1. pg. 1
BACHELOR OF QUANTITY SURVEYING
QSB 1514 CONSTRUCTION TECHNOLOGY
LEE PEI GIE 0315653
TEE SIN YI 0315689
KHOO XIN YEE 0316180
LEONG CHEE MUN 0316256
THAN LEK MEI 0315538
YONG SEEN YEE 0315883
Submission date : 17.11.2014
2. pg. 2
CONTENT TABLE
No. Content Pages
1 Part 1
About PJ Trade Centre
3 - 8
2 Part 2
i) Types of Foundation
ii) Types of Slab
iii) Types of Roof
9
10 – 12
13 – 16
17 - 19
3 Part 3
Compare and Contrast
i) Foundation
ii) Slab
iii) Roof
20
21 – 24
25 – 27
28 – 30
4 References 31
4. pg. 4
PJ TRADE CENTRE
“ The idea behind PJ Trade Centre (PJTC) starts with the observation that office
development in Malaysia, and generally in the region, is often not based on the optimal
solution. The typical glass, steel and aluminium box is repeated over and over again,
regardless of the local culture, climate, context and construction methods. There seems to
be a need for all office developers to follow the same direction in order to gain credibility.
The glass boxes get more and more complex, more and more uneconomical. It seems very
difficult to change and do something different. ”
With plenty of natural light and cross-ventilation, PJ Trade Centre is designed as
comfortable and healthy workplaces. Energy-efficient and eco-friendly design features
lead to lower maintenance costs, but more importantly, has the potential to boost
productivity - reduce absenteeism, improved staff morale, higher work quality.
Instead of focusing on the usual Western-style office designs, which proliferate across
Malaysian cities, the architect, Kevin Mark Low has came up with the idea based on local
culture, climate and context. There is a feeling of being close to nature, with a lushly
landscaped Plaza of 2.5 acres and 12 Sky Terraces with hanging vines and wall creepers.
Many office units have balconies of about 325 square feet and open-to-sky washrooms.
PJ Trade Centre reflects a 'boutique' property - there are only 1 to 4 units per floor with a
minimum size of 2,100 square feet. Each unit has its own pantry and washroom and
higher than normal ceilings of 3.8 metres.
Prepared by Than Lek Mei
5. pg. 5
Appealing unfinished brick walls
The buildings here were built referring to western countries as the walls were not covered
by cement. The entire PJ Trade Centre is mostly built by bricks. It makes the building
looks distinctive among the other buildings.
Prepared by Than Lek Mei
6. pg. 6
Attractive concrete appearance
The concrete elevation stairs in PJ Trade Centre.
The relaxing zone and waiting area for guests in PJ Trade Centre.
Prepared by Than Lek Mei
7. pg. 7
Lush green
These are the patio in PJ Trade Centre with surrounding covered by lush green.
Prepared by Than Lek Mei
8. pg. 8
Lembaga Hasil dalam Negeri located in PJ Trade Centre.
One of the impressive things we found is the lift outside of Lembaga Hasil office
designed for the disabled people.
These are the separate block in PJ Trade Centre which are Bata and Gamuda
headquarters.
The buildings are built up with
glass window. It makes the
building looks wider and
brighter with natural light.
This building is also built up
with glass flat roof which
provides natural light.
The concrete beams.
Others
Prepared by Than Lek Mei
10. pg. 10
FOUNDATION
DEFINITION
Foundation is the lowest load-bearing part of a building, typically below ground level. It
is the most important part of the construction that provides support to the building and
also transferring the loads of buildings to the below ground level.
PURPOSE OF FOUNDATION
The first purpose of a foundation is a building will always move when it is built. It can
sink, rise, slide, or combine these motions. Therefore, foundations ensure that the load of
a building is spread evenly over the ground underneath the building. The second purpose
of a foundation is to tie the different parts of the building together so that it does not sink
unevenly and crack. Finally, foundations anchor the building to prevent its moving
sideways when, for example, it is built on sloping ground.
