
Estimated completion for sample project: 12 weeks
Computer software not used due to the lack of applicable software required for the specific
tasks therefore Microsoft project is used.
Materials wastage not much.
Materials wastage is managed by having a good planning stage and be on site frequently.
Often under-order instead of having wastage materials, happy to pay for extra delivery costs.
Common design adjustment from home buyers are extra room
Feedback on sales rep
o Must provide feedback
o Must have good communications
o Must follow through and adjust with orders
Ibro
Estimated completion for sample project: 3 months
Computer software not used because it is not very practical but currently using a template
like a timesheet
Materials wastage not much usually less than 10%
Materials wastage can be managed by having better/more efficient way of estimations
during planning stage
Common design adjustment from home buyers are extra room/partitions and bathroom
fittings
Good relationship with sales rep, likes to catch up.
Common Answers
Main influence in variation of time and cost: Weather
Deliveries are ordered/tracked: Phone
The project goes on halt when the orders are not delivered
No extra tasks done on site that were not planned during preliminary stage
Checklist is used to determine if the task is done on schedule
Extra materials are used for landfill
The affecting materials from design adjustments are determined with experience
From above, main causes of delays and material wastage can be deduced. It is found that the causes
of time wastage is due to weather and delivery related problems resulting in “downtime” during
construction. As weather is unpredictable, the problems associated with delivery can be controlled
and managed. For materials wastage on site, the main causes are found to be ordering mistakes and
difficulty in adapting with design changes from home buyers due to poor initial planning. From these
investigations, the time and materials management must be provided to reduce wastage on site.
4.0 Material variation This section looks at methods of estimating required material to cater for clients’ needs to design
variation. A standard method is required for estimating material needed and cost when it comes to
changes in design, often this is done tediously by builders back and forth looking at different
catalogues and finding quotes, which can lead to a large delay in project time frame.
4.1 Electronic estimation In order to have a more standard way of estimating that can avoid human errors and has reliable
efficiency and accuracy, it is suggested that electronic estimation is used. Electronic estimation can
come in forms of computer software, applications, spreadsheets etc. This sort of estimation can be
used in conjunction with the builders’ own estimations based on their experiences which will
provide for a form of comparison for a closer estimate. One thing to keep in mind is that these are
just estimates and results can vary accordingly due to different project conditions and different
algorithms used to code the estimation tool.
4.1.1 Software and applications
Software and applications are generally good for initial estimates as they have a set of materials
which they have been programed to estimate for, however when it comes to small variations in
design, these programs may not be flexible enough.
4.1.2 Excel spreadsheets
Excel spreadsheets are a good way of going about material estimation as it can be readily edited for
new specific materials, dimensions or any sort of variables that may only come with certain
providers, whereas the commercially available ones can only be used for those that they have been
programed for.
4.2 Sample Excel Spreadsheet For the purpose of this project, a simple sample excel spreadsheet was made in accordance to James
Hardy’s catalogue; using their products’ dimensions and dummy values for cost. This file is attached
in the USB handed in along with the report. Figure 1 below is a screen shot of the spreadsheet.
Figure 1: Spreadsheet screenshot
4.2.1 Assumptions
This spreadsheet was designed with simple algorithms and calculates wastage based on a few
assumptions:
Cost varies linearly
Dimensions of the components are not interchanged (i.e. during construction they cannot be
flipped around and used in the other direction)
Variation would only come in forms of extension
4.2.2 Function and purpose
This excel spreadsheet was designed around the idea that builders need a quick and effective way of
looking at different materials, standard dimensions, cost and wastage when their clients have a
specific design variation in mind. The builder would discuss with the client and find out the design
variations they desire, and the builder will then look at the length variation of the specific building
components that are involved, input the lengths into the spreadsheet. The spreadsheet would then
give values for the cuttings that are required due to standard dimension limitations and the amount
of wastage the cuttings would amount to financially, as shown in Figure 2 below. The builder can
then cycle through the different types of components and suggest to the client which types to use
based on the wastages that comes about due to standard dimension limitations.
