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A guide for a trouble-free building
October 18, 2019

Tens of thousands of building projects go wrong every year. Most of the trouble starts from a combination of errors and omissions in the plans, a bad relationship with the contractor, mistakes and mismanagement by the contractor and your failure to make sure the building quality is OK.

Building projects should go right. They can be creative, exciting and a financial windfall. The way to do this is to understand the responsibility of each participant. You are the main reason the job will go smoothly.

1. Plan Check

Consumers and builders often assume their drawings are complete and correct. This may not be the case even when dealing with architects and experienced designers. The drawings may look great, but are they right? Remember the builder will build what is on the plans.

Detecting problems on the plans before any work commences will save you money, time and the nightmare of a dispute with the builder.

A careful PlanCheck will help you:

  • identify mistakes and omissions before obtaining quotes
  • help minimise confusion and expensive variations.

For instance, the builder may use inferior paint unless the quality is specified in the documents.

You can do most of this yourself with the following checklist. With complex projects, it may be necessary to get a professional to do the PlanCheck for you.

1.1 Getting Started (before construction begins)

Issue Assess/check Recommendations/review
Condition of
adjoining structures
  • adjacent structures especially on adjoining boundaries
fences, screens, walls
  • retaining walls especially on or near boundaries
kerb, gutter, footpath, verge
  • road surfaces
  • service access, grates, cover
  • a photographic record may be required
dilapidation reports may be required
engineer’s opinions required
annex records/reports to contract
  • copy record to affected parties e.g. neighbours, council, supply authority
  • protection to be provided by the contractor
  • highlight items to be protected
Damage to public
  • sewer access, vent
  • water
  • gas
  • electrical poles, wires
  • contractor to locate all services
drainage diagram provided
  • identification survey provided
  • client indemnity against any damage
protection to be provided by the contractor?
Site considerations
  • aspect mainly; north/ south/east/west
orientation of building
views, outlook, privacy
  • exposure
  • slope and drainage
  • overshadowing/privacy
  • by adjacent property
by proposed structure
  • surface run off from adjoining properties
  • access to sunlight – shading/protection
north-south breezes – also see amenity
  • N/NE to N/NW aspect for living areas
best use of – affectation by others
durability/design to terrain category
  • relocate shaded areas, openings
review building envelope
arrange pre-approval meeting with Council or certifying authority
Adverse influences
  • trees affecting structure/services
  • soil stability, e.g. reactive soils
  • erosion control
termite colonies/activity
  • access
excavation in rock
  • bad or filled ground
ground water/water table
  • contamination – asbestos, lead, fuels, poisons, other pollutants
  • obtain an opinion of arborist/tree surgeon
  • clarify council removal policy
  • obtain an opinion of geotechnical engineer (see council soil maps)
  • obtain indicative rates for retaining walls/drainage
  • risk assessment trees/stumps/roots/debris
  • PC to locate, destroy & monitor colony
contractor to include temporary access
safe manoeuvrability – ingress-egress
permanent access costs and site security
  • obtain indicative rates for rock excavation, de-watering, pier & beam construction, back-filling, compaction
  • obtain indicative rates for removal of contaminants – EPA approvals
Condition of any
existing structures
Identify, seek further advice about:

  • structure
  • concealed damage – termite
re-use of materials – roof tiles, windows, gutter, etc.
  • services – electrical, sewer, water, air handling, lift, fire services
trees and vegetation
Check or obtain:

  • original drawings/specifications
  • pre-purchase reports
timber pest reports
pre-construction report
  • engineering details/reports
  • other specialist advice
clarify the protection of trees/vegetation
Consultants you need
  • Surveyor
Building designer/architect
  • Structural engineer including:
  • Geotechnical advice
  • Hydraulic engineer
Electrical engineer
  • Mechanical engineer
  • site and contour survey
drawings including shadow diagrams
  • Council D/A and construction certificate
heritage impact statement
  • soil classification
  • structural drawings
for complex drainage systems
for larger installations
for complicated air conditioning
  • check conditions of consent
Fees and costs
  • Council D/A
  • Construction certificate
Consultants costs
  • Sydney Water
Fee rebates/refunds
  • Select either local Council or accredited private certifier
  • If any doubt clarify onus for costs and fees
  • Payable by who?