Prepared by Yong Seen Yee
11. pg. 11
TYPES OF FOUNDATION
Foundations are generally divided into two categories:-
Shallow foundation
Shallow foundation is a type of foundation which transfers building loads to
subsoil at a point near to the ground floor of a building. The example of shallow
foundations is strip foundation, trench foundation, raft foundation and pad
foundation.
Deep foundation
Deep foundation is a type of foundation which transfer load to subsoil some
distance below the ground floor of a building which is contrast to shallow
foundation. The example of deep foundation is piled foundation.
Different types of building have to use different types of foundation. It is depend
on various condition and applications such as ground condition, the presence of
water, the nature of the load requiring support, accessibility, sensitivity to noise
and vibration, proximity to other structures and project time frames.
ADVANTAGES OF FOUNDATION
1. Piles can be precast to the required specifications.
2. Piles of any size, length and shape can be made in advance and used at the site. As a
result, the progress of the work will be rapid.
3. A pile driven into granular soil compacts the adjacent soil mass and as a result the
bearing capacity of the pile is increased.
4. The work is neat and clean. The supervision of work at the site can be reduced to a
minimum. The storage space required is very much less.
5. Driven piles may conveniently be used in places where it is advisable not to drill holes
for fear of meeting ground water under pressure.
6. Driven pile are the most favoured for works over water such as piles in wharf
structures or jetties.
CHARACTERISTIC OF PILE FOUNDATION
Pile foundations are considered as deep foundations. It is a group of piles that supports a
superstructure. Pile cap will connect with the piles together and distributes the
superstructure loads to the layer beneath. They are formed by long, slender, columnar
elements typically made from timber, steel, concrete, or a combination of these materials,
usually forced into the ground to transfer the load to underlying soil or rock layers.
Prepared by Yong Seen Yee
12. pg. 12
Pile foundations are used to transfer the loads from a superstructure, through weak,
compressible strata, more compact, less compressible and stiffer soil or rock at depth.
Normally, they are used for large and heavy structures, and in situations where the
surface soils at a proposed site are too weak or compressible to provide enough support.
WAYS OF TRANSFERRING STRUCTURAL LOADS
These are several ways of transferring structural loads into the subsoil on sites where
ground conditions are unfavourable. The bearing capacity of the subsoil can be increased
by ground improvement techniques such as end-bearing pile, friction pile and the
combination of end bearing & friction pile.
• End bearing pile
End bearing piles are piles that are driven vertically and used for the direct support of
vertical loads are called bearing piles. Bearing piles transfer the load through a soft soil to
an underlying hard layer. They also distribute the load through relatively soft soils that
are not capable of supporting concentrated loads.
• Friction pile
Friction piles are the piles that driven into soil of fairly uniform consistency and the tip
are not seated in a hard layer, the load-carrying capacity of the pile is developed by skin
friction. The load is transferred to the adjoining soil by friction between the pile and the
surrounding soil. The load is transferred downward and laterally to the soil.
• A combination of end bearing and friction pile
Most piles use some end-bearing and some friction, in order to resist the action of loads.
It is a fairly soft soil that provides frictional resistance and then into a form layer which
develops a load carrying capacity.
ANALYSIS
In conclusion, we found that the foundation of PJ Trade Centre is pile foundation. There
are a few reasons why the pile foundation is used as the foundation for this building (PJ
Trade Centre). First of all, PJ Trade Centre is a multi-storey building which consists of
very high carrying heavy concreted loads. PJ Trade Centre comprises of a 21-storey
tower, four 20-storey towers and a 2-storey annex building. The soil is very soft as solid
base is not available at a reasonable depth to keep the bearing power within safe limits.
Besides, the condition of the soil is too weak and compressible. Therefore, it would be
more suited for this building to use pile foundation in order to provide a strong and
durable base to support the load of the building.