Figure 2: Spreadsheet user input
5.0 Construction time waste management This section looks at time wastage in a house building process. Wastage in construction can be of
time wastage or material wastage. The causes of time wastages are looked into with more detail and
the financial drawbacks of specific issues are discussed.
5.1 Construction “Downtime”
5.1.1 Definition
Downtime refers to the periods of time wasted during construction often contributed by the
unavailability of construction materials and labour.
Downtime due to Labour: The periods of wasted time labourers spent not performing
construction activities such as during breaks and on tasks that have excess labourers.
Downtime due to Materials: The periods of time at which construction is paused due to the
unavailability of materials on site which are often caused by delivery problems including late
or missed deliveries, missing materials in a delivery and poor ordering schedules.
4.1.2 Cost of Downtime
Labour cost: Account for the full cost of direct and indirect labour with benefits, and include a share of all overhead positions in the plant, such as managers and support staff.
Product cost: The cost per unit of production at each stage in the process, along with the units per hour at the machine/profit centre, can tell you the value of the product lost during an incident.
Start-up cost (per machine, line, cell, and profit centre): Include energy surge costs, setup (materials and manpower), and percent of reduced production (units per hour lost), scrap
produced (include recycle costs and/or scrap value), quality inspection and rework costs), as well as other start-up costs.
Time: Calculate and record the time from the first occurrence of equipment breakdown to the time when equipment was back in full production.
Reduced production
Band-Aid costs: Figure in the costs of temporary fixes until the permanent fix is in place.
OEM, consulting, contractor costs: Include the annual fee or estimated cost per year for support during downtime.
Tooling: Calculate the replacement or rework cost for tooling (per occurrence).
Parts/Shipping cost
5.2 Downtime minimisation
5.2.1 Labour mediocre
Improving efficiency: Look at downtime, equipment usage, material procurement, materials
ready and available when needed, wasted effort, mistakes, training, standing around time,
smoking breaks, cell phone calls and wait time for their foreman to get them the information
they need.
Improving productivity: Watch the crew and look for areas to increase their effectiveness.
For example, watch the start times, finish times, breaks and lunch times.
5.2.2 Equipment
Improving equipment uptime: Develop plans and schedules for daily check-ups to ensure
spares, track availability and establish detail maintenance work planning.
5.3 Ordering template Due to the delivery related problems associated with time management, a more efficient ordering
process must be utilised in order to minimise time wastage on site. One way to accomplish this is for
the sales representative to utilise an ordering template or checklist. This will allow the sales
representative to assist the builder with the ordering of materials and goods; effectively reducing
problems with incomplete and/or delayed deliveries.
This ordering template consists of all the major steps for the construction of a residential home in
chronological order. Under each major step, there are general materials that need to be ordered to
complete the step of construction as shown in Figure 3 below (Refer to the Appendix for the full
template).
Figure 3: Proposed ordering template
As shown above, the template includes the start date and the delivery time of each task allowing the
sales representative to be kept to date with the construction process of the builders. Hence,
allowing the sales representative to be on top of all deliveries and also to remind the builder on
what they might need, thus reducing problems with stock checking and late deliveries.
6.0 Construction material waste management There is often a lot of material waste in construction. In 2006 to 2007, 43.8 million tonnes of waste
was generated in Australia according to Australia Bureau of Statistics (www.abs.gov.au) and 38%
came from the construction and demolition sector as shown in Figure 4 below. Out of the
construction and demolition waste, 43% was landfilled. This amounts to approximately 5.7 million
tonnes of construction waste as landfill.
Figure 4: Material waste data
6.1 Reducing material waste by waste management
6.1.1 Waste hierarchy
The waste hierarchy is one of the eleven principles developed for environmental protection
contained in the Environmental Protection Act 1970 shown below in Figure 5. The hierarchy provides
a sequence of action towards waste management from most preferable to the least preferable.
Figure 5: Waste hierarchy pyramid
The top three steps in the hierarchy are the most relevant and applicable to cases where
management of waste is required such as from household wastes, industrial wastes and commercial
wastes.
