ABPL 20042 Residential Construction and Structures
House Watch Report Traditional brick-veneer with concrete slab, cut-in roof trusses with roof tiles
Sourced: by Di Carina SONG at Altona 50 Pier Street on13 August 2011
LECTURE:
Jim GIORGIO
Toong-Khuan CHAN
Di Carina SONG
383403
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CONTENT PRECONSTRUCTION PHASE ADMINISTRATIVE PROCEDURES 1. Design the house-------------------------------------------------------------------------------------7 2. Employ consultants----------------------------------------------------------------------------------8 3. Get the planning permit----------------------------------------------------------------------------9 4. Get building permit----------------------------------------------------------------------------------10 5. Specification and Schedules -----------------------------------------------------------------------15 6. Deal with taxation, insurances, contractor and subcontractor---------------------------16 7. Costing and budget----------------------------------------------------------------------------------17 8. Administration control------------------------------------------------------------------------------17 BUILDING SITE PREPERATION--- rough site work 1. Organization the site for construction ---------------------------------------------------------18 2. Site preparation -------------------------------------------------------------------------------------19 3. Excavation ---------------------------------------------------------------------------------------------20 4. Site utilities and basic services connection----------------------------------------------------21 5. Sewerage system and surface water drainage -----------------------------------------------22
CONSTRUCTION PHASE THE FOUNDATION---footings and slabs 1. Design foundation criteria and choice-----------------------------------------------------------25 2. Footings- Waffle Slab--------------------------------------------------------------------------------26 3. Steps to establish waffle slab ----------------------------------------------------------------------27 4. Waffle slab fact sheet( AS 2870, reinforcement and width of stem)---------------------28 5. Use of Damp Proofing membrane for slab protection --------------------------------------30 6. Deal with steps in Footings ------------------------------------------------------------------------31 7. Problems solving and issues in real construction --------------------------------------------32 8. Comparison between concrete slab on ground and strip footing -----------------------34 STRUCTURAL FRAMING ( platform framing) -------------------------------------------------------35 1. Timber frame establishment----------------------------------------------------------------------36 2. Floor ( timber floor+ concrete slab floor)------------------------------------------------------37 3. Timber frame erection and annotation--------------------------------------------------------38 4. Nailing in timber frame wall and spacing ------------------------------------------------------39 5. Bracing--------------------------------------------------------------------------------------------------41 6. Sheathing wall ----------------------------------------------------------------------------------------42 7. Timber selection ------------------------------------------------------------------------------------43 8. Window------------------------------------------------------------------------------------------------ 44 ROOFING AND SIDING( Truss roof) -------------------------------------------------------------------47 1. Conventional frame roof and reused pitched roof-------------------------------------------49 2. Traditional roof construction sequence and techniques -----------------------------------51
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3. Australian conventional roof construction--------------------------------------------------------52 4. Tile installation------------------------------------------------------------------------------------------- 53 5. Construction of Roof Edge ----------------------------------------------------------------------------54 UTILITIES AND INSULATION 1. Services- Plumbing --------------------------------------------------------------------------------------55 2. Services- Heating and cooling ------------------------------------------------------------------------56 3. Services- Electricity Wiring ----------------------------------------------------------------------------56 4. Insulation Installation-----------------------------------------------------------------------------------57 5. Brick Work-------------------------------------------------------------------------------------------------60
SERVICES PHASE Finishing the wall and floor--------------------------------------------------------------------------------- 63 Finishing the interior------------------------------------------------------------------------------------------64 Services 1 electricity ------------------------------------------------------------------------------------------64 Services 2 Gas and water ------------------------------------------------------------------------------------66 Services 3 Sewer and Stormwater------------------------------------------------------------------------ 66 Fixing -------------------------------------------------------------------------------------------------------------67
Appendix------------------------------------------------------------------------------------------------------------ 69
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INTRODUCTION & EXPERIENCES The house watching assignment aims to provide students opportunities to digest the knowledge they gain in lectures. By visiting domestic scale construction houses and observing the assembly process of Australian typical brick veneer houses, I form a blue picture of how the light timber frame houses( brick veneer houses)are fabricated in real life and what are the problems that a builder and house owner might face within real construction environment. During my observation, I constantly refer back to the standards and legal documents such as Australian Standard and Building Code of Australia, which enable me to explore and reinforce the understanding about administrative and legal obligations in building industry. The houses been observed were scattered around the suburban area of Melbourne where new houses are emerging prosperously.
Site 1: 50 Pier Street Altona --- Timber Frame+ insulation+ services ( Platform Framing ) Site 2.Lot 10 Hogans Rd. Tarneit --- Tile+ Services Rough In Site 3. Cloverdale Rd. Tarneit --- Site Preparation+ Footings+ Concrete Slab Site 4.Tarneit --- Timber Frame Construction Site 5. 38 Sea view Crescent, Blackrock --- Services Phase + Fittings
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INTRODUCTION & EXPERIENCES The 5 observed houses are under various stages of construction and nearly all the trades involved in building industry, say the excavator, the drainer, the concreter, the bricklayer, the carpenter, the roofer, the liner fixer, the renderer, the electrician, the plumber, the tiller, the painter, etc., could be traced during the process of construction. The 5 houses are all built in a cottage construction called brick veneer. These houses are constructed with a timber frame, around which clad and tie a one- brick- thick skin. Brick veneer house take the best of both timber frame house and all- brick construction because if its flexibility and economic-friendly –system. The system has being refined a lot in Australia since 1950s onwards. Brick veneer house allow for a clear separation of sub-traders, which is the main reason why so many Owner Builders would choose this construction method. I fortunately have one of my visited houses built by an OB, an Owner Builder as an architect. Having being worked on the construction of the house for two years, he carried out most of the work by himself while hiring isolated subcontractors separately. For the Pre- construction phase in my report, I mainly focus on how he manage to get start to build his house (how he designed his house, how he prepared the required documents to get building permission\approval from local authority: preparation drawings, schedules and building specifications? what else did he prepare? How he get the Owner Builders License? Did he have home warranty insurance? Did he register with the Australian Taxation Office?) How he leisure different trades and how he manage the time process. Finally, I focus on the administrative procedures and basic regulation associated with the connection of services to the house. How he notify authority to connect the services to his house, how he designed these services to apply BCA and how he designed his house into an energy saving house to achieve 5stars in First Rate. For the Construction Phase, I put the construction progress in sequence by emphasizing on details of different construction phases. This will enhance my knowledge gained in lectures.