Prepared by Yong Seen Yee
13. pg. 13
SLAB
DEFINITION
Slab is a flat piece of concrete, typically used as a walking surface, but may also serve as
a load bearing device as in slab homes.
FUNCTIONS OF SLAB
Provide a flat surface
Support load
Sound, heat and fire insulator
Act as a divider for the occupants
Upper slab acts as the ceiling for the storey below
Space between slab and ceiling can be used to place building facilities
Prepared by Lee Pei Gie
14. pg. 14
TYPES OF FLOOR SLAB
Concrete slabs come in various forms, which can be divided into two categories – precast
or in situ, depending on where the concrete was cast. Wherever the concrete is casted it
may be reinforced or prestressed. Reinforced concrete uses steel bars to resist the tension
in the slab. Prestressed concrete has high strength steel strand cast in it which compresses
the concrete and maximizes the benefit of concrete compressive strengths.
1) PRECAST CONCRETE FLOORS
Reinforced concrete is widely used for the construction of suspended floors for all types
of buildings. Floors composed of reinforced precast concrete units have been developed
over the years to overcome some or all of the disadvantages of in-situ reinforced concrete
slab such as needs for formwork, time taken for the concrete to cure before the formwork
can be released for reuse and the floor available as a working area, and very little is
contributed by a large proportion of the concrete to the strength of the floor.
Advantages of Precast Concrete Floors
Very rapid speed of erection
Good quality control
Entire building can be precast-walls, floors, beams, etc.
Rapid construction on site
High quality because of the controlled conditions in the factory
Pre-stressing is easily done which can reduce the size and number of the structural
members.
Disadvantages of Precast Concrete Floors
Very heavy members
Camber in beams and slabs
Very small margin for error
Connections may be difficult
Somewhat limited building design flexibility
Because panel size is limited, precast concrete
cannot be used for two-way structural systems.
Economics of scale demand regularly
shaped buildings.
Prepared by Lee Pei Gie
15. pg. 15
2) IN-SITU CONCRETE SLAB
In situ reinforced concrete slab options include :
Ribbed ( Waffle ) Slabs Flat Slabs
Ribbed floors consisting of equally spaced
ribs are usually supported directly by
columns. This form of construction is not
very common because of the formwork
costs and the low fire rating. Ribbed slabs
are suitable for medium to heavy loads, can
span reasonable distances, are very stiff
and particularly suitable where the soffit is
exposed.
Flat slab is a reinforced concrete slab
supported directly by concrete columns
without the use of
beams. Flat slabs are highly versatile
elements widely used in construction,
providing minimum depth, fast
construction and allowing flexible column
grids.
Advantages
Savings on weight and materials.
Stability - A waffle slab gives a substance
significantly more structural stability
without using a lot of additional material.
This makes a waffle slab perfect for large
flat areas like foundations or floors.
Attractive soffit appearance if exposed.
Economical when reusable formwork pans
used.
Vertical penetrations between ribs are easy.
Advantages
Construction - Construction of flat slabs is
one of the quickest methods available.
Lead times are very short as this is one of
the most common forms of construction.
Cost, whole life cost, value - Flat slabs are
particularly appropriate for areas where
tops of partitions need to be sealed to the
slab soffit for acoustic or fire reasons. Flat
slabs are considered to be faster and more
economic than other forms of construction,
as partition heads do not need to be cut
around downstand beams or ribs.
Flat slabs can be designed with a good
surface finish to the soffit, allowing
exposed soffits to be used. This allows
exploitation of the building’s thermal mass
in the design of heating, ventilation and
cooling requirements, increasing energy
efficiency.
Disadvantages
Depth of slab between the ribs may control
the fire rating.
Requires special or proprietary formwork.
Greater floor-to-floor height.
Disadvantages
Drop panels may interfere with larger
mechanical ducting
Vertical penetrations need to avoid area
around columns
For reinforced flat slabs, deflection at the
middle strip may be critical.