Industrial wastes that are generated from construction and demolition often result in huge deficit in
financial terms. Furthermore, the waste generated are often potentially hazardous to humans or the
environment if not disposed of properly. Excess wastes on the construction site can also result in
potential hazards on site.
6.1.2 Avoidance
Avoidance is the process placed highest/most preferable on the waste minimisation hierarchy chart.
This is where the most reduction in waste can be made. In order to “avoid” waste accumulation, lots
of planning has to be done prior to starting construction; during the design and drawing stages.
During the design stage, optimisation, minimisation and balancing designs will result in a reduction
of waste. In ground works, balancing the cut and fill volume will result in less fill soil required.
During the design stages, it is optimal to design structures around standard material sizes, which will
reduce the volume of wastes that is produced during construction from offcuts.
Building materials have to be carefully selected, particularly choosing materials and systems with
low waste rates, implementing modular and prefabricated construction materials should be
considered to minimise onsite waste. Looking for available recycled waste from nearby locations or
demolition works is a good way to avoid wastage and reduce in both material cost and
transportation cost.
Throughout the construction process, recyclable and recycled materials should be identified,
sourced and specified where they will be used. If the recycled materials are not immediately
reusable, they should be stored away such that damage caused by weather effects can be avoided.
6.1.3 Reduce, Reuse and Recycle
Reducing, reusing and recycling of building materials need to be conducted by implementing a waste
management plan as well as a suitable site management plan that supports it. To be able to conduct
the recycling procedure effectively, it will require specific instructions for the onsite construction
workers as it may not be their typical practice, thus the workers will have to be provided with
recycling, waste management and minimisation strategies during meetings or site inductions.
Planning of onsite waste separation and sorting during construction will be needed; where space
allows, which are then placed into colour coded or labelled waste bins to protect them from damage.
If possible, secure special bins at night where the site is not attended, to avoid theft and/or dumping
of rubbish in the recycling bins. The recycle bins can then be given back to suppliers as a trade-off in
financial terms or reused for future projects.
Figure 6 shown below is an example waste management checklist taken from sustainability Victoria
website.
Figure 6: Waste management checklist
For the full plan please refer to the website www.sustainability.vic.gov.au
6.1.4 Treatment and Disposal
Instead of material being directly landfilled, building waste products can be separated into different
bins to reduce tipping fees and increase recycling opportunities. For example landscaping and timber
waste can be placed in separate bins to be tariffed off and revenue can be produced from the waste.
Some waste can’t be reused or recycled and need to be landfilled. This must be done safely and
responsible, following any council regulations.
6.2 Reducing house waste by prefabrication House construction waste can be reduced by using methods of prefabrication and modular
construction. This section looks into different methods of construction that involves prefabricated
materials and some examples of prefabrication methods already used in past projects.
6.2.1 Modular Buildings
What are modular buildings?
Modular buildings or modular homes are buildings that are prefabricated in multiple sections called
modules. The modules are boxes constructed offsite then delivered to their location and assembled
for intended use.
Construction Process
The modules are constructed indoors and regularly inspected to ensure that they adhere to all
building codes. Assembly duration of modules can range from ten days to three months. The
completed modules are then transported to building sites, placement of modules range from several
hours to several days.
Construction Method
The modules are set onto the foundation and pieced together into a single building using a crane.
The modules can be pieced together in multiple ways such as side to side, end to end or stacked on
top of each other, thus offering a variety of visual and structural configurations according to client
needs.
Typical uses
The modular buildings are most beneficial when used for repetitive accommodations such as schools,
aged care facilities, mining villages, multi-level offices, apartment buildings and prisons.
Advantages
Fast construction – Faster return on investment
Improves safety by avoiding on-site risks
Indoor construction, increasing work efficiency and avoids weathering effects on building
material
Ability to service remote locations
Low wastage
Environmentally friendly construction process
100% reusable components
Flexibility in terms of expansion or extending
Quality consistency
Mitigation of theft of building materials from building sites
Reduced risk of exceeding planned budget and/or schedule.