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Preconstruction Phase
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*****************************Preconstruction Phase**************************
ADMINISTRATIVE PROCEDURES 1. Design the house
Before starting to build the house, the preliminary step is to design the house. Many of the conventional building plans are directly adopted from a building plan service sector, such as building information centers, offer home plan services. Otherwise, architects could be employed to design unconventional house. The copy right of the plans belong to their designers for lifelong and 50 years after their death. These plans can’t be used without special permission.
In the design stage, architect will produce many sketches to communicate with the customers.
There are many design principles for residential house: Perspective drawing and model produced by the designer of one of the houses I visited.
Consider every stakeholder living in the house by justifying their needs Room function, quality requirements for different rooms, relationship between rooms Appearance Budgeting
-Normally, higher and wider rooms, nonstandard windows, large section skirting and cornices and multiple power points blow out the price. Models efficiently demonstrate the appearance of the building. (For residential houses, kitchen and living rooms are given more consideration, for they are the main rooms that most family activities are held. Architect will chat with the customer, especially the wives, to make sure they like the house. Then, architects could move on to work on the house plan, site plan and landscape plan.)
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2. Employ consultants such as, surveyors, valuers and structural engineers Consultants are those who have special knowledge in building process. Nowadays, there is increasing trend that OBs are obliged to employ some of the consultants. As in my visited house’s case, where the owner is an architect, he himself acted as the designer of the house. However, employing a surveyor is the necessary step. Local councils historically provide the building survey services, while legislation has been introduced to allow private building surveyors to issue building permits. This system is known as ‘private certification’ and consumers now have the choice of engaging a private building surveyor or seeking the same service from a municipal building surveyor. Building surveyors do much more than just issue building permits. They can carry out inspections of established buildings to determine their existing condition and the level of compliance with safety standards. Land surveyors are engaged with owner builder for 3 situations during the site development 1. Boundary survey: conduct upon purchase of the property 2. Building setout survey: to position the building in relation to building alignments and boundaries 3. Check survey: to ensure side boundary and setbacks are not changed( whether the pegs changed)
In addition to having recognized qualifications, a surveyor must be registered and must have appropriate insurance. Also, structural engineers are employed to work out structural details. Engineers also conduct the soil test and site investigation.
Soil Test Sample
Site investigation and soil test are necessity for surveyors to issue the building permit. The consumer and builder sign a Preliminary Building Agreement to carry out the soil test. The site should be classified according to AS 2870.
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3. Get the Planning permit The engineering drawings, landscape and house plans and the environmental impact statements are essential documents in getting a plan permit, which is a preliminary step to get a building permit. LANSCAPE DRAWING ENDORSED BY COUNCIL
ENGINEERING DRAWING ENDORSED BY COUNCIL Planning permit
Planning approval and building approval are two separate processes. The planning approval process involves assessment of a proposal to use or develop land against the rules in a planning scheme. The planning process is mainly concerned with the impacts of a proposed use or development upon neighboring land. Issues could be whether the house is too high to shadow the neighbor, whether the house suits the street scape?
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4. Then, Apply to build the house ------- Prepare documents to get building permit The Building Act 1993 requires that building work must be subject to the issue of a building permit prior to that work commencing.
These documents are required by Authorities to communicate the basic information about the building, such as the quantity and quality of the materials, the layout, the assembly and components of the building. The Building Act prescribes a penalty of $10,000 for any persons who carry out work without a permit.
Required Documents in gaining building permit loosely fall into:
Working drawings, including layouts, assemblies and details Specification, including the specification and schedules Some other documents may also be required, such as:
Perspective drawings and models of the proposed building Environmental Impact Statement Heritage report and evaluations Shadow diagrams and solar access chart Landscaping plans 6 Stars for First Rate Engineering Report
Some of the documents have been required during the application of planning permit Building permit involves an assessment of a proposed use or development against the Building Code of Australia and the Plumbing Regulations. A building surveyor could issue certificates of compliance for the BCA. 10
The building approval process mainly involves issues such as:
Is the building soundly constructed? Have adequate fire protection measures been installed? Is the building capable of receiving adequate levels of light and ventilation? Is the building property sewered and drained? Are the building's features safe for users?
