ADVISORS: Ang Lian Aik,Technology DevelopmentDivision (BCA); Aw PauHwee, TechnologyDevelopment Division(BCA); Goh Peng Thong,Alfred Wong PartnershipPte Ltd (SIA); Richard Lai,ADDP Architects (SIA);EDITOR: PunithaGovindasamy GRAPHICDESIGNER: Noor Hazmee(Trade Link Media)

PREFAB Architecture ispublished twice a year bythe Building andConstruction Authority(BCA), Singapore Instituteof Architects (SIA) andTrade Link Media Pte Ltd(TLM). The editorial team isunable to accept anyliability for errors oromissions that may occur,although every effort hasbeen taken to ensure thatall information is correct atthe time of going to press.No portion of thispublication may bereproduced in whole orpart without the writtenpermission of BCA. Tocontact the editorial team,please write to:aw_pau_hwee@bca.gov.sgor call Tel: 63255024

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Going PrecastThere is something about living by the waterside that ap-peals to many people. Perhaps it is the feeling of beingone with nature. Or it could be the sound, the ambience, orthe whole enchantment of living so close to a river or lake.

In the two projects that are featured in this issue ofPREFAB Architecture, the main attraction of each projectis the fact that the developments are located next to ariver. Besides giving that special ambience, the proximityto the river also plays a role in inspiring the design forriverside housing.

While Sanctuary Green blatantly projects the nauticaltheme through many of its forms and elements, Freesia

Woods is slightly more subtle with its message, incorpo-rating wave-like curves in its façade. It goes without say-ing that both designs were made possible by the flexibil-ity and precision offered by prefabrication techniques.

Of course the Kallang River and Sungei Ulu Pandanmay be just mini rivers compared to the magnificent oceanslocated all over the world. An excellent example wouldbe the Pacific Ocean where classic dream houses areperched atop the cliffs facing it. Nonetheless, riversidehousing developments in a tiny state like Singapore stillhave plenty to offer in their unique architecture and highquality finishes achieved through precast construction.

By Punitha Govindasamy

Watersideby the

PREFABarchitectureA BCA-SIA Publication 2004 • Issue No 1

2 2004 • Issue No 1

FREESIA WOODS

By Richard Lai Teck Chuan

reesia Woods, nestled amidst the low-risequality housing along Sunset Way, is a con-temporary and timeless expression of river-side living, characterised by spacious floorplates, tall windows, attics and balconies

all elbowing for attention and spaces close to the water.Set in a continental environment in harmony with the se-renity of the river and the nostalgic railway track, it is in-disputably a rare jewel for resort living. The developmentresponds to the solar orientation through its north-southfacing layout and provides a wholesome view of the wa-ter and to some units, an unobstructed view of a hill at thefar end of Sunset Way. The building culminates from thegenerous pool deck into a picturesque pitch roof appa-rent from the street level.

This prestigious development, awarded in 2001, com-

prises 129 units in 4 blocks of 5-storey apartments, eachoffering a choice of 1, 2+1, 3 and 4 bedroom apart-ments.

The main façade adopts a layering of the differentplanes depicting the extension of the unit into landscape,swimming pool and the river. This visual expression is ap-parent from the opposite side of the Sungei Ulu Pandanthat runs parallel to the development.

Precast wall panels with bay windows and bottom-hang windows provide not only a visual extension of thebedrooms but also a practical provision whereby windowscan remain open under wet weather conditions allowinggood natural ventilation within the unit.

Precast planters in front of the living and dining areasprovide another layering to the façade creating a softertouch to the concrete structure and complementing the

The PrecastWave

Wave-like curved moulding on precast balconies typifying flowing water at Sungei Ulu Pandan.

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Mediterranean look of the development.The various types of precast air-con ledges and the

projecting precast balconies create the layering of thefaçade including the wave-like curved moulding typifyingthe flowing water at Sungei Ulu Pandan. All of which wouldnot have been successfully executed without precastingas the quality and consistency in the finishing work couldeither make or break the beauty of the alluring façade.

Apart from the façade of the units, the other elementsalso adopt various forms of precasting. They include stair-case façades that are both flat and curved, flights of stair-case including the landings, walls of the lift core and rein-forced concrete parapets.