Disadvantages
Transporting the completed modular building sections can take up a lot of space
Module sizes can be limited, affecting room sizes
Typical rectangular buildings can be aesthetically unappealing to home owners
Limited customisation range on building aesthetics
Limited by transportation size
Issues to be considered
Banks willingness to loan for modular homes
Resale prices
Service connections still required
Prices can be around the same in developed regions or higher than normally built homes
6.2.2 Further discussion
The reasons as to why people buy and own houses can be a deterring factor towards the appeal of
modular homes. The pride of ownership is the number one reason why most people yearn to have
their own homes. This implies that with the house ownership, the buyer will have complete control
of all aspects of the house down to the smallest details, however, having modular homes can mean
that as a home buyer you will have less say over what can be customised to your choice.
Furthermore, the idea of having a home is to provide a stable and safe environment for your family,
thus a house with a strong outer exterior is often what home owners want when building a home. It
is often presumed that bricks and concrete have better robustness over modules, whereas in fact,
modules can have material and structural properties that are on par or better than the traditional
construction methods. It can also be more reassuring for the home buyer to see the house built
piece by piece in brick or concrete over prefabricated modular pieces that are simply put together
on site, thus they would choose traditional building processes over modular simply based on that
feeling of reassurance.
This sort of mindset and ideologies about homes can often deter home buyers from wanting to build
a modular home despite the obvious benefits that they have in construction time, cost and
structural strength.
6.3 Engineering Materials and Processes In order to increase efficiency in the building process, the materials that are used is essential in
determining how efficient a structure can be built. Therefore, many of the next generation materials
are currently being used to meet the demanding requirements and at the same time provide high
efficiency. One such product is “R-Flor” particleboard flooring from Carter Holt Harvey shown in
Figure 7 which is easy to install and also readily available.
Figure 7: R-Flor flooring from Carter Holt Harvey
6.3.1 “R-Flor” Particleboard Flooring
“R-Flor” enables the commonly used and long established practice of building using the platform
construction method for suspended sub-floors; furthermore, flooring can be continued to be
installed in a manner consistent with the requirements of Australian standards.
As previously mentioned, the R-Flor material is easy to install and easily maintained. This is due to
the following:
No special tools or equipment necessary for installation
Service penetrations can be easily accommodated
Provides insulation – saves time, labour, materials and money
Risk of moisture entrapment in sub-floor insulation is avoided
Vermin-proof – No cavity space between flooring and insulation to house, un-invited vermin
Easy termite inspection – view of flooring and subfloor space not obstructed.
The full list of efficient materials and techniques can be found in Appendix.
6.3.2 AngleCut Roofing
AngleCut Roofing is a roofing system that is pre-cut in the factory to the specifications of the
builder’s house and is then laid on-site. This method ensures a faster way of installing roofing with
no on-site waste. The AngleCut metal sheets each come with a laying sequence number as well as a
laying guide for ease of installation. This method cuts out clean-up time as there are no off cuts and
also the working environment is a lot safer with no sharp bits lying around. The AngleCut technique
allows the builder to finish much faster and becomes more profitable though greater efficiency.
Key features and benefits:
Supplied pre-cut to length and angles
Available in a large range of colours and finishes
Quick installation
Supplied guide is easy to understand and follow
Suitable for use on 95% of new home roofs
6.3.3 SHADOW Clad
SHADOWclad from Carter Holt Harvey is a sustainable, stylish and versatile plywood cladding. It
offers a cost effective alternative to standard wall cladding as shown in Figure 8 below.
Figure 8: SHADOWclad from Carter Holt Harvey
Key features and benefits:
Easy to use – Lightweight and easy to handle on-site; plus no special tools required for
installation
Cost effective – saves on labours and paint costs with preprimed finish
Design flexibility – can be used on curved applications; dual cladding and bracing as well as
internal lining
Durable performance – H3 treated against fungal and termite attack.
6.3.4 Ply Floor
PLYfloor from Carter Holt Harvey is a strong, duable pre-sanded panel available in a range of
standard thicknesses from 15-25mm and is ideally suited for use in residential and commercial floors.