Prepared by Lee Pei Gie
16. pg. 16
ANALYSIS
During site visit at PJ Trade Centre, we found that the buildings are mostly made of the
unfinished brick and concrete and it is interesting in the way it manages to meet the
ground without clutter. PJ Trade Centre comprises of a 21-storey tower, four 20-storey
towers and a 2-storey annex building. Thus, there are ground floor slab and suspended
slabs. Nonetheless we are only allowed to access the building to first floor, so our
analysis will be based on ground floor slab first and second floor slab.
Ground Floor Slab
According to our analysis, we suggest that the ground floor slab used in PJ Trade Centre
is in-situ concrete slab. While the type of in-situ concrete slab used is flat slab. The slab
design is designed to be reinforced in several directions so that it can withstand stresses.
Furthermore, it is flexible to the occupier who can easily alter internal layouts to
accommodate changes in the use of the structure. With the introduction of drop panels at
column locations the form work becomes slightly more complex than that of a flat plate
but it is still a relatively simple procedure and the drop panels add to the shear strength of
the slab.
Suspended Floor Slab
As for suspended floor slab, we suggest that the in-situ concrete slab is used as well in
first floor and second floor slab. What different from ground floor slab is that the type of
in-situ concrete slab used is ribbed ( waffle ) slab. Resembling the food after which they
are named, the type of slab used is reinforced concrete floors and roofs that use a square
grid of deep sides. This form of construction is usually used in airports, parking garages,
bridges, residences and other structures requiring extra stability. In addition, it is also
used in commercial and industrial buildings like PJ Trade Centre.
Prepared by Lee Pei Gie
17. pg. 17
ROOF
DEFINITION OF ROOF
A roof protects the building and its content from the effect of weather.
IMPORTANCE OF ROOF
I. Durability
A higher quality roof will long lasting than low quality roof. It will be more likely
to stand up under the routine wear and tear of sun, wind, rain and storms.
II. Protection
Roof’s primary job is protection. As a low quality roof, it doesn’t perform well on
this job.
III. Efficiency
Roof serves as a vital heat and humidity release valve for ours house. Proper
insulation creates a transitory heat zone that can help ours home stay warm in
night and rainy day.
Prepared by Leong Chee Mun
18. pg. 18
FUNCTION OF ROOF
I. Human Protection
Roof is to provide protection to person inside a structure from the elements.
Without a roof, inhabitants inside a structure would be directly subjected to all
these weather changes and suffer the physical ailments that result from this
exposure.
II. Protection of Possessions
Possession such as furniture, carpet and appliances will be ruined quickly when
rain water inside the structure.
FLAT ROOF
Flat roofs are an often lower cost and easier to install alternative to traditional pitched
roofs. A flat roof is a roof which is almost level in contrast to the many types of sloped
roofs. The slope of a roof is properly known as its pitch and flat roofs have up to
approximately 10°.
TYPES OF FLAT ROOF SYSTEM
1. Rubber Roof
It holds up against severe weather, temperature changes fire and leaks is an
extremely durable surface. The costs of rubber roof is higher than an asphalt
shingle product, however rubber roof offer a long lasting product that is very
durable and resistant to cracking, fading and crumbling.
2. Ethylene Propylene Diene Monomer (EPDM)
This compound is highly UV resistant, waterproof, heat resistant and extremely
adaptable to cold weather changes, ice and snow, therefore it is most effective
tool in flat roof today. EPDM can be used on any type of roof system, including
roof top gardens, ponds, tunnels, terraces and on RV roofs making this the most
durable and adaptable roofing product found today.
3. Asphalt Build Up Roof (BUR)
Multiple layers of reinforcing layers and asphalt go into building. These roof uses
tar and gravel, which are most common. This flat roof system becomes dry and
brittle in the sun and shows signs of cracks quickly. These tar and asphalt are very
inefficient and required a great deal of energy to install. Therefore, the lifespan of
BUR may only be eight to ten years.
