Assessment of Residential Building Design and Construction Report

This report provides a comprehensive evaluation of a residential building's design and construction, focusing on compliance with the Building Code of Australia (BCA) and related Australian standards. The report begins with an introduction, outlining the scope, objectives, and building description, including its classification as a Class 1a ground-oriented residential building. It then assesses the building's location in a bushfire-prone area and discusses alternative design solutions to minimize bushfire risks, including site clearance, house design modifications, and material selection. The report identifies design and site management issues and presents an assessment of the building using the BCA, highlighting non-compliance issues such as the absence of fire escape signs, smoke detectors, and fire-rated doors. The report also includes structural analysis, covering tie-down connection design for wind uplift and shear forces, and the influence of tile cladding on the dwelling's structural design. Furthermore, the report addresses fire safety and bushfire considerations, proposing a setback for the wall on the southern boundary and providing a smoke alarm location floor plan. The report concludes with a BAL 19 zone location proposal assessment, ensuring the building meets the required standards for bushfire protection.

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CONSTRUCTION MANAGEMENT/BUILDING SURVEYING
by [Name]
Course
Professor’s Name
Institution
Location of Institution
Date

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1.0 Introduction
1.1 Development and Scope of the Report
Anyone working in the building and construction industry is subjected to guidelines and
standards to be followed for safe and successful completion of construction projects. Also, they
should be relevant to certification schemes and other information within the building industry for
efficient delivery of services.
The objective of this report is to give an evaluation of the design and construction of a
residential building in accordance with the Building Code of Australia (BCA) and Related
Australian standards. The current BCA has an approximate 160 Australian and International
Standards (ABCB, 2018). The analysis of the building under evaluation wills the limited to the
BCA standards. Therefore, the scope of the report covers all standards and guidelines contained
in BCA as pertains to new homes and renovation of homes, building contracts, building
inspections, building tolerance, energy efficiency building products, building design standards,
etc.
1.2 Building Description and Type
The building in plan and under evaluation is a residential building. The building is
regarded as a residential building because more than half of its floor space is used for dwelling
purposes. Otherwise, the building would be regarded as a non-residential house. According to
type, the building is categorized as a ground-oriented residential building, i.e, the dwelling has an
entrance directly from the ground surface.
A further evaluation of the building shows that the building can be classified to be in
Class 1, and precisely Class 1a according to the Building Code of Australia (BCA). The BCA
states a Class 1a building to be “A single dwelling being a detached house, or one or more

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attached dwellings, each being a building, separated by a fire-resisting wall, including a row
house, terrace house, town house or villa unit” (QUEENSLAND BUILDING AND
CONSTRUCTION COMMISSION, 2018). The building evaluated is a single dwelling residence
comprising of 3 bedroom units, the kitchen, dining, study rooms, garage and other common
essential units of a residential house.
Different materials are used for the construction of the various parts of the building. The
roof was constructed using metal roof sheeting on timber framings with an aluminum cover
panel, folded finish/color to match window frames. The walls are constructed using timber
battens mounted over timber studs – a lightweight cladding is put on the timber. The building
floor is made of a concrete slab on a compacted fill and footings. The floor extends to a timber
deck and it is insulated under the slab. A WP membrane and compacted sand to the BCA are put
beneath the slab. Other building components such as doors and windows are made of timber and
metal frames with fitted glass as per BCA.
1.3 Site Criteria Used to Asses the Building
The criterion used to assess the building is bushfire zone. A general view of the building
site shows that the structure is built at a bushfire prone area. A bushfire prone area is an area
which is subject to or likely subjected to bushfires. The building is located close to trees and
bushes, increasing chances of the building being exposed to fires in case they occur in the nearby
bushes. BCA outlines specific bushfire construction guidelines for some particular residential
buildings in “designated bush fire prone areas” objectively to minimize the ignition risk from a
bushfire. As stated before, the building is under is classified as Class 1a, and the BCA bush fire
construction requirements are inclusive of these class.