PLYfloor has machine grooved long edges with a plastic tongue to form a tongue and groove joint
between sheets as shown in below in Figure 9.
Figure 9: Ply Floor from Carter Hold Harvey
Key features and benefits:
Easy to use – Lightweight and easy to handle on-site; plus no special tools required for
installation
Superior strength – higher stiffness, strength and span than most other substrate systems
Product protected – available H2-S or H3 treated against fungal and termite attack and for
use in external or wet areas
Durable performance – proven to perform structurally for at least 50 years
Product quality – “product certified” for Engineered wood products association of Australia.
6.3.5 HYPLANK
Hyplank from Carter Holt Harvey is a strong yet lightweight laminated veneer lumber scaffolding
plank. It is now used extensively throughout the industry in place of conventional timber, and where
modular systems cannot accommodate the size and shape of the scaffolding requirement shown in
Figure 10 below.
Figure 10: PLYPLANK from Carter Holt Harvey
Key features and benefits:
Proven performance to AS 1577
Tough and long lasting
Lightweight and versatile
Sourced from managed plantation forests
6.3.6 TruFORM
TruFORM is structural Laminated Veneer Lumber (LVL) specially manufactured for use in structural
concrete formwork applications. It is manufactured in a controlled process to meet the
requirements of AS/NZS 4357 as shown in Figure 11 below.
Figure 11: truFORM
Key features and benefits:
Painted bright orange for product identification and moisture resistance
Easy length identification on site – ends are colour coded by length
Lighter and stronger than traditional timber alternatives
Faster and easier to install – enhances productivity and reduces forming costs
Use results in an improved concrete finish – straight and true
6.4 Examples of home prefabrication and modular homes Many companies in the world are already adapting the prefabrication and modular housing method
to save both the clients and themselves on time and cost. Below are a few examples of
prefabrication materials and some construction projects that used prefabrication and/or modular
building.
6.4.1 InsulWall by InsulLiving
What is InsulWall?
InsulWall is an Australia product. It is a load bearing insulated wall panel developed by BONDOR in
conjunction with BlueScope Steel. This product is designed to reduce or eliminate the difficulty and
inaccuracy out of home construction. This method of construction is currently used for buildings up
to two stories tall.
Construction Process
The InsulWall pieces are transported to site and assembled on site according to design. Rails are
placed on the foundations where the walls are to be aligned. Sealing products are applied to the
joints of the wall pieces afterwards to ensure an enclosed environment. The roof is assembled
similarly to the walls, due to the light weight of the pieces, the roof components can simply be lifted
up and secured without a need of a crane. The InsulWall structure schematic is illustrated below in
Figure 12. The InsulWall comes with pre-cut service ducts ready for electrical conduit. Fascia
flashings are simply fixed with screws and rivets and ready for gutter installation.
Figure 12: InsulWall Structure
Construction method
The wall pieces are then fixed onto the rails by simple screw fixtures and rivets. The InsulWall
components interlock with each other using a slip joint system that uses both male and female joints.
Advantages
No frames requires
Lightweight construction
Highly insulated ( 9 star energy rating)
Fast construction
Leaner
Reduces reliance on multiple trades thus eliminating some possible factors of delay
Ongoing energy savings
Replaces multiple wall components: frames, brick, plasterboard, insulation
Replaces multiple roof components: trusses, roof sheets, ceiling, insulation
Simplified construction process
Downsizing, renovation and recycling is easy
Avoids termite damage
Lesser deliveries needed
Fully reusable, recyclable and non-toxic building materials
Easy extension and renovation
Disadvantages
Limited to conventional house shapes (rectangular & triangular)
Limited to two storey designs
Electrical services’ wirings are limited to preformed ducts positions in the walls
Limitations to component dimensions
6.4.2 Thirty storey building built in fifteen days
The 30 storey building was built near Dongting Lake, Hunan Province in China by a Chinese
construction company called Broad Group. In order for fast construction, all the sections of the
building were prefabricated in factories and shipped to the site before construction. The structure is
designed to withstand a 9.0 magnitude earthquake.