1.2 Approvals

When you want building work done you need to obtain Development Approval, Construction Certificate and Compliance Certificates from either your local council or an accredited certifying authority. Your local Council does not take responsibility for their approvals, whereas an accredited certifier may (under legislation) be liable for their work.

1.3 Dimensions that work

Why not check your room sizes and other important measurements

 Item/area Acceptable
min .dimension
Generally Check circulation, flow, linkages between spaces
BCA sets out the required ceiling heights
width length height
Hall 1m 2.43m
Living areas 3.6m 4.2m 2.43m
Dining room
2.7m 3m 2.43m
Bedroom 2.7m 3m 2.43m 3.0m preferred minimum
Main bedroom 3.6m 3.3m 2.43m
WC 1.05m 1.6m 2.43m 2m with inward opening door
Bathroom 2.1m 2.4m 2.43m
Ensuite 1.2m 2.1m 2.43m
Kitchen 2.4m 2.4m 2.43m
Laundries 1.6m 1.35m 2.2 1.8m length preferred
Balconies 2.4m 3m
Stairs 0.9m
1m preferred
2m Riser 165 -170mm preferred -190mm max.
Tread width including nosing 275 – 290mm.
Avoid winders, single or double steps.
Non-slip surfaces/nosing.
Robes & cup’s
600mm 800mm in laundry

linen 450mm

pantry 450mm
hanging rods 1.65m
from floor
worktops 600mm 600mm
Oven/grill height to suit the appliance
eating 350mm 450mm 760mm
fridge 700mm 450mm 1.65m Allow for ventilation
microwave 600mm 450mm 400mm Check exact appliance size
Laundry fixtures
wash machine(WM) 700mm 700mm
Can WM be installed without removing tub?
dryer 600mm 600mm Can WM lid open under the dryer?
 height to suit top of the dryer – minimum 2.2m
bath 750mm 1500mm 450mm to suit wall tile courses.
vanity top 600mm 810mm WCs minimum 400mm from sidewall
shower 900mm 900mm
Windows Centre of rooms, best use of view, margin over for curtains/blinds.
Glass specified – safety, obscure, double
Sills over
WC/tub 1.2m To suit bed, desk, etc.
Water bars to door thresholds – outward opening external doors.
bedroom 0.9m
kitchen 1m
Doors Check openings do not unduly affect room use.
Locate to allow robe/cupboard.
Clearance under to suit floor covering. Safety glass allowed.
generally 800mm
bathroom 700mm
entry 900mm
Hardware, switch heights
GPOs (power points)
1050mm above floor Switches and door furniture at the same height,
deadlock security to windows and doors.
Locate GPO’s above the skirting and to suit equipment.
Lights Centre of rooms (allow for built-ins)
75mm clear space all round tap head.
Shower and bath taps easily accessible.
Balustrades 1m Childproof, max 125mm opening, over drops > 600mm.
Check material durability
Single garage 3m 5.5m 2.1m 6m preferred, 6.6m if workbench required.
Double garage 6m 5.5m 2.1m Check height doesn’t limit the choice of a garage door.
Windows may limit wall storage – skylights preferred
Eaves overhangs 450mm 600mm on the north side – 900mm preferred if glazing to floor

1.4 Amenity and services

Issue Item/location/type Recommendation/check Notes
Natural light
  • dressing room
  • ensuite
  • WC
  • bathroom
  • hallway
  • 10% of the floor area
  • skylights/sky-tubes advised
glass blocks
  • internal rooms
laundry kitchen
rooms with showers
  • windows as shown
  • 5% of the floor area
north-south flow
  • recirculating
  • delayed switch off
  • connected to light
check size, opening hand, type
  • external doors
  • deadlocks
  • alarm system
privacy latches
Check the type of overhead door automatic equipment.
  • rangehood
  • security
garage door
  • TV antenna
exterior lights
  • GPOs switch lights
  • date cable smart wiring
hose cocks
  • roof and site drainage system
gas reticulation
  • hot water
  • interior & exterior
number & location – two-way for halls
  • front – rear – balcony
DPs, sumps, drains shown
    • Consider rainwater tank storage
    • Retention pit required
number gas bayonets
type, size
  • gas – solar – electrical
Check type, capacity and warranties of any mechanical equipment; e.g. who has arrived at AC capacity.