Prepared by Leong Chee Mun
19. pg. 19
ADVANTAGES AND DISADVANTAGES OF FLAT ROOF SYSTEM
ANALYSIS
After visiting PJ Trade Centre, we found that PJ Trade Centre is using flat roof as their
protection since flat roof is the best choice on very large size building. Installing a pitch
roof on such a building is not recommended, because it will be a lot more difficult, costly
and will require special engineering to accommodate the additional structural weight.
Besides, PJ Trade Centre is built as a green building therefore flat roof was chosen as
priority because it is energy efficiency which considered to be highly reflective up to
90% of heat back into the atmosphere.
Advantages Disadvantages
Allows for walk decks to be
incorporated
Very easy access
Easy installation of solar panels.
Less framing materials when
building a home
Very reflective and provides a
very energy efficient roof system
in the warm climates.
Lifespan for a felt flat roof of
only 20 years
Drainage or lack thereof
Limited capacity for insulation
More expensive to repair
Prepared by Leong Chee Mun
21. pg. 21
FOUNDATION
In this part, we will be comparing the construction material that is foundation with two
other different types of each of them.
1) RAFT FOUNDATION
A raft foundation consists of a raft of reinforced concrete under the whole of a building.
Raft foundations may be used for buildings on compressible ground such as very soft
clay, alluvial deposits and compressible fill materials where strip, pad or pile foundations
would not provide a stable foundation without excessive excavation. The reinforced
concrete raft is designed to transmit the load of the building and distribute the load over
the whole area under raft, reducing the load per unit area placed on the ground (Figure
3.21).
Distributing the loads in this way causes little, if any, appreciable settlement. The two
types of raft foundation commonly used
are the flat raft and the wide toe raft.
The flat slab raft foundation may be used
under small buildings such as bungalows
and two storey houses where the
comparatively small loads on the
foundations can be spread safely and
economically under the raft. The concrete
raft is of uniform thickness and reinforced
top and bottom against both upward and
downward bending.
Prepared by Khoo Xin Yee
22. pg. 22
When the reinforced concrete
raft has dried and developed
sufficient strength walls are
raised as illustrated in Figure
3.22. The concrete raft is
usually at least 150mm thick.
In areas subject to mining
subsidence the flat slab is cast
on a bed of fine granular
material, 150mm thick, so that
the raft is not keyed to the
ground and is therefore
unaffected by horizontal
ground strains. Where the ground has poor compressibility and the loads on the
foundations would require a thick, uneconomic flat slab, it is usual to cast the raft as a
wide toe raft foundation. The raft is cast with a reinforced concrete stiffening edge beam,
from which a reinforced concrete toe extends as a base for the external leaf of a cavity
wall, as shown in Figure 3.23 and 3.24.
PAD FOUNDATION
Pad foundations can be used to carry point loads, They can also be designed so that the
loads of the walls and the buildings are transferred through ground beams that rest on the
pad foundations. Pad foundations transfer the loads to a lower level where soil of
sufficient load bearing strata exists (Figure 3.19). The width of a pad foundation can be
increased to distribute the loads over a greater area, thus reducing the pressure on the
ground.
Prepared by Khoo Xin Yee
23. pg. 23
CONTRAST BETWEEN PILE FOUNDATION, PAD FOUNDATION AND RAFT
FOUNDATION
Pile Foundation Pad Foundation Raft Foundation
Costing
The most expensive
and the strongest
type of foundation.
The least expensive
among the other two
(Pile foundation and
Raft foundation)
It is more expensive than
pad foundation but
cheaper than pile
foundation
Strength/Quality
Strongest type of
foundation
Pad foundation is not as
strong as pile
foundation, considered
the weakest among the
other two (Pile
foundation and Pad
foundation)
Stronger than Pad
foundation but not as
strong as Pile foundation
Machinery
Requires big
machineries such as
bigger cranes to build
something big
(skyscrapers, etc.)