According to an article written by Lauren Hilgers on www.wired.com ; in which he interviewed the
chairman of Broad Group, the 30 storey building are built in sections each measuring 15.6 by 3.9
meters, with a depth of 45 centimeters.
Construction process
The illustrations below in Figure 13; by Jason Lee, details the process of how the sections were
delivered and how the building was built.
Figure 13: Broad Group Construction Process
Advantages
Fast construction
Low CO2 emissions
Low energy consumption
Low to no wastage
Sections can be recycled and reused
Disadvantages
Not physically appealing
Labour intensive (200 labourers)
Further discussion
The speed of which this building was constructed is also relative to the cost of labourers in the
country. In comparison to labourers in China, local labourers in Australia have much higher wages;
therefore it would be impossible to hire 200 labourers to be on site simultaneously, moreover, to
have such high number of labourers on site at the same time, some OH&S laws may have to be
considered. Furthermore, it seems that China has different laws which allow non-stop construction
throughout the night, which allows expedition of the project. Thus if an exact project is undertaken
in Australia, the conditions of which it will be built will be completely different and will not be as fast.
However, the techniques of which Broad Group have used to construct this thirty storey building
such as full prefabrication of all sections of a building is quite innovative.
6.4.3 Target Zero Waste Home
“Target Zero Waste Home” project is conducted by RMIT’s Centre for Design collaborating with
Burbank Homes and the Housing Industry Association to develop ways of avoiding housing
construction waste.
The project is funded $1.3million by Sustainability Victoria’s Beyond Waste fund. The project’s
purpose is to identify better ways of building houses to stop construction waste being sent to landfill.
An initial audit was found that nearly nine tonnes of waste was generated during the construction of
a typical single-storey brick-veneer home. It was also found on average that each new house
constructed in Victoria produces 5.8 tonnes of waste on average.
The home will be built using innovated construction processes that are expected to reduce waste to
landfill by at least 80% (4.5 tonnes of waste per house). It is expected that the project will exceed its
initial targets. Burbank Managing Director Jarrod Sanfilipo said that the 80% construction waste goal
will be achieved through a combination of avoidance, reuse and recycling (Thus implies that it’s still
using the typical house building process, not using modular or prefab).
The project is located at Lot 122, Ladbroke Street, Melton South VIC 3338 (Lend Lease’s new
Atherstone community in Melton)
The construction began on the 18th of August 2013.
7.0 Green building This section looks at a structural design concept called green building. For the purpose of this project,
the focus will be on the reducing waste and improving material efficiency. Aspects of this design
concept, however, green building covers a much wider field of control and management.
7.1 What is green building? Green building; also known as green construction or sustainable building, refers to a structure that is
designed to be environmentally responsible and resource-efficient throughout the building’s life-
cycle. This includes design, construction, operation, maintenance, renovation and all the way to
demolition.
7.2 Green approach The design concept of a green building does not only revolve around the structure itself, but it is also
designed to reduce the overall impact on aspects such as human health and the natural environment.
This is done by:
Efficiently using resources
Reducing waste, pollution and environmental degradation
7.3 Material efficiency Material efficiency in green buildings is often achieved by usage of sustainable materials. Materials
such as dimension stone, recycled stones, recycled materials. Plants such as bamboo and straw are
also considered ‘green’ as they are rapidly renewable by nature.
7.4 Waste reduction Waste reduction in during green building construction phase is aimed at reducing the amount of
material going to landfills. In America, the Neutral Alliance created the website
www.dontwastewood.com to help regulators, developers, contractors, builders and owners get
information about recycling wood.
Compost bins are sometimes placed for occupants to help reduce the amount of waste generated
that go into landfills.
In Australia, websites such as www.sita.com.au offer information about timber recycling, and
criterions for recyclable timber. The website offer some useful tips to help deal with offcuts and
unused timber, such as using them for smaller projects and/or contacting local educational facilities
to let them have the small offcuts for art and craft activities.
8.0 Builders Apps and Management Software In order to assist builders with the management of their projects it is beneficial for them to utilise
management software and also to use applications on mobile devices to make quick and efficient
calculations. Below is a list of common apps and software with their key features highlighted.