These precast elements were integrated into the con-ventional in-situ beam and column frame structure con-struction through collaboration between the precaster and

FREESIA WOODS

Creating a Mediterranean look using precast facade.

Installation of precast components in progress.

4 2004 • Issue No 1

the structural engineer to ensure a good fit in rebar posi-tioning during the erection. The precast elements are easyto install and need only simple touch up work after instal-lation.

All the precast concrete façade elements were de-signed as critical elements, which had to be installed priorto the casting of the horizontal floor structure. Such designensures better water tightness performance, which is un-doubtedly expected from a typical external wall.

In conclusion, precast construction implemented pri-marily for the external façade has led to a highly consist-ent alignment for all floors, which has aesthetically addedto the overall effects of the development and the qualityof finishing required of the façade and balconies.

FREESIA WOODS

Riverside living at Freesia Woods.

Layering of the facade.

The synchronised precastwaves echoed in the pool.

52004 • Issue No 1

FREESIA WOODS

Curved precast staircase wall along Sunset Way.

PROJECT TEAMClient : Keppel Land Realty Pte Ltd

Contractor : Santarli Construction Pte Ltd

Architect : ADDP Architects

C&S Engineer : DE Consultants (S) Pte Ltd

M&E Engineer : Alpha Engineering Consultant

Quantity Surveyor : Davis Langdon & Seah (S) Pte Ltd

Precaster : Excel Precast Pte Ltd

Single integrated precast staircase walls withlandings and steps. Reinforcement bars from theprecast staircase walls are extended into the in-situ columns

SANCTUARY GREEN

Tensile sail at the entrance.6 2004 • Issue No 1

anctuary Greenanctuary Greenanctuary Greenanctuary Greenanctuary Green comprises 522 units, spreadover 5 tower blocks, which range from 7 to19 storeys in height. So far, 3 blocks havebeen completed. The other 2 blocks are stillunder construction, with just interior and road

works left to go and should be completed by the middleof this year.

The architectural design for Sanctuary Green, a URAland parcel, was conceived with the ‘City - Waters - Re-sort’ theme which was in line with URA’s aim to provideresort style urban high-density waterfront development forthe Kallang Basin. Although the terms ‘resort’ and ‘urban’may seem contradictory, it actually opens up exciting pos-sibilities for fresh ideas.

The vibrancy of the city that is only an 8-minute driveaway coupled with images of water scenes, exude asense of festivity and excitement which the designscheme follows closely. The site’s natural orientationtowards the sea is blatantly felt in the strong resorttheme.

Some of the forms adopted for Sanctuary Green arederived from nautical symbols too. From sand stone tex-ture entrance buttress walls, to the highly raked roofscapesand the tensile sail at the entrance, the affinity to wavebreakers, sails and masts cannot be missed. The theme isalso carried throughout the soft and hardscape elementsin the open spaces with boat-shaped play equipments,boardwalk pedestrian linkages and beach resort poolconcept with palms and frangipani trees at the pool deck.

The roof profile comprising a simple two-sided pitch isvery much a part of the overall nautical theme. Coupledwith different building heights, the waffle pitch roofs looklike sails in a free spirited roofscape.

This project was originally conceived to have externalplastered brickwalls, which was later changed to precastfaçades instead. Being denser, precast façade not onlyhelps to minimise water seepage but also improves thebuildability of the project. In addition, precast façade ex-udes unparalleled smoothness and precise alignment thatis most obvious under the bright afternoon sun.

SANCTUARY GREEN

Resort styleUrban Home

Sand stone texture buttress walls.

72004 • Issue No 1

By Yvon Yap

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8 2004 • Issue No 1

SANCTUARY GREEN

The effectiveness of water-tightness, which is quite cru-cial in precast projects, depends greatly on the design ofjoints and the type of sealant used. In this project, theprecast façades were secured in place by dowel barswhich were extended from the precast façades into thecast-in-situ columns and beams. A simple rebate was cre-ated around the edges of the precast façade panels andpolyurethane sealant was used to fill up the joints. In ad-dition, a 50 mm recess was created on the edge of thefloor for the precast façade to sit on to act as a seconddefence line against water seepage.

Other precast components used in this project includebalconies, staircases and parapet walls. In particular, thecreative mix of curved, triangular and rectangular precastbalconies reflects the ‘plasticity’ of precast concrete.

