BACHELOR OF QUANTITY SURVEYING QSB 1514 CONSTRUCTION TECHNOLOGY

LEE PEI GIE 0315653TEE SIN YI 0315689

KHOO XIN YEE 0316180LEONG CHEE MUN 0316256

THAN LEK MEI 0315538YONG SEEN YEE 0315883

Submission date : 17.11.2014

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CONTENT TABLE

No. Content Pages

1 Part 1About PJ Trade Centre

3 - 8

2 Part 2i) Types of Foundationii) Types of Slabiii) Types of Roof

9 10 – 1213 – 1617 - 19

3 Part 3Compare and Contrast i) Foundationii) Slabiii) Roof

20

21 – 2425 – 2728 – 30

4 References 31

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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.

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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.

Attractive concrete appearance

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The concrete elevation stairs in PJ Trade Centre.

The relaxing zone and waiting area for guests in PJ Trade Centre.

Lush green

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These are the patio in PJ Trade Centre with

surrounding covered by lush green.

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.

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These are the separate block in PJ Trade Centre which are Bata and Gamuda headquarters.

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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.

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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

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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. 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 pileEnd 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 pileFriction 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 pileMost 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.

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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

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→ Upper slab acts as the ceiling for the storey below

→ Space between slab and ceiling can be used to place building facilities

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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 FLOORSReinforced 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

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2) IN-SITU CONCRETE SLABIn situ reinforced concrete slab options include :

Ribbed ( Waffle ) Slabs Flat SlabsRibbed 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.

AdvantagesSavings 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.

AdvantagesConstruction - 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.

DisadvantagesDepth of slab between the ribs may control the fire rating.

Requires special or proprietary formwork.

Greater floor-to-floor height.

DisadvantagesDrop 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.

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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 SlabAccording 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 SlabAs 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.

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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. ProtectionRoof’s primary job is protection. As a low quality roof, it doesn’t perform well on this job.

III. EfficiencyRoof serves as a vital heat and humidity release valve for ours house. Proper

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insulation creates a transitory heat zone that can help ours home stay warm in night and rainy day.

FUNCTION OF ROOF

I. Human ProtectionRoof 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 PossessionsPossession 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

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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.

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

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.

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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.

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.

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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

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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.

CONTRAST BETWEEN PILE FOUNDATION, PAD FOUNDATION AND RAFT FOUNDATION

Pile Foundation Pad Foundation Raft Foundation

CostingThe 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/QualityStrongest 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.

LabourRequires 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

Faster to be done than Pile foundation but not as

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two (Pile and Pad Foundation)

quick as Pad foundation

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.

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SLABSFor 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.

Precast hollow slab

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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.

CONTRAST BETWEEN PRECAST CONCRETE, REINFORCED IN-SITU CONCRETE AND TIMBER FLOORING

Precast concrete Reinforced in-situ concrete

Timber flooring

Elimination of the need Formwork needed No formwork is

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for formwork 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.

ROOF

In this part, we will be comparing the construction material that is roof with two other different types of each of them.

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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.HIP ROOF

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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 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.

Hip Roof

CONTRAST BETWEEN HIP ROOF, GABLE ROOF AND FLAT ROOF

Hip & Valley Roof Gable & Valley Roof Flat RoofInstallation Involves more Simpler & more Uses rubber rolls &

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construction & knowledge economical to build 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

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.

REFERENCES

http://www.roofportland.com/flat-roofing-portland-oregon/http://www.morganasphalte.co.uk/news/advantages-disadvantages-pitched-flat-roofing/

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http://conestogaroofing.com/FlatRoofSystems.htmlhttp://v5.books.elsevier.com/bookscat/samples/9780750650847/9780750650847.PDFhttp://www.ce.memphis.edu/6136/PDF_notes/F_slabs.pdfhttp://enginemechanics.tpub.com/14081/css/14081_349.htm http://environment.uwe.ac.uk/geocal/foundations/Fountype.htmhttp://www.abuildersengineer.com/2012/11/driven-piles-advantages-and.htmlhttp://www.tujuangemilang.com/pdf/wallstreet.pdfhttp://www.pjtradecentre.com/about.html

Chudley, R. (1974), Construction Technology: Floors and roofs. Published byLongman Singapore Publishers ( Pte ) Ltd.

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