BuilderTREND ($99-$149+/mo Available for use on desktop and mobile devices) Demo Available
BuilderTREND is a construction management system for house builders and remodelers. The
software enables builders a better building experience for their clients and associates. It helps
provide the user with real-time access to scheduling information, documents, photos, change of
orders and more. BuilderTREND provides web-based builder software that optimises communication
between the builders, their customers, vendors and subcontractors.
Key features:
Online Schedule Management
Change Order Management
Document and Photo Management
Selections Management
Warranty / Service Management
Improving Sales
Project Communication
Co-Construct (Demo Available)
Con-Construct has very similar features to BuilderTrend’s software but allows more custom features
for the builder. This software is suitable for a builder that has variable projects that are very custom.
The mobile app is powered by the company’s software but is branded with the builder’s logo and
colour scheme which is all synced to the web-based software.
Selection Sheet
Scheduling
Client Communication
Budgeting
Change Orders
Expense Tracking
Cost-Plus Management
Punch Lists
Photo and File Sharing
Website Integration
Client Access
Subcontractor Access
Home Builder Pro Calcs (Price: $5.49 – iTunes App Store)
This App consists of a large variety of calculators that allows the user to quickly and easily solve a
variety of necessary house building calculations including time and cost estimates. The App is mainly
designed for builders to be able to make quick onsite estimates on the go, calculations can be saved
and emailed.
Key calculators and features:
Calculators for carpet, drywall, wall covering, tile, and paint
Calculators for asphalt, concrete and paver bricks
Calculators for foundations including soil, grading and steel reinforcement
Framing calculators including balusters, joists, studs, siding and stairs
Roof framing and roofing calculators for rafters, ridges, pitch, trusses and metal sheets
Calculator for wood and materials
Calculators to help you understand and manage project timing and deadlines.
Numerous time and cost estimators
Also includes glossary and measuring tools
HandyMate PRO ($3.00 – Google Play Store)
This App is a collection of builder and estimation tools designed for the user to help solve common
building estimates. This App is very similar to Home Builder Pro Calcs but is designed for the Android
platform.
Key calculators and features:
Wall Estimators for brick, tile, panel, wallpaper, weather board, paint and render.
Floor Estimators for tiles, board/deck and carpet
Ceiling Estimators for panel, paint, plaster
Roof Estimators for tiles, sheets, painting
Ramp Estimators for tiles, timber boards, carpet, paint
Ramp and stair calculator
Concrete calculator
Unit Convertor for Length, Area, Volume, Weight, Temperature units
Geometry Calculators
Linear Calculators for triangle, arch and ellipse
Area Calculators for triangle, parallelogram, trapezium, circle, ellipse, sector
Handyman Calculator (Free– Google Play Store $4.75 to purchase and remove adds)
This app has many simple construction and home construction calculators to help the user make
quick calculations and estimates. It also incorporates a notepad for storing measurements and
results.
Key calculators and features:
Floor Estimators for tiles, floorboards and carpet
Wall estimators for paint, tiles, wall paper, brick, weatherboards
Concrete, Brick, Block, Mortar and Sand Calculations
Lumber, Concrete and Asphalt calculator.
Length, Area and Weight conversion.
Wall Framing Calculator
Air-conditioning and heater calculator
Roofing calculator
Fencing and landscaping tools
9.0 Conclusion
In order to gain a better understanding of the home construction process, all major steps involved in
building a home were investigated and shown in a flow chart. This combined with the investigations
of the materials needed under each step enabled for better understanding of the construction
process and allowed the causes of time and material wastage to be determined. For time
management, it was found that the main cause of delay in time is the “downtime” when
construction is in idle whereby the majority of this idle time on site was found to be caused by
delivery issues. As for the materials wastage, the factors causing material waste on site consisted of
ordering mistakes and difficulty in adapting with design changes from home buyers. Consequently,
the methods of reducing wastage were recommended such as a better ordering process for time
management and better planning for materials management.