The production of more complicated precast compo-

Excellent surface and alignment achieved through precast construction.

Casting of precast façade on site.

92004 • Issue No 1

SANCTUARY GREEN

nents such as staircases were carried out in the factory.The tight quality control in the factory enabled the desireddimensions, shapes and textures of the components to beachieved easily. The relatively simple precast façade pan-els were cast on site to minimise handling and transpor-tation costs.

By combining precast and cast-in-situ construction tech-niques, the amount of wet trades was reduced significantly.Furthermore, the contractors managed to deploy their re-sources more efficiently without relying too much on heavyequipment like tower cranes.

The successful conversion from plastered brickwall toprecast façade shows that precast design is a viable so-lution for residential projects. The use of precast construc-tion has enhanced the quality and aesthetics of the over-all project.

PROJECT TEAMClient : Sanctuary Land Pte Ltd

Contractor : Kimly Construction Pte Ltd

Architect : SEP Partnership

C&S Engineer : Engineers Partnership

M&E Engineer : Technocon Engineers (S) Pte Ltd

Quantity Surveyor : Jia Quantity Surveyors & ProjectManagers Pte Ltd

Precaster : Kimly Construction Pte Ltd / Poh CheongPrecast Pte Ltd

View from the pool. Interplay of circular and triangular precast balconies withoctagonal roofs provides exciting variations to the façade.

Picturesque night view ofurban waterfront living.

10 2004 • Issue No 1

his tilted precast concrete house, within theexpanse of suburbia between Perth andMandurah, is located in a cul-de-sac over-looking one of the greens of the MeadowSprings Golf Course. Without any architec-

tural reference point to draw from, the idea was to havethe dwelling fold back in on itself, self-referencing butparadoxically contextual. The front and side walls of thehouse lean back at seven degrees as if buckling underthe pressure or vacuum that surrounds it. From the street,the solidity of the concrete panels dissolves into glass atthe rear of the building, where it opens up to take in northlight and air as well as views to the garden and golfinggreen opposite.

This freestanding suburban house, comprising threebedrooms, a study, two bathrooms, an upper-level mez-zanine, a ground level open plan living/dining/kitchenand an enclosed double garage, was built in approxi-mately seven months.

Given the temperate climate, the thermal mass of theconcrete walls and floor slabs assist in stabilising tem-

peratures within the dwelling. Passive solar design prin-ciples were integrated into the overall concept. As a re-sult, there are no east or west facing windows. South-facing windows are small and well-protected with pro-truding plywood window-boxes fixed directly to the con-crete panels. Extensive glazing was concentrated on thenorth side of the dwelling under protective overhangs,allowing solar winter gain and summer shading as wellas accessing views to the golf course.

The construction system adopted was precast con-crete panels and concrete ground and suspended slabs,tied together at the top of the panels with the roof steel-work. All the panels span vertically, in some cases overtwo floors to the void areas. These were achieved using150 mm thick panels. The single-storey garage panelswere reduced to 125 mm thick. The motivation for usingthis construction method was to achieve some degree ofefficiency in construction time and cost.

Significant cost savings were achieved by doing awaywith plasterboard linings to the internal precast panels.The panels were steel trowelled to a smooth finish on

THE BUNKER, MEADOW SPRINGS, WESTERN AUSTRALIA

InclinedPlanes

(From left) Front façade - passive design principles were integrated into the overall concept; Viewfrom cul-de-sac showing inclined concrete planes.

Precast

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112004 • Issue No 1

one side during the precast production process giving apolished finish. The concrete panels joints were cleanedup on site and skimmed using 10 mm negative profiledexpansion joints internally and standard silicon joints ex-ternally. A standard grey concrete mix was used to keepcosts down. At the Main Entry, recessed bands runninghorizontally between windows and vertically at the entrywere cast into the panels and used as graphic devices toarticulate the south façade.