Location close to fixtures

Tray and drain (if interior)

Pipework insulated

Thermal performance
  • sarking to roof
  • ceiling insulation
  • sarking/insulation to walls
  • roof void ventilation
  • air conditioning, room heating
underfloor heating
  • heavy duty – hail proof
  • R3 roof R2 walls and ceilings
  • wall insulation to be breathable
affect of roof glazing
  • affect of large glass areas/aspect
thicker or double glazing to windows
  • turbo/gable
compliance with codes
running costs of heating
Confirm NATHURS rating required by council
  • noise between occupancies
noise between sleeping-living
  • noise from external sources
  • noise from services
  • insulate interior walls between
thicker or double glazing to windows
relocate or isolate service equipment

1.5 External materials and finishes

You will eventually need to chose what you want so why not do it now. We have found that is important to choose durable weather-exposed, materials and finishes.

Issue Assess/check Recommendation/review Notes
  • ownership of salvaged materials
  • disposal costs including tip fees
  • weather protection
  • security of uncovered structures
  • clarify any possible misunderstandings
have you considered selling the existing building for relocation to another site?
  • bond and joint finish
  • surface finish
joint colour
sill type – a minimum of 15 degree slope
control joints – 9m max
  • moist masonry to garage, retaining walls, below DPC – salt
  • wall/frame ties
weep holes
  • check exposure class of bricks
raked – flush – struck – ironed
  • face – bagged – render
is colour contamination likely; e.g. dark mortar on light brick
  • identify the location of control joints
  • conceal if possible behind downpipes
  • will the area be used for storage?
  • avoid coatings to damp brickwork 
is cavity brick a good option?
  • stainless steel – plastic
Especially for below damp-course, in-ground contact, coastal location, around the swimming pool
  • any low pitched areas
  • type of flashing specified
  • sarking/insulation
  • check profile suitable for pitch
  • warn of increased risk
check for dissimilar metals
paint coatings should not replace flashing
check thermal performance of roof
  • weatherboard
  • type/manufacturer specified
  • pre-finish or paint
finish colour specified
check thermal/acoustic performance
  • sash type and hand
material/finish specified
distance from coastline
  • weather protection
check the direction of sash movement
  • fly screens included?
  • deadlocks included?
  • obscure glass to bathroom/ensuite/laundry
  • timber – exterior
  • thresholds
  • solid core preferred/minimum hinges
Did frame rebate from solid piece?
water bar to thresholds
  • check durability of finish
  • s
top & bottom of the door painted
high rise where weather-exposed
  • sub-sill
Steel elements
  • durability of lintels, brackets, ties, handrails, post bases
surface finishes to exposed structural steel
  • hot dipped galvanised at minimum
  • stainless steel in marine locations and all fixings
specify paint system if not galvanised
  • fencing
  • pergolas, awnings‚
retaining wall type/height
plantings and vegetation
  • material durability
treated timbers preferred
  • fully galvanised fittings – stainless steel preferred
  • engineer required/durability
check size, shading, root type
  • avoid planting trees close to buildings, paving, fencing

1.6 Internal materials and finishes

You will eventually need to choose what you want – so why not do it now.

Issue Assess/check Recommendation/review Notes
  • particleboard floor
timber floors
ventilation under
  • rough sand of joints included
  • consider any requirement for future polished floors
  • species and grade identified
  • expansion joints
clear of walls
type of finish specified
  • wall vents @ 1 metre
Floor and wall tiles
  • walls – floors – fittings
expansion/control joints
  • floor wastes & falls in floors
  • hob – waterproofing advantage versus access obstruction
  • check wall heights
  • detail any pattern work
detail location of all fittings
specify grout colours
  • anti-fungal grouts
  • show floor drainage on plan
Also, see PCs
Bathrooms and ensuites
  • vanity cabinet
  • shower screen
  • width – water resistant
  • acrylic
  • enamel
  • swinging
  • frame less
Also, see PCs
  • basin included
mechanical ventilation
  • widen WC to 1050mm
door opening outwards
  • chute provided from 1st floor
  • storage cupboard
  • broom storage
  • ironing station
  • exhaust for clothes dryer
  • wall mounted cupboards
pantry storage
under bench storage
  • location of the fridge, oven
exhaust fan
door swings of DW, oven, fridge to adjacent cupboards
  • fully lined
  • corner use
microwave shelf
  • pull out drawers
  • vented to exterior
  • 180-degree bull-nose edge
  • integral splashback 100mm high
Also, see PCs
  • wardrobe size
  • satisfactory wall space
  • check GPO location
  • cloak cupboard
  • hanging space in cupboard
  • protect door from weather
  • swinging or sliding doors
  • height of shelving/rails
  • robe details in documents
hanging rails included
  • mirror doors identified
  • skirting mould/size specified
architrave mould/size specified
  • timber species specified
  • reject MDF in wet areas
  • useful cupboard under
  • lining?