10.0 References 1. Chivers, J. 2012. The 13 steps in the construction phase of building a new home. Available at:
http://www.propertyobserver.com.au/g, [Accessed: 4 Feb 2014].
2. Epa.vic.gov.au. 2014. Waste in Victoria | Environment Protection Authority | EPA Victoria.
[online] Available at: http://www.epa.vic.gov.au/your-environment/waste [Accessed: 4 Feb
2014].
3. How to lay a concrete slab. 2014. [blog] 01/01/2014, Available at:
http://www.readersdigest.com.au/concrete-slab [Accessed: 4 Feb 2014].
4. Insulliving.com.au. 2014. Home l InsulLiving: Australia's Insulated New Home Specialists |
InsulLiving. [online] Available at: http://www.insulliving.com.au/insulliving/ [Accessed: 4 Feb
2014].
5. KMC Crew. 2011. Why Do People Actually Buy a Home?. Available at:
http://www.keepingcurrentmatters.com/2011/07/19/why-do-people-actually-buy-a-home/
[Accessed: 4 Feb 2014].
6. Merz, S. K. 2014. Modular construction the way of the future. Available at:
http://www.globalskm.com/Insights/Achieve-Magazine/Issue3-2010/article6.aspx [Accessed:
4 Feb 2014].
7. Readersdigest.com.au. 2014. Types of building materials - their uses, advantages and
disadvantages | Reader's Digest | Reader’s Digest Australia. [online] Available at:
http://www.readersdigest.com.au/types-of-building-materials#sthash.EI58sxJr.dpuf
[Accessed: 4 Feb 2014].
8. Weintraub, E. 2014. Eight Reasons to Buy a Home. Available at:
http://homebuying.about.com/od/buyingahome/bb/buyhome.htm [Accessed: 4 Feb 2014].
9. http://www.wired.com/design/2012/09/broad-sustainable-building-instant-skyscraper/all/
10. Green Building Council of Australia. 2014. Green Building Council of Australia. [online]
Available at: http://www.gbca.org.au/ [Accessed: 17 Feb 2014].
11.0 Appendix
Carter Holt Harvey
R-Flor
STRUCTAFLOR
PLY Floor
Pryda
Bracing Guide
Connectors & Tie down
Hangers & Truss Boots Guide
Lintel Guide
Corinthian doors
James Hardie
Fence installation
HardiePanel Flooring
Shadow Clad
Job Name: ________________ Date: __ /__ /__
Builder Name: ______________
Unit Number (if applicable): _________
Tasks Start Date Delivery time Task Duration Check
Preliminary Preliminary Work
Site Preparation Detailed Excavation and
Sand Up
Sand up for main house Toilet Hire
Temporary Fencing Electrician initial Site
Works
Drainage Plumbers Rough in Plumber Gas Fitter
Plumber & Drainage
Slab Slab Hardware Slab Concrete
Termite Treatment A
Frames and Roof Trusses Pre-fabricated Wall Frames
Frame Hardware Prefabricated Roof Truss
Carpenter Frame
Roof Tiling or Metal Roofing Roof Covering
Fascia and Gutters
Windows Windows
External Cladding Painter
Carpenter Cladding
Rough Ins Electrician
Internal Linings Wall & Ceiling Linings Termite Treatment B
Insulation - Wall Batts Insulation - ceiling
Lock Up Garage Doors
Lock up
Joinery
Tasks Start Date Delivery time Task Duration Check Carpenter joineries
Water Proofing and Tiling Waterproofing Ceramic tiling
Timber Mould Out External Door Locks
Finishing hardware & Internal Door Knobs
Finishing Timber & Internal Door
Lock Up Hardware, Eaves & Soffit Sheets
Fly Screens or Security Screens
Carpenter Lock & Soffits
P.C Fit Out Baths & Spa Baths
Sanitary Ware Shower Screens - Mirrors &
Doors
White Goods Light Fittings Water Tanks
Plumbers Fit Off External finishes
Concreter External External Concrete Pump
External Concrete Hardware
External Concrete External Concrete Sand
Fencing & Timber Retaining Walls
Clothes Hoists / Letter Boxes
Handover