The advantages of a precast system to the builderwere an accelerated construction period and minimaltime required for external and internal scaffolding. As forthe architect, the major advantage was the freedom thatprecast concrete allowed in the design process withoutturning to lightweight construction. Achieving the inclinedfront wall at seven degree was relatively easy with brac-ing to the suspended slab and roof steel. The recessedbanding was also achieved easily and cost effectivelywithin the thickness of the panels. Almost all the precastconcrete was painted externally in the shades of cream/white and internally in shades of white/grey. The external

THE BUNKER, MEADOW SPRINGS, WESTERN AUSTRALIA

PROJECT TEAMArchitect: Joe ChindarsiStructural Engineer: Burdett & AssociatesBuilder: Developments WestPrecaster/Concretor: Go-Crete Pty LtdPhotography: Joe ChindarsiClimate: Warm temperateDwelling Type: Detached, two-levelThis article first appeared in C&CAA Journal,Mix Volume 11 Jan 2003.

(From left) Rear north-facing façade has extensive glazing with protective overhangs; Verticalrecessed bands were used as a graphic device and cast into the panel at the front entrance; Frontfaçade detail showing timber window brise-soleil.

panel finish was smooth enough not to warrant the use ofa textured paint, a further cost saving. The recessed band-ing was simply clear-sealed to express the true colour ofthe grey-concrete panels beneath, the vestige of an origi-nal idea to leave the whole exterior of the house in itsraw and natural concrete state.

12 2004 • Issue No 1

THERMO HOUSE, TOORAK, VICTORIA

The design intent for this three-level resi-dence was to showcase the benefits ofliving and working in a high thermal massconstruction by using insulated concretesandwich panels. The result is a unique

family home with a finely executed design, predomi-nantly in concrete. The architect has achieved a feelingof lightness with heavyweight materials through carefulmanagement of proportioning and finishing of the build-ing envelope.

Family accommodation extends over the ground andfirst floors while the basement level is divided betweenguest accommodation and office for the Melbourneheadquarters of Composite Systems Pty Ltd. This resi-dence is one of an asymmetrical pair designed by deCampo Architects.

The principle structural elements consist ofThermomass precast walls and hollowcore precast con-

crete planks for floor/ceiling/roof slabs that were allmanufactured and installed by the one contractor. Otherexposed concrete elements include a staircase of float-ing concrete treads, wet area surrounds in bathroomsand shower-base.

The precast walls comprise an inner leaf of nomi-nally 150 mm concrete, a 50 mm interlayer of Styrofoaminsulation and an outer skin of 65 mm concrete tiedtogether with composite-fibre thermal connectors. Thissystem provides a fully insulated internal thermal masswith the added benefit of external solid construction.The Thermomass walls throughout the residence bothinternally and externally have almost all been left asplain grey as-delivered concrete. A square edge wasspecified for all the panels giving a less industrialisedappearance while maintaining a sense of solidity. Re-cessed caulking details were specified at smaller paneljunctions.

T

High Comfort-Low EnergyBuilding using

Insulated Concrete Sandwich Panels

132004 • Issue No 1

The concrete roof is constructed using hollowcoreconcrete slab as the structural unit with a 60 mm screedplaced over as a binding slab. A waterproof bitumi-nous membrane was installed directly over the screedwith a layer of expanded polystyrene placed over it.

Shop drawings for the precast panels requireddiligent assessment and checking to ensure a con-tinuous thermal envelope was specified at complexjunctions, notably at three axis-plane intersections.This was closely monitored during manufacture toensure the thermal envelope was maintained at paneljoints, around corners and at the connection to roofslab. Care during delivery and installation was alsorequired to maintain quality control and avoid dam-age.

The result is a home with a very high comfort leveldue to the acoustic and thermal properties of the tech-nologies employed.

THERMO HOUSE, TOORAK, VICTORIA

PROJECT TEAMArchitect: de Campo ArchitectsStructural Engineer : Bruce Adams Consulting

EngineersBuilder/Concretor: Lucchese & DonazzonManufacturer/Installer : Westkon Precast

Concrete Pty LtdPhotography: Shannon McGrathAwards: Francis Greenway, Society GreenBuildings Award, 2002 Bronze MedalClimate: Mild temperateDwelling Type: Semi-attached, three-levelAcknowledgement: Chris de Campo, de CampoArchitects; Mikael Carlstrom, CompositeSystems Pty Ltd; George Cremasco, WestkonPrecast Concrete Pty LtdLink : www.compositesystems.com.auThis is an edited version of an article that appeared inC&CAA Journal, Mix Volume 11 Jan 2003.