EXEMPTION: The building regulations recognize that some building work does not require a building permit. Examples of exemptions include - Construction generally under $600 -pergolas associated with houses less than 20m2 in area
House section and elevation provided as part of the document applying building permit
- Garden sheds with a floor area less than 10m2 - Repair work done for maintenance purpose, such as replacing rotted weatherboards. - Alterations to a building if the building will not adversely affect the structural soundness of the building and will not increase or decrease the floor area or height of the building - Construction and demolition of a freestanding Class 10a building (such as a shed, carport or garage)
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Attached Building Permit Exemption
For more information regarding exemptions, builder should consult building surveyors. Source from Building Commission, Registered Building Practitioner, Practice Notes,2008-32 12
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Registered Building Practitioner Certificate Information shown: Builder’s registration number Builder’s contact number Surveyor’s name (Municipal building surveyor) Surveyor’s contact number Building Registration number Issue date *Builder registration and building permit for OB
*IF THE BUIDLING WORK IS MORE THAN $5,000, THEN THE BUILDER MUST BE REGISTERED
IN ONE OF MY CASES FOR OWNER BUILDER Owner-builders must obtain a Certificate of Consent for any domestic building work with a value over $12,000 in order to obtain a building permit and they can only obtain a building permit for one home in a three year period.(Application is $85.15) However, for those who carry out work value lower than $12000, they are exempt from getting OB Certification, but they still need to provide documents to get Building permit. Also, Certificate of Consent is not required if the OB is a registered commercial or domestic builder, registered demolisher or a registered architect with the Architects Registration Board of Victoria.
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5. . Specification and schedules Specification make up the normal building contract and it involves with the quality of the materials and labor to be used in building process. When preparing specification, builder generally need to consider the site conditions, conduct site investigations and test the soil. Specification is a document that gives authorities information about whether the proposed building satisfies quality standards required by building regulations and laws. Thus builder need to ensure the house at least beat the minimum standard listed in BCA. If the builder is an OB instead of a building practitioner, and if he borrow money from a lending authority, then the quality of the house should satisfy the authority. Some lending authorities can provide OB with standard specification that has been prepared to suit various types of construction and meet the minimum quality standards. .
Schedule produced by OB
In my visited house’s case, the owner himself is an architect. He prepared his own specification. Also, he conveys part of the information such as window and door by means of schedule.
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6. Deal with taxation and insurance, contract and subcontractors -GST: generally 10% and applies to all goods and services used in construction of houses -In Victoria, contracts are required for work over $5000. The contract includes a start date, a finish date and details about progress payments -If the building work is over $12,000, then the builders need to cover warranty insurance for the work -Builders are required to take out basic workers’ compensation policy even the workers are employed by contractors Builders have an administrative role to list out every sub-trade that they are likely to employ and leisure the different sub-trades. For owner builder, they could determine whether they are willing to employ subcontractors or not, referring to the table below:
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7. Costing, budget
One of the most important thing in pre-construction phase is to sort out the costing and budget. Builders could estimate their cost by listing the construction activities in a chronologically manner. A costing check list is attached to demonstrate this method. (* Costing roughly = cost of materials+ labours+insurances+equipments (hire or buy) +authorities fees+ documentation and application fee) 8. Administration control The administration control comprises the time, material, labor and money control. Builder need to plan these elements well before they actually construct the house. There are many authorities that builders have to deal with, among which some of them are important: Local municipal council Water supply
Submit applications and pay rates Tap into the main( need to be carried out by a licensed plumber)
Sewerage drain
Telephone, TV, internet connection
Inspection of sub- sewer drains may be required before they are covered, get the certificate of compliance after the completion of pluming and sewerage installation Need to contact the engineering department of municipal council Installed by licensed electrical tradespeople, inspection needed after installation Contact private telephone connection company for connection to the system
Scaffolding regulation
Inspection needed before scaffolding is used
Stormwater drain Electricity supply
************************************************************************** In conclusion, during the administration procedure, both builders and consumers are involved in many legal and technological matters. Documents need to be prepared, timelines and budgets should be considered, and builders need to contact different consultants, authorities and tradespeople.
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ď ś BUILDING SITE PREPARATION ---Rough Site Work Preparation of the building site for construction is the first physical step in the building process. The area where the house is to be seated is to be cleared, the building corner is to be staked, and the hole is to be excavated for the foundation. Utilities such as water, gas , electricity and telephone lines are extended to the building site. 1. Organizing the Site for Construction Before construction, it is important to plan the access routes and storage location so that trucks are easy to drive into the site, heavy equipment are easy to load on the soil, pegs won’t be moved accidentally, and construction activity is not disrupted.
This is one of the houses I visited. As illustrated above, the site is well organised for construction. Pickup trucks and vans ware easily park on around the site, and the waste pile is stacks in the corner of the lot.
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2. Site preparation At this stage, land surveyor will mark the corner of the property and notes the relative elevation to be used for FL of the house. Then the site used for building will be cleared.
Boundary known as the ‘property lines’ is established by surveyors. Builders can fence the area and conduct construction work within the site.
Lot boundary Series of stakes are located to mark approximately the corner of the building’s foundation Workers clear the major vegetation within the site before starting construction.
The precise location of the building (Site set out) is established by using the batter board system. 1. Lay out the perimeter of the project by accurately driving stakes at the corners 2. Because the stakes will be lost during excavation, batter boards are used to Batter boards are located at least 4 feet outside the pegs at the corner of the foundation to allow for excavation. Strings are stretched out between batter boards. 3 Dangle a plumb bob over the stakes and mark the outside dimension on the batter boards with a nail, so lines can be restrung whenever needed. 4 Later a plumb bob is suspended again from the intersecting strings to locate the corners of the walls.
Diagonal strings are equal when site set out is square. AA-DD=BB-CC 19
Example : Site Set out in construction Site & batter board system benefits in the future
Outside surface of the base wall is determined by stretching the strings. A plump bob might be suspended to the intersection of the strings to decide the location of the wall corner
Stakes or pegs with nails are located at least 4 feet outside the pegs at the corner of the foundation. Restring with the nailed pegs could determine the corner of the base wall.
3. Excavation After the site is cleared and the precise location of the base walling is established, excavation is conducted.
The excavator first removes all soil containing organic matters. The mixture of topsoil and plants is stocked for future back fill.