1.7 Trouble spots

These are the areas that commonly cause problems that can be very expensive to fix later.

Issue Assess/check Recommendation/review Notes
  • adequacy of ventilation and light
  • detail & location of drainage
type of waterproofing
termite protection measures
retention of soil embankments
  • access to or cleaning of drainage
  • check waterproofing warranties
check termite warranties (3660.1)
  • soil level below floor level
  • use moisture/termite/rot-resistant materials
Provide detail drawing
  • any low pitched areas
  • complex details
geometry e.g. octagons, curve. splays
    • concealed gutters e.g. box
changes in pitch (flashing)
penetrations e.g. skylights, dormer windows
weather exposure
  • check profile suitable for pitch
  • identify areas needing special care
manufacturer warranty
  • no reliance on sealants
  • durable, adequate size, overflows, access for cleaning
  • adequate downpipes
anti-ponding board under sarking
Warn of increased risk of water penetration
Roof glazing
  • pre-made units
proprietary systems
  • use systems that are purpose made for roof installation
  • avoid timber-framed on site
Slab on ground
  • engineer
  • engineer to inspect and certify design, placement (vibration) and curing including
    • piers
    • drop beams
all slab
  • termite protection
    • split levels
building on boundaries
slabs on ground
construction joints
    • clearance / access
  • clarify method and ongoing maintenance costs, warranties and compliance with 3660.1
low risk methods – slab edge exposure, steel or treated timber frame
  • minimum 400mm below floor frame
  • detail the inaccessible entry points
  • balconies above habitable rooms
basements including ground levels above internal floor levels
  • wall cavity drainage above habitable rooms
membrane roofs
  • rooftop terraces
  • planters
  • bathrooms, ensuites, laundries
  • step down from the interior
  • membrane specified – 2 layer sheet membrane preferred
expansion joints detailed in large areas of tiles including perimeters
drainage outlets specified
  • emergency overflows specified minimum 38mm
  • upturn for hob-less shower
  • provide detailed drawing
  • DFT preferred
Include a list of all documents including engineering drawings, schedule of finishes
  • Agree completion date
  • Request retention
Agree liquidated damages (weekly payment for any time overrun)
  • Agree schedule of progress payments
  • Review all insurance – obtain certificates of currency for:
    • home building warranty
    • worker’s compensation
public liability.
Understand the process required to vary costs, materials, design or time for completion.
  • Describe the stage that must be reached for each progress payment

1.8 Price check

It is your responsibility if you knowingly accept a price for that work that is too low for the quality and complexity set out in the documents.

It is always best to reality test the price by asking:

  • is the price significantly lower than the other price or prices?
  • is the price per m2 close to the usual cost for this standard of work?
  • does the price include expensive items such as complex shapes or roofs?
  • are there likely additional extra costs such as limited access, extensive excavation?

Likely cost per square metre

Architect designed One off buildings Project and package
Basic quality $1,500 $1,100 $700
Above average $2,000 $1,400 $900
Premium quality $2,500+ $1,800 $1,400

The contractor‘s quotation will include estimates of the costs of items that require your personal selection. Once you have selected your fixtures, appliances and accessories, you can either supply these yourself or the contractor can purchase them and reconcile any cost differences. If you know what you want, you will know exactly what the cost will be for each item. Preferably, request the contractor to supply and fix all items or clarify who will otherwise be responsible for delivery, insurance and faults in any item you provide.