(Clockwise from left) Precastconcrete stairs; Front façadeshowing a mixed palette ofconcrete and timber elements;View of dining area -Thermalbridging of wall to windowjunction were resolved withcarefully prepared shop drawingsfor the precast concrete walls andslabs; The north-facing living areais designed to admit and storesolar gain during the coolermonths with high thermal massconcrete elements.

Prime Structures EngineeringPte Ltd is a staunch followerof the building industry’ssteadily growing trend to-wards design and build. Its

strengths include innovation, in-depthknowledge, and comprehensive facilities

coupled with a team of experienced en-gineers. Through strategic alliances, it hassuccessfully completed projects inSingapore, Malaysia, Brunei, Thailand,Hong Kong, Taiwan, Sri Lanka, Africa andthe Middle East.

From January 2004, with more em-phasis being placed on the buildabilityof wall systems, the weightage for wallshas been increased from 30 to 40 pointsin the revised Buildable Design Code ofPractice. This is where Finewall with itshigh Labour Saving Index will come inhandy to increase the buildability scoresof projects significantly.

Installation of these dense and robustpanels is a breeze as they are lightweightat only 68 kg/sq m. The walls can be cutand fixed on-site with simple tools suchas a saw, wood chisel and wood drill.The smooth finish surface of the panelsalso eliminates the need for wet workssuch as plastering. Finewall, with itsunique combination of strength, qualityand buildability is ideal for most projects.

Finewall has been successfully used

Innovativebuildablesolutions

(Clockwise from botton left) The Istana Park; King’s Centre; NUH Radiotherapy Centre; The Esparis.

CONTACTPrime Structures Engineering Pte LtdTel : 65 6454 0822Fax : 65 6454 0877Email: primestr@singnet.com.sgWebsite : www.primestructures.com.sg

Finewall from Prime Structures.

in many private residential projects suchas The Esparis, Changi Rise, Nuovo, Em-ery Point as well as commercial projectslike the PWC Building. Besides Finewall,Prime Structures also offers a range ofinnovative products such as system glassor polycarbonate skylight, system balljoint spaceframe and custom-made orpre-fabricated steel and aluminium struc-tures.

Besides enhancing buildability, theseproducts also add creative touches to theaesthetics of the buildings. This range ofproducts has been used in prominentprojects such as King’s Centre, glass con-servatory in Botanical Gardens and theIstana Park.

14 2004 • Issue No 1

Worley can provide specialist expertiseas follows;

• Optimisation analysis of structure• Structural Engineering design and documentation• Development of systems to suit geo- graphic, cultural and cost require- ments• Precast shop drafting and detailing• Load testing and verification of con- nections or structural members• Structural certification and submission to the authorities• Training of labour by experienced con- struction supervisors• Construction supervision

SAMPLE PROJECTS

TANGLIN VIEW (SINGAPORE)Client: Chiu Teng / Multiplex JV

This S$80 million project was initially ten-dered using conventional construction.An alternative bid using precast concretewalls and slabs, and a grouted tempo-rary retaining wall was accepted as thewinning bid.This project won the prestigious "BestBuildable Design Award" given by theBuilding and Construction Authority ofSingapore in 2002 and was the JointWinner of the MBA National Exporterof 2002 for Building and ConstructionContractors.

Worley is a publicly owned multi-disci-plined engineering consultancy, estab-lished throughout Asia.

Worley encapsulates the technology ofa number of divisions of specialised en-gineering consultants covering all as-pects of the engineering services indus-try. The Worley group forms one of thelargest multi-disciplined consultancyoperations in the Asia Pacific region.

Worley Industrial and Infrastructure isthe customer service group withinWorley that delivers projects in the Build-ing, Transport, Industrial and Defencesectors.

Our group’s vision is to be seen by allof our clients as the engineers andproject managers of choice. We striveto deliver innovative solutions alignedto Client objectives. Our focus on work-ing closely with our clients has providedexceptional outcomes on other projectsby continually striving to:

• Successfully deliver projects, by understanding our clients needs

• Select high quality individuals and create a rewarding working environ- ment

• Commit to long term relationships with our clients

• Test the norms and seek creative, cost effective, whole of project solutions.