Excavation to the correct depth. The depth corresponds to the level at which the bottom of the building’s foundation will rest on. Contractors and excavators work as team to measure the depth
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4. Site Utilities and Basic Services Connection For the convenience of the contractor, temporary utilities need to be installed. Temporary weather tight electrical panel is erected for the construction equipment, especially from the time when footing is to be made. Local community will extends a permanent power liner into the site to supply electricity. Temporary electrical panel with meter was set up and connected to a power supply before framing of the house began.
Water is also needed early in the site, especially for concrete block foundation. Portable water is collected, purifies and distributed to customers through water mains buried in the street. Builders dig a trench to the property line and lay the pipe in it. The pipe connects the water main and the house with a water meter measuring the amount of water consumed.
Temporary chemical toilet facility is a fixture on the site until the job is completed.
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5. Sewage System and Surface Water Drainage
The building sewer is typically a 3- or 4inch plastic pipe sloping away from the house. The building serer runs from the house to the inlet of the septic tank. The outlet pipe is lower than the inlet pipe and the out let is lead to the drain field. reinforced concrete septic tank
Inception sewer pipe
The location of the septic tank and drain field are restricted by the governmental authority. Codes generally specify that the depth of the septic tank should be deep enough and should keep a minimum distance from the house. It is not suitable to be located under roads and driveways where vehicles usually travel.
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After the excavation, sewerage pipes are located in the prescribed location.
Water drainage is a big issue when deal with the site. Two rough ways to collect water is storm drains and perimeter drains. The pipe for water drainage is usually 3-4 inches.
storm drains +sewerage pipe Water flow onto the roof, then is collected in gutters and channeled through down pipes, and finally to ground level. These water flows into storm drain which located around the perimeter of the house
Perimeter drains Perimeter drain is provided around the foundation in order to prevent dampness and flooding building up in foundation walls. Porous bed of gravel Perforated plastic pipe: the perforation in the pipe is located in the bottom so water rising above this level will enter the pipe and drain away from the building
Fabric filter placed around the gravel to prevent particles that may clog the pipes
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Construction phase
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*****************************Construction Phase****************************** THE FOUNDATION ---Footings and Slabs 1. Design foundation criteria and choice Construction of a foundation to transmit the weight of the building into the earth is the next step.
Foundation will settle to suit the soil around and adjust to the loads. Before designing a foundation for the house, an examination of the soil type is needed. According to AS 2870, soil is classified into A, S, M, H, E classes. Generally, many of Melbourne’s land falls into M and S categories.
The foundation I observed is made of site-cast concrete. Most residential foundations are made of either site cast concrete or concrete block. However, site-cast concrete has several advantages over concrete block. 1. Concrete foundation can be made to any dimension, while the block foundation is limited to masonry unit (modules) ---8 inches, in vertical and horizontal dimensions. 2. Concrete foundation will have smooth surface while block is usually made into patterns However, concrete foundation needs more work on site and it doesn’t show advantages in terms of time and cost.
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2. Footings – Waffle Slab The observed house use waffle raft slab which is constructed in a quite different way from stiffened raft and footing slab.
The slab ribs are formed on top of the ground using a grid of polystyrene void forms. These are laid out on a leveled area. The construction is ideally suited to very reactive clay sites
To minimize settlement footings are placed on undisturbed soil. The last inches of soil in the excavation for a footing are often removed with hand tools, because digging machine might make the bearing layer of soil loose. Then, trenches are dug perpendicular to the perimeter of the building's footprint. Steel reinforcement is laid in the trenches to give it a rigid structure. Footings are laid out by the foundation subcontractor, using the same batter boards used by the excavator. Large polystyrene squares are laid between beams (instead of aggregate and sand). Concrete is poured in one process. The sides of the footings are formed with boards staked to the ground. When the concrete are poured into the trench, they will form high pressure pushing outwards to the edge of the board stakes. Formwork must be properly braced so it is strong. It should not flex or move. 26
3. Steps to establish Waffle Slab 1. Ensure building site is level and all plumbing pipes are fixed in place as per plan. 2. Spread a layer of sand or metal dust approximately 50 mm thick over building area and screed level. Place 200Âľm plastic sheeting and tape laps.
3. Set up formwork, set out Waffle Raft Pods in a grid pattern around plumping pipes. Preferred starting point should be clearly stated on engineered drawings. 4. Place reinforcing bars in multispacers positioned between void formers. 5. Place steel mesh on top of Waffle Raft Pods and chair steel mesh at a rate of 4 bar chairs per Waffle Raft Pod. 6. Pour concrete, part fill the ribs to hold the Waffle Raft Pod in position before pouring 85 mm thick slab with 25 mm minimum cover over reinforcing mesh
The major benefits of the Waffle Raft Slab System over conventional slab systems are: -Save time, money and labor -Reduce building cost on site containing, soil, sand and waters -Class S site reduce construction time by 1 day -Less use of concrete as no footings required -Insulation benefits -Design flexibility
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4. Waffle Raft Slab Fact Sheet According to AS 2870 -2011 Residential slabs and footings, waffle raft slab bear minimum design criteria:
-The minimum stem width shall be 110 mm for clad frame -The minimum width of the base of an external beam shall be 110 mm for single-storey articulated masonry veneer and single-storey masonry veneer and 300 mm for two-storey articulated masonry veneer, two-storey masonry veneer -Reinforcement
Square Mesh SL- 82 Trench Mesh 3- L11 TM
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4. Use of Damp Proofing membrane for slab protection
polystyrene squares
Moisture is easy absorbed into concrete by capillary suction through the minute pores and air voids in concrete. Prolonged exposure to moisture can cause slab edge dampness. To protect the footings and slabs, a damp proofing membrane is needed. If damp- proof membrane is not wrapped around the slab, moisture will extrude into footings and slabs.