This type is easier to
construct and don’t need
some machineries that
are required for pile
foundation.
This type is easier to
construct and don’t need
some machineries that
are required for pile
foundation.
Labour
Requires specialist
engineering to do
Pile foundation
Skilled workers not
really needed,
depending on the
building
Needs skilled workers
sometimes, but not as
skilled as to do Pile
foundation depending on
the building
Sustainability/
Resistance
Better
resistance/bearing
capacity compare to
the other types
Considered having
lower resistance
compared to Raft
foundation and Pile
foundation
Raft foundation
resistance is higher
compare to other types
except pile foundation
Time
Requires more time
to build
The quickest to be done
compared to the other
two (Pile and Pad
Foundation)
Faster to be done than
Pile foundation but not as
quick as Pad foundation
Prepared by Khoo Xin Yee
24. pg. 24
RECOMMENDATION
In our opinion, PJ Trade as a high-rise building is usually founded on some form of piled
foundation which is subjected to a combination of vertical, lateral and overturning forces.
Combined pile-raft foundations can be a particularly effective form of foundation system
for PJ Trade building because the raft is able to provide a reasonable measure of both
stiffness and load resistance.
For the detailed information about the piled raft foundation, it utilizes piled support for
control of settlements with piles providing most of the stiffness at serviceability loads,
and the raft element providing additional capacity at ultimate loading. Consequently, it is
generally possible to reduce the required number of piles when the raft provides this
additional capacity. In addition, the raft can provide redundancy to the piles, for example,
if there are one or more defective or weaker piles, or if some of the piles encounter
caustic conditions in the subsoil. Under such circumstances, the presence of the raft
allows some measure of re-distribution of the load from the affected piles to those that
are not affected, and thus reduces the potential influence of pile “weakness” on the
foundation performance.
Another feature of piled rafts, and one that is rarely if ever allowed for, is that the
pressure applied from the raft on to the soil can increase the lateral stress between the
underlying piles and the soil, and thus can increase the ultimate load capacity of a pile as
compared to free-standing piles.
The most effective application of piled rafts occurs when the raft can provide adequate
load capacity, but the settlement or differential settlements of the raft alone exceed the
allowable values.
The actions or loads acting on a high-rise building which is PJ Trade is higher. The loads
include the composite column, reinforced concrete (RCC) walls, superimposed dead
loads consist of loads of permanent fixtures and fittings such as ceilings, air-conditioning
ducts, floor finishes, partitions. All these tremendous loads need a stronger foundation
that can support more loads. Therefore, piled raft foundation is a good choice as the raft
can help to transfer the load to the ground and it is supported by the piles. Furthermore,
the presence of raft in piled raft foundation can provide redundancy to the piles. In
Damansara Perdana, it will rains heavily or rains continuously, hence the water is drained
into the foundation and cause the erosion of piles. However, the raft can allows some
measure of re-distributions of the load from the weaker piles to the healthy piles. In short,
the raft helps to reduce the influence of the weaker piles in the foundations. It makes the
whole foundation become more durable and safer. Overall, piled raft foundation is an
alternative to replace pile foundation of the PJ Trade Building.
Prepared by Khoo Xin Yee
25. pg. 25
SLABS
For this part, we will be comparing and discussing about two other types of
slabs instead of flat slab and ribbed slab.
PRECAST CONCRETE SLAB
After all, the concrete does not know it is precast, whether statically reinforced
or pretensioned which also known as prestressed. It is only when we consider
the role that this concrete will play in developing structural characteristics that
its precast background becomes significant. The most obvious definition for
precast is that it is concrete which has been prepared for casting, cast and cured
in a location which is not is final destination.
Precast concrete slab does
not require any formwork.
Besides, time taken for
concrete to cure in the
formwork can be
eliminated. It has better
quality control compare to
others. Moreover, precast
concrete slab does not need
many workers as in in-situ
concrete construction and
it is a fast completion of
construction project.