• Be a pro-active team player and de- velop innovative solutions

SPECIALIST BUILDINGSYSTEMSWorley, in association with its clients,has developed specialist building sys-tems that specifically suit the needs ofthe contractor, developer and end user.Systems have been developed on largeresidential projects which have highrepetition, with the result of reducingconstruction costs whilst improving qual-ity and speed of construction. The In-dustrial and Infrastructure group hassuccessfully designed in excess of20,000 apar tments in Australia,Singapore, Malaysia and Thailand.

ENGINEERING EXPERTISESPECIALIST BUILDING SYSTEMS

SINGAPORE491-B River Valley Road#09-01 Valley PointSingapore 248373Tel: 65 6735 8444Fax: 65 6735 7444Email: singapore@worley.com.au

WEBSITEwww.worley.com.au

OIL & GAS | REFINING, PETROCHEMICALS & CHEMICALS | MINERALS & METALS |POWER & WATER | INDUSTRIAL & INFRASTRUCTURE | DEVELOPMENTS

YARRA CONDO (MELBOURNE, AUST.)Client: Auscor / Thiess

This A$25 million project consists of asingle 19 storey structure, with the first 3stories being a car park podium. An al-ternative bid adopting the Ultrafloor (atype of precast plank) flooring system andprecast load bearing walls and columnswas presented and accepted as the win-ning bid.

KERRISDALE (SINGAPORE)Client: Kimly Construction Pte Ltd

The project consists of 520 apartmentsin 3 buildings of 31 storeys each and a 6-level post tensioned carpark. Worleyproduced an alternative precast designwhich was subsequently adopted for theproject. Precast was used for the exter-nal facade walls, planter boxes and allinternal walls.Insitu concrete was adopted for the lift/stair walls, columns and slabs. Worleyproduced precast shop drawings for allprecast elements of which there areapprox 30,000 in total. All precast ele-

ments were cast on site, and lifted di-rectly using the tower crane.

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16 2004 • Issue No 1

Several local contractors havebeen increasingly enjoying thebenefits of the innovative pre-cast design of WP Brown, anAustralian firm that has been

providing personalised service with atechnological edge in Singapore for thepast 12 years.

WP Brown designed precast shellcolumns for the Sengkang Primary SchoolDesign & Build project (below), enablingNeo Corporation to eliminate all formworkat the beam joints. Lapping of the co-lumn bars did not require sleeves or grout-ing and there was also considerable sav-ings in the crane costs as a result of thelighter components.

Goldenhill Villas, a residential deve-lopment of 83 terrace house units (be-low) was constructed by Tiong Seng Con-tractors using full precast construction de-signed by WP Brown. The precast load

bearing party walls proved to be neatand cost-effective. To simplify the instal-lation of the precast beams to the walls,a pocket system was used. This alsohelped to eliminate the formwork for cast-ing the wet joints.

WP Brown’s precast beam and slabdesign made construction over a 6-storeyhigh void relatively easy for Poh Lian Con-struction at the Amaranda condominiumsite (below). Substantial time savings werealso achieved because all propping waseliminated.

The Nuovo EC project in Ang Mo Kiofeatures a precast floor system andfaçade panels designed by WP Brown(below). Custom designed prestressedprecast slabs were used to minimise thenumber of floor beams. The curved can-tilever floor for the master bedroom usedprecast slabs with an integral fascia and

CONTACTWP Brown Pte LtdTel : 65 6291 1221Fax : 65 6291 2221Email: singapore@wpbrown.com.auWebsite : www.wpbrown.com.au

ledge, avoiding the need for difficultformwork and the associated quality con-trol issues at site.

For Esparis EC, Ando Corporationadopted precast components for all ver-tical elements and the entire facade re-sulting in improved quality and speed ofconstruction and the elimination of exter-nal scaffold. WP Brown's design conceptincluded load bearing external walls, de-signed as plain concrete members (be-low). Economy is achieved because theconcrete in the panels is contributing tothe building structure, whilst the plain con-crete design minimises the number ofvertical bars to be lapped at each floorlevel.

These case studies show the resultsof WP Brown’s strong emphasis on de-sign for buildability, technical strength andexperience in precast design and con-struction.

16 2004 • Issue No 1

ofPrecast DesignMaximisingtheBenefits