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5. Deal with Steps in Footings
With strong formworks and steel mesh underneath, waffle slab easily deals with steps. Concrete are poured from lower layer.
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6. Problems solving and issues in real construction The reinforcing helps protect the slabs against cracking that might be caused by concrete shrinkage, temperature stress, concrete loads, frost heave and settlements of ground beneath. As the concrete shrinks, the bonded reinforcement imposes a tensile restraining force. Shown in the picture is how corner reinforcement is used to prevent shrinkage cracks.
One disadvantage of slab is the difficulty of running utilities within them. Once the concrete is established, it is hard to repair and change them. Thus, designers put heating ducts and wiring out of slab. However, there is no way to eliminate under floor plumbing. All pipes that pass through the slab must be isolated from the concrete with fibreglass wrap to prevent abrasion from thermal expansion. The problem shown in this photo is there is a big hole around the pipe in the slab. Concreters might made a mistake by pouring the concrete too close to the pipe. As the inspector came, they realised the problem and cut the concrete around the pipe to give space for pipe movement. The right way to treat pipe in concrete slab is to warp the pipe with fibreglass.
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This is the concrete slab in its curing stage. Curing compensates for the water lost from the concrete due to evaporation. This will ensure concrete attains its maximum hardness. A curing membrane is needed to retain water and minimize evaporation. Cure the concrete at least 3 days and 80% of the hardening will occur in this period. Usually the concrete slab is cured for 7 days. When a new layer of concrete is poured on those concrete which is partially established, cold joints will occur. This phenomenon could be avoided by re- vibrating the concrete to make them as a whole.
Polythene pods are transported on site
Sketch illustrates how a slab on grade is prepared. A 100 mm deep layer of crushed stone is compacted over the subsoil as a drainage layer. Moisture barrier is usually a heavy sheet of polyethylene plastic. Reinforcing helps protect the concrete from shrinkage cracking.
Concrete Slab On Ground with Integral Edge Beam --- Waffle Slab 33
Comparison between concrete slab on ground and strip footing
As in my excursion, the house I found are mainly waffle slabs with concrete slabs on grade. This kind of slab is suitable for clay and flat soil and warm climate zone, as the thermal mass of concrete slab could cool the house. Strip footing is basically continuous reinforce concrete footings that are wider than their depth. Strip footing is more common used in Australia, because it suits wilder range of site conditions.
The main difference between slab of ground and strip footing is where the slab rest.
Polystyrene foam
Polystyrene foam with coating
Slab on grade rest their slab on ground. The concrete is thickened at its perimeter to provide footings under the exterior wall. This kind of construction method is cheaper.
In strip footing, slab is rested directly on footings or on foundation wall which is constructed on concrete footings.
Batt insulation
Both slab types need to be properly insulated. In slab on ground system, insulation is put around the inner side of footing. In strip footing, insulation can be put both inside and outside of the footing.
Strip footing is suspected to retaining wall problem. The pressure from exterior of foundation goes higher when the footing goes deeper. Slab on grade is exempted from this problem for its shallow footing.
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ď ś THE STRUCRAL FRAMING ( Platform Framing)
After the slab is established, structural framing begins. The timber structure constructed nowadays is an advanced version of wood light framing called platform frame. It is an elaborated version of old American balloon style that long studs run all to way from roof to foundation, and floor joists are rest on a recessed area into the studs. The advantage of using platform framing is to use shorter and easier handled timber. And it provides platform on which carpenters can work conveniently. However, this construction method calls for more timer usage in floor area and increase the height of building. This could also lead to large amount of shrinkages in wood, which will make the interior finish surfaces uneven.
Services
Roof Edge Details and roof drainage
Insulation Roof -Roof framing -Roof underlayment, sheathing, insulation and vapour retarder -Roof underlayment and flashing Openings Fenestrations are required in all of planes in structure. Framing members are added around the opening to gain stiffness. Windows and doors each have detailed structural requirement. Sheathing and bracing -Sheathing connect the studs in a single strong unit -rigid sheathing panels and diagonal sheathing boards brace the building against lateral forces. (Floor) wall framing Attach the frame to foundation
Basic components of platform frame structure and construction sequence
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1. Timber Frame Establishment
Bottom plate is bolted to the foundation of the building after the slab is established.
Studs are nailed and established on slab
Studs and bracings are erected with the help of temporary bracings
Sheathing panels and windows are installed.
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450 centre spacing for strip footing 600 centre spacing for sheet footing
2. Floor ( timber floor+ concrete slab)
1800 centre spacing
A sill sealer is needed to reduce air infiltration through the gap. Sill should be made of treated and decayresistant wood. Normally, a single sill meets the need of codes, but doubled sill is used reaching greater stiffness.
TIMBER FLOOR CONSTRUCTION
Normal foundation bolt can hold most building on foundation. For building subjected to high winds and earthquake, reinforcements are needed.
EXPOSE CONCRETE SLAB FLOOR Reason to choose concrete slab floor: Concrete slab is a good thermal mass that absorbs the sun's warmth during the day and radiates warmth into home at night. In summer, thermal mass absorbs heat from the inside air, providing a cooling effect during a hot day.