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Following the Australian Standard AS 3959 – Construction of buildings in bushfr-prone
areas (2009, incorporating Amendments Nos 1, 2, and 3), the building can further be categorized
according to the Bush fire Attack Level (BAL) to be BAL-19 – Moderate risk. The classification
is based on the assessment of the building site – there is moderate to medium vegetation cover,
an indication of the building being in a fire prone area.
2.0 Alternative Design Solutions
2.1 Alternative Designs
According to Archicenter Australia, the risk to property and lives during a bushfire can
be reduced through architectural design principles (Hordov, 2018). Alternative designs for the
building to minimize bushfire risk are not but limited to siting, house design, construction
materials, and landscaping. Therefore, alternative design of the building will begin by a
clearance of the vegetation around the building. The building will also need to be kept away
from steep hillsides and ensuring there is enough cleared land between the house and the bushes
around. As far as the house design is concerned, the roof could be improved to be simpler with
uncomplicated layouts, window protection, and in-built water storage facilities. The house design
could also incorporate fire resistant materials and an installation of sprinkler systems (Lataille,
2002). Alternative design will also include various materials for various parts of the building.
The timber section of the floor should be sheeted underneath using a non-flammable material;
the construction can be done using a fire-retardant treated timber. The walls, windows, doors and
general ceiling and roofing material would be non-combustible. Lastly, as a part of alternative
design, landscaping could be done by planting tree species classified as bushfire-resistant; they
can also be used as wind breaks and barriers.
2.2 Design and Site Management Issues

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Issues pertaining to design and management are likely to occur when information is
missing, there is poor communication, the project/building documentation are inconsistence,
resource allocation is not of standard, poor decision making, and a lack of adequate information.
With the current growth of technicality in buildings, design and management issues have become
more prevalent. Also, contributing to this is the increase in the range of products and materials,
increased strictness in standards and regulations, and an increase in the number of professionals
in the field.
Handling of design and site management issues can be done through in a number of ways
including, client engagement and control, proper organization, collaborative project execution,
laying out design management plans, and proper allocation of duties.
3.0 Building Assessment Using BCA
3.1 Assessment Using BCA
The table below is a summary of the identified issues of non-compliance:
Item BCA Clause Non-Compliance Issue
1 D2.23 There are no signs to show fire escape
routes
2 Caluse 4 of Specification E2.2a of
BCA2010 and AS1670. 1-2004
There is no smoke detection devices in the
building
3 NSW H101.16 of BCA2010 There are no self closing -60/30 fire doors to
the garage.
4 C1.10a of BCA2010 The wall material do not satisfy fire hazard
properties
5 C3.15 of BCA2010 There are mechanical ducts in the building

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with no fire dampers.
6 C2.6 Windows are too close to the floor.
7 D1.2 There are no enough exists to enable safe
egress in case of an emergency
8 F4.5 There is no visible ventilation for the
building.
List of Requirements
1. Signage should be provided to show appropriate ways for exit in case of emergencies
such as fire.
2. Installation of smoke detection devices in the building.
3. Self closing -/60/30 doors.
4. Use building material for walls that are fire resistance.
5. Fire dampers for mechanical elements in the building with no installed fire dampers.
6. Renovate windows to 600mm and above, above the floor.
7. Install extra exists for easy escape in case of an emergency.
8. Provide ventilation (adequate) (Australian Building Codes Board, 2015;
SA.GOV.AU, 2018).
Part 1: Structure
Question 1.1 Framing
1.2.1 Tie Down Connection Design
1. Specific tie-down required:

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AS1684.3 p161Table 9.2 (uplift), Table 9.3 (shear) For wind classification C2 and N2
wind speed area.
 Specific connection required for uplift forces.
 Specific connections required for shear forces From tables.
AS1684.3 Clause 9.5 Table 9.4
 Nominal fixings required.
Specific tie-down requirements:
 Between rafters and garage wall top plate
 Standard trusses to top plates and floor frames
 Frames on floors to footings.
Specific tie-down requirements:
Area held down = Spacing x Tie – down spacing
2. Wind uplift area:
Assume rafter spacing/batten spacing = 0.9m,
Therefore, Wind uplift area = 0.9 x 0.9
= 0.81m2
3. Uplift Pressure:
AS 1684.3 Table 9.5 – Net Uplift Pressure, kPa: for battens to rafters/trusses general area/1200
mm of edges, Wind Classification C2, Sheet Claadding;
= 5.50kPa
4. Wind uplift load:
Within 1200mm centres;