There are many types of precast concrete floor such as:
a) Precast hollow floors
b) Composite floors
Precast hollow floor units are available in a
variety of sections such as box planks/
beams, tee section, I beam sections and
channel sections. Composite floors are
combination of precast units and in-situ
concrete.
Prepared by Tee Sin Yi
26. pg. 26
Precast hollow slab
Precast hollow slab is more economic compared to in-situ floor die to reduction
in volume of concrete used, weight of reinforcement and size of foundation. It
is cheaper than composite. It goes without saying that in-situ concrete is not
required. On top of that, units are self centering so, no need temporary support.
Moreover, construction period is also shorter when using precast hollow slab
compare to others.
Composite Floors
Composite floor is the combination of precast units and in situ concrete. Precast
units that are usually prestressed/ reinforced with high yield bars are used to
provide the strength of the floor with the smallest depth practicable. At the
same time, it acts as permanent formwork to the in-situ topping that provides
the compressive strength required.
TIMBER FLOORING
Timber flooring has proven itself a timeless product, offering a warmth and
natural beauty largely unmatched by other flooring products. This guide
provides on overview to the installation method of solid timber strip flooring
over bearers and joists, timber based sheet flooring products and concrete slabs.
Timber flooring is typically supplied as either solid timber or laminated wood
products, made from layers of bonded timber. It fits together with a tongue and
groove joint and once in place, is sanded and finished. There is a wide variety
of species to select flooring from and the right species for a given application
will be dependent on numerous factors. Information relating to species
selection, environmental assessment, finish selection and recommended
maintenance routines are all provided within this guide.
Prepared by Tee Sin Yi
27. pg. 27
CONTRAST BETWEEN PRECAST CONCRETE, REINFORCED IN-
SITU CONCRETE AND TIMBER FLOORING
Precast concrete Reinforced in-situ
concrete
Timber flooring
Elimination of the need
for formwork
Formwork needed No formwork is
required. Easy to
construct and adjust on
site.
Less flexible in design
term
Embrace various shape Higher aesthetical value
compared to concrete
floor
Superior quality control
of product is possible
with factory produced
components
Better working
condition for the
building operatives
Easy on the home
owners’ feet and legs
(concrete slabs are hard
on legs and cold
underfoot)
Curing time of concrete
is eliminated therefore
the floor is available for
use as a working
platform at an earlier
stage
Construction can
proceed independently
of weather condition. It
is not necessary ti pay
for crane on site.
Allows the most
efficient placement of
heating systems. Perfect
choice when building in
potentially low lying
flood prone areas.
RECOMMENDATION
The alternative for replacing reinforced cast in-situ floor slab would be precast
concrete floor slab. It has a high durability while precast concrete is
exceptionally resistant to impact, corrosion, weathering, abrasion and other
ravages of time, reducing maintenance and operation costs. A low water-
cement ratio combined with good compaction and curing in a controlled factory
environment ensures a dense, highly durable concrete. Precast concrete is also
non-combustible with inherent fire-resistant capability, creating a safe envelope
that helps protect personnel, equipment and the building itself. This in turn may
be able to reduce insurance rates.
Prepared by Tee Sin Yi
28. pg. 28
ROOF
In this part, we will be comparing the construction material that is roof with two other
different types of each of them.
GABLE ROOF
Gable roof end is a pitched roof sloping on two sides.
The ridge board which is considered as the spine of the
roof runs along the center and the peak of the roof. The
common rafters are nailed to the ridge board and slope
downwards to the external walls resting on the wall
plate in a birdsmouth joint. The battens are placed
horizontally on the rafters on the opposite direction to
receive the appropriate covering.
Figure 13.0 shows cross section of typical gable
roof.
It is especially used in areas where the
climatic conditions are rainy and
contains high prevailing winds. Gable
roof contains more brickwork to provide
the gable end. The gable end or gable
face can be made up of brickwork or
timber cladding. The extra brickwork
provides faces to the building. Gable
roof is preferred over other types of roof
because the two inclination meeting at
the ridge board hence less woodworking.