Attaching the frame to foundation According to AS1684- 2010, the minimum diameter of machine-driven nails shall be 3.05 mm for hardwood and 3.33 mm for softwood framing. No less than two nails shall be provided at each joint. Nominal fixing details are as follows:
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3. Timber frame erection
Picture showing that timber frames are fabricated and assembled lying down on slab before being pushing upwards and erected by worker. TIMBER FRAM CONPONENTS Temporary bracing Bracing
Sheathing panel
Concrete slab floor
Erection sequence: studs + bracing (erect) +temporary bracing+ sheathing panel + window – temporary bracing
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4. Nailing in timer frame wall and spacing Timber brace( contemporary brace) to studs : 2/50 *2.8 mm nails at each joint Lintel to Jamb Stud: 2/75* 3.05 mm dia. nails Nogging joint to stud: not necessary to keep them in straight line. If the wall is to be lined with plasterboard, it's easier to nail the noggings if they are staggered. Stagger no more than 150mm If noggings are to be used for nail fix vertical boarding, it is better to line up the noggings.
AS 1684 bears minimum 2/75*3.05mm nails Multiple Studs: 1/75* 3.05 dia. mm at 600 centres max.(AS 1680-2010)
Plate jointed to stud with 2/100mm nails driven through plate to stud. Nails come into studs with an angle and they lock up the joint when they cross spaces between studs
Bottom plates to concrete slab:1/75 masonry nail( hard driven at slab edge) screw or bolt at 1200mm centre max. stud 45* 90
450-600 centre spacing between studs, depending on roof structures
Noggings: - wall studs should have rows of noggings at 1350 mm maximum centre - noggings are not stress- grades -minimum nogging size shall be minus 25mm by stud size on each side. -minimum cross section 50* 38 unseasoned 42* 35 seasoned 39
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5. Bracing Bracing was traditionally a timber batten let into the face of studs and plates and nailed to them. This method is replaced by using bracing member made out of a perforated metal angle bracing.
no deeper than 20mm
a saw cut made into the face of the studs and plates. The end of bracing member is pushed in and nailing off. NOTE Jamb studs and other load bearing wall bracing is not notched within the middle half of their openings. Roof trusses are not notched. -Maximum size and space of cuts in studs and plates
horizontal span of angle brace: 1800-2700mm
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6. sheathing wall sheathing is an important element in timber framing to resist shear forces. The nails that connect the sheathing panel to framing members have little to do with perpendicular forces against walls, but sheathing panel connect frames into a strong unit. The rectilinear geometry of the parallel framing members has no wracking by lateral forces, but rigid sheathing panels brace the building against these forces. Sheathing also act as a furnish surface for building.
Sheathing panel is always applying besides openings
Polywood sheets
Angle bracing
blocking
External corner junction - three studs are only needed for those corner where weather board or sheet cladding is used. - blocking is needed to avoid the cracks on internal lining that brought by lateral bulking, and twisting of the studs
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7. Timber selection Timber framing construction aims to use scantling timber to build strong wall frames. The timber section being used ranges from 75* 38 to 100*50mm. Large sections are usually used for opening span. MGP grade: a way of express stress grade which related to stiffness. It is an indicator of structural property. Higher value is preferred. STANDARD used for grade: AS 1748
SPECIES
SEASONED: avoid the problems associated with drying and shrinkage which will lead to cracks and distortion in timber
8. window DOUBLE GLAZING WINDOW TYPEhigher thermal benefits FLASHING- controlling water leakage
JAMB STUD- force bearing
WEATHER STRIP- slow down wind penetration INSULATION SILL TRIMMER
Window counts for one of the most important openings when keeping water away from leaking, and the glazing type largely affect the energy efficiency of the building.
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Detailed patterns relate to keeping water away from windows are: WASH, OVERLAP, OVERHANG, DRIP, DRAIN, FLASHING, CAPILLARY BREAK, RAINSCREEN Wash: a slope given to a horizontal surface to drain water away.
Overlap: higher surfaces extend over a lower surface so water move without penetrating into behind structures.
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OVERHANG: a projecting profile above the openings and cracks DRIP: a continuous groove in the underside of the projection
DRAIN AND FLASHING: internal drainage system including spaces and channels that convey water out of building
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CAPILLARY BREAK: stop water from pulling into capillary cracks between elements by enlarging the crack so that water drop would not go through it. RAINSCREEN: prevent water from being pushed through by air In window, we use weatherstrip to slow down the wind
Window Jamb section perspective
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ROOFING AND SIDING Tile is applied to the roof and facilities s is made to gather rainwater from the roof and channel it away from the building. With roofing and siding, the house is ‘tight to the weather’. The project is now half completed. *Truss Roof After timber framings are established, roof framing begins.
Internal walls under trussed roofs Bottom cord
>10 mm
Non-load bearing walls shall be kept a minimum of 10 mm below the underside of the bottom chord, or ceiling battens when used.
Non- load bearing wall Trusses shall be fixed to internal non-load bearing walls as shown below
Framing anchor
Fixing for roof framing
Roof truss to top plate:
Rafters to top plate:
Rafters to top ridge: 1 framing anchor with 3 nails
2/ 75mm skew nails
2/ 75mm skew nails Ceiling joist to rafters: 1/75 hand driven nail or 2/75*3.05 mm machine- driven nail
Ceiling joist to top plates 2/75 skew nails
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ROOFING AND SIDING Tile is applied to the roof and facilities s is made to gather rainwater from the roof and channel it away from the building. With roofing and siding, the house is ‘tight to the weather’. The project is now half completed. -Truss Roof After timber framings are established, roof framing begins.
Internal walls under trussed roofs Bottom cord
>10 mm
Non-load bearing walls shall be kept a minimum of 10 mm below the underside of the bottom chord, or ceiling battens when used.
Non- load bearing wall Trusses shall be fixed to internal non-load bearing walls as shown below
Framing anchor
Fixing for roof framing
Roof truss to top plate: 1 framing anchor with 3 nails
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Supported by internal walls
Conventional Frame Roof
Prop
Overhand- spacing usually 450 or 600 centres.