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Net uplift Force = Wind Uplift Area x Net uplift pressure
= 0.81 x 5.5
= 4.46.
5. Joint Group
AS1684.3, Selected joint group = JD4 (truss specification)
6. Sutable tie-down connection
AS1684.3, Table 9.25
For 1200 centres and the tie downs are also at 1200 centres,
Uplift capacity = 4.46 kN
Adopt – 1/75mm long, No. 14 Type 17 screw.
7. Shear forces for joists and bearers:
Shear connection at floor frame, projected height:
= (8910/2 x tan 25 + 150)(roof height) + 2400 (wall height) +
(floor frame allowance 200)
= 4.79 m
For 450mm and 2400mm joists and bearers, shear forces are:
Joists =4.79 x 0.95 = 4.55
Bearers = 4.79 x 5.0 = 24kN
(Forest & Wood Products Australia, 2010)
1.2.2 Influence of Tile Cladding on Dwelling Structural Design.
Cladding forms the non-structural components, external surfaces of the building.
However, cladding plays a critical role to a structure’s stability in as much as it is attached to the

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building. Primarily, cladding play the structural role of transmission of wind loads, snow loads,
impact loads and their own weight to the framework of the structure (Reid, 2000).
All roofs cladding basically have the same function. However, because of their properties
such as insulation and weight, a change in the cladding can have significant structural effects on
the building structure. A change from sheet cladding to tile cladding by the client, therefore,
means an influence on the building structure. Ideally, roof tiles are used to provide protection
from weather to other building parts such as the walls; also, in some cases for aesthetic beauty.
In this case, tiles will protect the building components from harsh weather and other external
factors that might compromise the building stability. Other than structural advantages of tiles,
they will add weight on the building structure as imposed/dead loads. If these loads were not
fully accounted for, they may result to some extent of structural failure on the building.
Part 2: Form.
2.1 (a) Fire Safety and Bushfire
2.1 (a) (i) Proposal for Setback of the Wall to Southern Boundary Assessment
According to the BCA P3.7.1.8 provision, “fire separating walls between Class 1
buildings must have a continuous fire resistant level (FRL) of not less than 60/60/60 (grading
rate in minutes for structural adequacy/integrity/insulation)” and “must commence at the footings
extending to the underside of a non-combustible roof covering across voids in roof spaces
between residences and over eaves and verandahs” (abis, 2018). A setback of the wall on the
southern boundary of 800mm satisfies these requirements. BCA also requires that a fire
separating wall to extend 450mm above any combustible material. This wall is 800mm. The
proposal complies with BCA. Additional information that might be required to assess full

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compliance includes sealing specifications, timber penetration parameters, and gap sizes between
the wall and underside of the roof.
2.1(a) (ii)Smoke Alarm Location Floor Plan.
Design Reasoning
Four smoke alarms are proposed for the building. The smoke alarms are proposed to be
located at the kitchen area, next to the garage, at the study adjacent to the kitchen, and at the
general area within the living room and dining room. The smoke alarm located at the kitchen is
put there because this is place with is most vulnerable to fires, and where smoke is likely to
originate. The other alarms on the rear side of the building are located there because they are the
closest to the surrounding bush areas. In case of a bush fire, they are the first to detect the smoke.
One smoke alarm is located at the dining/living room area for general purposes; just in case there
is a fire that might necessarily originate from the kitchen area or the bushes (Bunker & Roux,
2006).
2 (b) (iii) BAL 19 Zone Location Proposal Assessment
The building meets some of the requirements for bushfire safety according to BCA 309A.
An assessment of the building shows there are evidence of static water supply and a likelihood of