The degree of slope provides additional spacing underneath where it is used for water
storage cistern, and services.
Brunei is a country whereby its climatic conditions are humid, hot and containing heavy
downpour throughout the year. This principle and this roof construction method can be
proved ideal for another roof alternative to be considered for our case of study for Pitched
roof is based on the principle of cold air-sink and hot air rises especially gable end attic
roof.
Furthermore it is easier to maintain and is less likely to leak. Unlike a flat roof, the
replacement of tile covering or timber will be easy for they are made of singular
individual units.
Prepared by Tee Sin Yi
Prepared by Tee Sin Yi & KhooXin Yee
29. pg. 29
HIP ROOF
Hip roof, also called
hipped roof, roof that
slopes upward from all
sides of a structure,
connecting the walls of
the building, having no
vertical ends. Trusses
are found in the interior
of the roof, designed
with short ridge boards,
having several types of
rafters: hip rafters, jack
rafters & common
rafters. There are many
different variations on
the basic “ hip roof "
design, created mostly
to suit different styles of
house.
Hip Roof
Hip and Valley The hips and valleys on a hip and valley roof describe the
points where the different parts of the roof meet.
Broken Hip and Valley Almost the same as a hip and valley roof, except that the roof
is not level - some ridges and points are higher than others.
Belcote Has a verandah attached that runs all the way around its
perimeter.
Prepared by Tee Sin Yi & KhooXin Yee
30. pg. 30
CONTRAST BETWEEN HIP ROOF, GABLE ROOF AND FLAT ROOF
RECOMMENDATION
I would recommend steep slope roofing. The justification is that slope roofing is more
suitable for high rise building.
Generally, roofing types and roofing products are typically divided up into two primary
categories, steep slope roofing and low slope roofing. Sometimes steep slope roofing is
also referred to as “residential roofing” due to the fact that most single family homes in
the U.S. are constructed with some sort of pitch or slope to the roof. Just as steep slope
roofing is often referred to as residential roofing, the term low slope roofing is oftentimes
synonymous with “commercial roofing”. Again, this is due to the fact that,
predominantly, commercial buildings have “flat” roof designs.
As a matter of fact, Petaling Jaya Trade Centre is a combination of residential building
and commercial building. Thus, low slope roofing or steep slope roofing are good choices
for that.
Roof slope is a very important aspect and it is considered the primary factor in roof
design. The slope of a roof has an effect on the interior volume of a building, the drainage,
the style, and the material used for covering. For example, if you notice water collecting
on the roof the problem is probably related to the slope. The style is affected too because
the framing of the roof changes the slope.
Hip & Valley Roof Gable & Valley Roof Flat Roof
Installation Involves more
construction & knowledge
Simpler & more
economical to build
Uses rubber rolls &
quicker to install
Space Trusses structures under
the roof, can contain
chimneys
Extra space for attic or
extra room & access for
maintenance
Can place beneficial
objects that settle on flat
surfaces
Cost Complex structure & more
construction time causes
costly price
Reduced price due to
popularity & easy
construction
Costly at first, but
beneficial in the long run
Durability Design causes wind
protection & strength,
arguably the best among
roofs
Very unsuited to windy
areas due to design,
which can peel off the
roof
Rubber layer makes it
durable for extreme
weather,scruffs,tears &
leakage
Suitability
(To environment of
original house)
Decent rain runoff ability,
longer eaves for shading.
Steep slope makes it the
best among roofs for
water runoff
Heat absorption &
insulation, suitable for
Malaysia’s dry & wet
seasons
Appearance Roof connects with walls
& has 4 slopes, allowing
use of gutters
Fully exposing 2 sides
allowing extra room
hence allows extra
windows
Horizontal base &
appealing looks when
patio & gardens are
placed
Prepared by Tee Sin Yi & Khoo Xin Yee