6000 mm max for sheet roofs 4000 mm max for tile roofs
Reason why prop beam or blocking is needed
Trussed Pitched Roof
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Traditional Roof Construction Sequences and Techniques 1. Before any roofing material is installed, roof sheathing is covered with underlayment. The layer protects water from precipitating into building. 2. Then flashing (metal sheet material) is installed to prevent water leakage at the junctions of roof. 3. Thermal insulation and vapor retardant might be installed 4. Then roof is sheathed with plywood panels
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Traditional Roof Construction Sequences and Techniques 5. Before any roofing material is installed, roof sheathing is covered with underlayment. The layer protects water from precipitating into building. 6. Then flashing (metal sheet material) is installed to prevent water leakage at the junctions of roof. 7. Thermal insulation and vapor retardant might be installed 8. Then roof is sheathed with plywood panels
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Australian conventional Roof Construction
Sarking is generally a layer of moisture proofing paper and it will protect the building from being damaged from water due to roof tiles cracks. Also, sarking can prevent condensation within roof structures flow down into timber. Condensation will form below the roof cover and above sarking. Sharking have a water prove material on its surface, which make it smooth. Sometimes people use sharking as reflective insulation because it has a reflective metallic surface.
Antiponding board is installed between the last filling batten and the fascia board on top of the rafters. This will prevent water that flows down from sharking depositing in eave space.
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Tile installation methods:
fascia
Tile is installed after the roof frames are established. Scaffolder might be used during this phase. Terracotta and cement tiles are particularly suited to Australian climate. Roof tiles cam generally be used on roofs of 15 degrees or more. 17-27 degree are normally used.
Remnants of tile piled on ground. In construction phase, rather than make full use of materials, workers are more likely to break a new tile when they are fitting the roof corner.
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Construction of Roof Edge The edge of the roofing should be positioned and supported properly so that water can drip free of the trim and siding below.  Eaves must be ventilated to allow for the free circulation of air beneath roof sheathing  Gutters and downpipes need to be provided to drain water away Metal drip edge fascia
gutter
Ventilation strip trim
Roof with wood Gutter
Gutters are installed and down pipe holes can be seen along the gutter.
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ď ś UTILITIES AND INSULATION At this stage, the interior utility systems are installed. First the plumbing, then the HAV system, and finally the electrical wiring are installed within the cavities between the studs, joints, and other framing members. After these systems are fastened to the frames, insulation is installed into the studs and ceiling joists to form a thermal envelope around the building. 1. Services - PLUMBING
Thermal insulation around water pipe PVC Sewer pipe Water supply pipe entering the building ( cold water)
Hot water pipe( copper)
Plumping consists of two systems: A supply system and a waste system. Water tape here, water pipe come out from deep ground
Water supply pipe enter are buried deep in the ground before entering the building. This is aim to prevent it from freezing. Supply pipe is usually 2.5mm in diameter. Supply piping need have insulation wrap around them. Waste water pipes are usually larger than water supply system. A vent is need to create a suction to pull the water out.
Solar hot water system Piping of solar heating applications usually installed concurrently with the rough plumbing. Piping is smaller in size
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2. Services- HEATING AND COOLING- Ducting System
Strip bonding the Duct pipe, which might affect the effects of system in long term by folding the pipe. Warm Air Ducting System must be insulated and can be furnace ( air) or boiler ( water) It has the advantages of quick response and cheap installation. However, this system is noisy and makes zoning not possible which is not energy efficiency.
3. Services – ELECTRICAL WIRING
Where switch board will be installed.
Electricity installation should apply AS 3000: 2007. The location of switchboard should near meter box and minimise heavy load area. AS 5601 regulates that gas meter CANT BE within 1M of electricity meter. And no gas flue exists within 500mm of electricity meter.
Electricity Line
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4. Insulation After the services roughly go into the house, insulation should be installed. Thermal insulation helps to keep the house warm in winter and cool in summer by retarding the passage of heat through the exterior surfaces of building. Insulation is an effective way to improve the energy efficiency of a home. Benefits of Insulation include: increased comfort reduced cost of heating and cooling reducing carbon foot-print due to decrease in usage of non-renewable resources and greenhouse gas emissions can eliminate condensation on walls and ceilings Insulation materials can also be used for sound proofing Insulation seeks to decrease rate of transfer of heat through radiation, convection an conduction. This is mainly done in two main ways - Bulk insulation -Reflective insulation.
Reflective foil under laid on batten can also worked as sharking.
Reflective Insulation works by reducing the radiant heat transfer across brick veneer walls by reflecting the radiant. It works most effectively in conjunction with a still air layer (enclosed of at least 25 mm). It should remain clean and dust-free for best performance. Reflective insulation is made of thin sheet of highly reflective aluminium foil laminate.
It is supplied in rolls and typically used as sarking and wall insulation. Reflective foil wrap around the stud wall
Double sided foil is more effective than single side and it is more water resistant. Double sided foil is typically produced with anti-glare coating, which reduces its effectiveness by 10%.
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Bulk insulation traps tiny pockets of still air within its structure. which provide resistance to radiant convective and conducted heat flow. Bulk insulation used by the OB of the house I visited.
Bulk insulation R 5 used within floor slab aiming reaching good soundproofing,
There are types of bulk insulation: Batts and blankets - Natural Wool - Polyester - Glasswool - Rock wool Loose Fill insulation - Paper pulverised fibre - Natural wool - Granulated rockwool Boards - Extruded polystyrene - Foil Faced expanded polystyrene Bulk insulation, particularly denser materials such as rock wool, has good sound absorbing qualities. If soundproofing is desirable, then denser bulk insulation can be installed within internal wall and subfloor.