Item $ advised Item $ advised
kitchen cupboards $ built-in robes – B1/B2/B3 $
sink $ linen $
dishwasher $ cloak $
hotplates $ doors $
oven/wall oven $ door hardware $
range hood $ light fittings $
microwave $ carpet floor covering $
exhaust fans

  • WC/kit/bath/ensuite
$ vinyl floor covering $
wall tiles

  • laundry
  • kitchen
  • bath
  • ensuite
  • WC
$ laundry tub & cabinet $
floor tiles

  • laundry
  • kitchen
$ dryer $

  • ensuite/WC
$ washing machine $
thresholds & sills $ hot water service $
vanity basin

  • bathroom/ensuite/WC
$ air conditioning $
vanity cabinet

  • bathroom/ensuite/WC
$ heating & cooling $

  • WC
$ underfloor heating $

  • ensuite
$ security/intercom $
spa including motor

  • bathroom/ensuite
$ garage door equipment $
toilet suite

  • bathroom/ensuite/WC
$ auto entry gates $
shower screen (S&F)

  • bath
  • ensuite/WC
$ entry door $
wall cabinet

  • bath
  • ensuite/WC
$ entry door hardware $
towel rails

  • heated towel rails
$ security doors – front/ back $

  • ensuite/WC
$ skylights $
soap holder $ TV aerial & circuitry $

  • ensuite/WC
$ fencing and gates $

  • bathroom/ensuite/WC
$ clothes line $

  • laundry
  • kitchen
  • bathroom
  • ensuite/WC
$ paving $

1.9 Provisional allowances

The contractor usually includes estimates for parts of the work that can’t be costed because of incomplete information or unknown factors. Common provisional allowances include service connections, excavation, foundations, removing or importing fill.

Item Allowance Notes
Sewer drainage and connection
Water service
Electrical connection
Importing fill
Exporting fill including tip fees
Rock excavation
Retaining walls

2. Selection of Contractor

Like any good relationship, a successful building partnership starts with a careful choice of partner. There are many ways to find the right builder:

  • word of mouth
    • friends and relatives whose judgement you trust
    • professionals, such as architects, engineers, tradesman and suppliers
  • previous contractors you have liked working with
  • building associations
  • names from local jobs that you like the look of.

Once you’ve got some contractor names, why not check them out carefully:
ring their last 3 clients and ask:

  • was the contractor good to deal with
    • did the project finish on time and budget
    • were you satisfied with the quality
    • how did the contractor handle the inevitable problems
    • was the contractor a good communicator
  • talk to the contractor about your job:
    • Is the contractor interested?
    • Does the contractor ask lots of questions?
    • Do you like the contractor?
    • Has the contractor done lots of similar jobs?
    • How can the contractor demonstrate to you they are right for your job?
  • get down to detail:
    • is the contractor licenced?
    • can the contractor provide insurance?
      • home building warranty insurance
      • public liability
      • worker’s compensation
      • all risk

3. Progress Inspections

You need to know the builder is complying with all the regulations and that the quality of his work is acceptable.

Even the best builders make mistakes. Their subcontractors may take short cuts. Supervision on most jobs is minimal and rarely looks in all the
hard to get to places such as the roof interior, under the floors and those flashing up on the roof.

Councils DO NOT take responsibility for the quality of the work and are often not called at the important times.

You need reliable independent advice at the key stages:

Inspection Who should inspect
Footings The engineer who designed the footings or slab
Frame (just before plasterboard linings are fixed, after all services and waterproofing is complete) Building consultant
Final (when everything is finished) Building consultant

4. Certification

You can ask the contractor to give you certain certificates when the job is finished. The contractor will get these from his subcontractors, suppliers or the engineer.

The certificates help verify the quality of the work to you and future buyers. If anything goes wrong with the work that was certified you will know who is responsible. This certification is like a pedigree or bona fide that everything is OK.

The typical certificates you might get on a residential building are:

  • Termite protection including a plan of the areas protected
  • Plumbing final certificate
  • Certificate of compliance for gas installation
  • Waterproofing certificates for the showers, bathrooms, laundry and balconies/planters above habitable rooms
  • Glazing certificate
  • Engineering certification of:
    • piers, footings, concrete slabs, any non-standard beams, retaining walls and pools
    • complex drainage systems
    • roof trusses and frames from the truss manufacturer
  • Surveyor’s certificate proving the location of building in accordance with approved plans and a maximum height of the building (if required by Council)
  • Proof of final inspection*
  • Certificate of occupancy*.

* These certificates may be obtained from Council or an accredited private certifier.

There may be warranties of equipment and appliances such as:

  • wall ovens and hot plates
  • hot water heater
  • spa equipment
  • automatic garage door
  • pool equipment heating or air conditioning equipment
  • security and intercom systems built-in vacuum equipment
  • proprietary products such as pergolas, roof glazing systems, awnings
Talk to the experts
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