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access to emergency vehicles. The building also demonstrates compliance with BCA
Performance Requirements G5.1 (in BCA Volume 1) and P2.3.4 (BCA Volume 2) i.e., there are
prescriptive solutions and performance solutions – Australian Standard AS 3959, and National
Association of Steel Housing (NASH) Standard. Except for the non-compliance requirements
detailed in section Task 3, the building’s location, materials for construction, and all a majority
of the structural elements satisfy Clause 3.8 of AS 3959 – “Where any material, element of
construction or system satisfies the test criteria of either AS 1530.8.1 for BAL-12.5, BAL-19,
BAL 29 and BAL-40 or AS 1530.8.2 for BAL-FZ, it satisfies the requirements of that BAL”
(STANDARDS AUSTRALIA, 2009).
2.2 (a) Health and Amenity
Clause F1.7 – Water proofing of wet areas – All the parts of the building the need water
proofing have been installed with appropriate material. The baths and washrooms are paved with
bath tiles, while the laundry area is paved with laund tiles.
The bathroom and laundry floors are at a level above the occupancy units to permit
drainage. The building meets the BCA requirement Clause F1.11 – Provision of floor wastes.
The residential building has been provided with kitchen sinks and facilities for food
preparation, washrooms, washbasins, and laundry for washing clothes. The dwelling complies
with BCA requirement, clause F2.1 – Facilities in residential buildings.
Further assessment of the building shows that there are a few requirements that need to
be made to comply with BCA. Clause F4.5 Ventilation of rooms: There are no mechanisms for
natural ventilation; neither is there mechanical ventilation or air-conditioning systems. In
addition, BCA requirement Clause F4.12 – Kitchen local exhaust ventilation has not been met.

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The aforementioned details are required to render the proposal BCA respective Clauses
Compliant (Australian Building Codes Board, 2013)
References
ABCB. (2018). National Construction Code. Retrieved May 30, 2018, from NATIONAL
CONSTRUCTION CODE: https://www.abcb.gov.au/ncc-online/About
abis. (2018). Building and Pest Inspections Brisbane: ABIS | Australian Building Inspection
Services . Retrieved May 30, 2018, from abis: https://www.abis.com.au/
Australian Building Codes Board. (2013). Class 1 to class 10 buildings: Volume 2 of National
Construction Code, Australian Building Codes Board. ABCB, 2013.
Australian Building Codes Board. (2015). NCC...Building Code of Australia. ABCB, 2015.
Bunker, M. W., & Roux, R. J. (2006). NFPA Pocket Guide to Fire Alarm System Installation.
Jones and Bartlett.
Forest & Wood Products Australia. (2010). AS 1684 2010 Education Resource Package:
Residential Timber-Framed Construction : Parts 2 & 3. Forest & Wood Products
Australia.
Hordov, N. (2018). How to best design your new home to minimise bushfire risk. Retrieved May
30, 2018, from Reporter Community: https://www.communitynews.com.au/eastern-
reporter/real-estate/how-to-best-design-your-new-home-to-minimise-bushfire-risk/
Lataille, J. (2002). Fire protection engineering in building design. Elsevier.

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QUEENSLAND BUILDING AND CONSTRUCTION COMMISSION. (2018). Calssfication
summary of buildings and structures. Retrieved May 30, 2018, from QUEENSLAND
BUILDING AND CONSTRUCTION COMMISSION:
https://www.qbcc.qld.gov.au/sites/default/files/BCA%20Classes%20of%20Building.pdf
Reid, R. N. (2000). Roofing & Cladding Systems: A Guide for Facility Managers. The Faitmont
Press, Inc.
SA.GOV.AU. (2018). The Building Code of Australia. Retrieved May 30, 2018, from
SA.GOV.AU: https://www.sa.gov.au/topics/planning-and-property/land-and-property-
development/building-rules-regulations-and-information/the-building-code-of-australia
STANDARDS AUSTRALIA. (2009). Construction of buildings in bushfireprone areas. AS 3959
- 2009 . STANDARDS AUSTRALIA.
.