How Insulation performance is measured Insulation is rated for their performance in restricting heat flow; this is expressed as the R value. Also know as thermal resistance or resistivity. The higher the R value, the greater the insulating effect.
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Reflective foil used here is apparently a sarking which can drain off water that come from the cracks of tiles. This prevents the wood from being rotten. However, scaffolding attached to the eave might damage the insulation layer, which decreases the effectiveness of sarking.
Insulation is penetrated through by services. Cool air will pierce through the crack of insulation.
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5. Brick Work After the insulation is installed around building, bricks need to be laid forming brick veneer wall Brick is used in residential construction due to its benefits, which include:
Bricks bought in site preparing for wall construction
Fire resistance, it is the most resistant to building fire of many masonry unit. Size, a traditional brick is shaped and dimensioned to fit the human hand. Small size also makes them flexible in adapting to small scale geometries and patterns. Cheap and quick construction, suitable to Australian subcontract method of trade and 600 meter square block Low maintenance, relatively cost effective
Large surfaces of materials tend to expand after installation and should be divided into smaller surfaces by regular expansion joints. Expansion joint
Long walls of masonry are subject to expansion as bricks absorb moisture and require expansion joints to relieve pressure. This is usually provided at lines of structural weakness where cracking or crushing tend to occur. As sown in the photo, the wall has an expansion joint besides the opening. This is where cracks often occur. Expansion joint allow the wall respond to moisture movement without causing damage to inner finishing.
Where EXPANSION JOINTS most likely occur:
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Weep holes provide an insurance against damage that can be caused by uncontrolled leakage and expense of rebuilding a wall. It consists of an internal drainage system of space or channels, usually continuous flashing that collects the water by gravity to weep holes direct water back to the outdoors.
In a properly constructed brick veneer wall, a water resistant barrier overlaps the base flashing.
Water that penetrates the brick is prevented from moving further into the wall by wall rope weep.
Base flashing
Expansion joint and weep hole
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Service phase
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After the construction of structures of house, come interior surfaces finishing. ď ś Wall and Floor Finishing
External wall sill to ceiling
Dry wall after the nails and joints have been finished.
Wall and ceiling are finished with plasterboard. Holes are carefully cut when services such as tape is going to penetrate the plasterboard. Basin is fixed, through is not clean. Plasterboard is nailed to fasten to the frame. Dray wall finishing system
10 mm Wet area Boral Plasterboard
The narrow vertical patches are finishing of nails at studs. The horizontal hands are finishing of the long tapered edges of board.
Floor Finishing
Workers use a sticky plaster called joint compound which dries by evaporation. Then a layer of paper reinforce is applied to the finished joint. After overnight drying, another layer of compound is applied, aiming to fill the drying shrinkage of former joint compound. To obtain a smooth surface, three application of joint compound are required.
Then the floor needs to be finished. Many of Australian residential houses just leave the floor as concrete slab for it has good thermal mass. A layer of polished concrete is needed to lay on the concrete slab with a vapour barrier underneath.
Then painter and other textures can be applied on the board.
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Finishing the interior SERVICES 1 – ELECTRICITY, LIGHTING AND COMMUNICATIONS: ‐ Electricity meter, switchboard, power points, on‐site power generation
Meter location is regulated in AS 5601- 2004 -no gas meter within 1000mm if electricity meter
Electricity enters the house through a service entrance and typically pass first through a meter baste that holds the meter to measure power usage. From the meter base, the wires are routed to the main panel, called a panelboard, which then branch out to various appliances through circuit. This is required to be carried out by qualified licensed electricians, due to reasons such as contact with live wires and also the secondary consideration of possibility of fires
Electricity in finish level house Domestic switchboards are installed in the house
Electricity generation, distribution and supply is being deregulated. Private individuals, small companies and large corporation are able to generate electricity and sell it into the distribution grid.
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‐ Lighting The lamp chosen is LED which is really energy efficiency and the light is brighter than other type of light at the same watt.
‐ Heating and cooling The house will use ducting system as heating and cooling, as well as exhaust fans. There is no electricity heating panels installed in house.
‐ Telephone / Internet connections Internet connections are made in study room
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SERVICES 2 –GAS AND WATER SUPPLY -Gas meter and connections (incl. hot water and heating) Hot water heating system is located outside the kitchen. A base is provided under the machine to reduce vibration noise.
For Gas: Materials for piping in gas is copper pipes as regulated in AS 1432-2004
‐ Water fit in Water comes into the site from deep ground to avoid freeze. The pipe is usually 1inche in diameter. Regulation related to pumping and drainage- water services is AS 3500.1: 2003 Sanitary Plumbing and drainage is AS 3500.2: 2003
SERVICES 3 – SEWER AND STORMWATER ‐ Sewer connections, waste water treatment
Sewer pipes are located properly. Water from laundry, kitchen will recycled to grey water tank. These water could be used to water gardens.
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� Stormwater connections, downpipes, rainwater collection
Rain that falls on roof will flow through gutters, pipes and finally is drained out of the building.
Perimeter drainage pipe are located around the foundation of the building to drain off overflow water.
SERVICES 4 – FIXING
Cornice, architrive and butt joint of the door as shown above
Ceiling Architrave Stairs HAC controlling panel
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Rough Interior timber furniture -
Stair Wing door Sliding door
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Appendix
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70
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1
2
3
4
5
6
7
8
9
10
11 12
13 14
15 16
17
18
19
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Temporary facilities Site work excavation Concrete Footings and slabs( waffle) Carpentry Framing of exterior Interior finish Exterior structures insulation Waterproofing Roofing Drywall and plaster Doors and windows Paint Tile Wood flooring Plumbing Electrical HVAC iNSPECTATIONS
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