Designing for cost cuts
Jimmy Abrahim, chief quantity surveyor, Specialised Aluminium & Steel Company, discusses how integrating specialist subcontractors into design and engineering at an earlier stage can lead to cost-effective fa?ade construction.
The approach to building façades has changed dramatically in recent years, from considering them as a mere outer skin which gives a predetermined appearance to the building, to complex integrated and active systems. The evolution triggered from the realisation that more than the appearance, the performance of the façades plays an influential role in the overall performance of the building.
As an interface of the building and its occupants to the outer environment, the ffaçades are significant components of solar energy transmission, light transmission and ventilation. Every major project in the region wants to be treated as more of a 'one of a kind' entity and the building façade contributes greatly to provide this distinct personality to the building and its owner. The architects strive to reach this by breaking new grounds in the realm of design by introducing technologically advanced solutions, which tread a different path from the commonly employed technological solutions in façade construction.
The sourcing, integration and engineering of resources and technologies required to achieve this architectural and engineering solution is costly and consumes a lot of valuable time and effort. One example is that the majority of architects dream the glass used for the façade should be the largest available in the market, with very little visible support, while the structural engineer worries about its structural stability; the estimator loses sleep thinking about the additional cost implications due to glass wastage and support structure reinforcement, and the project engineer is concerned about the practical difficulties of handling, fabrication and fixing.
It is necessary to consider the cost effectiveness and cost saving methodologies, since the cost of façade construction and its influence on the overall construction project is increasing rapidly. This becomes apparent when it comes to façade renovation and façade replacement of existing buildings, where façade cost has a major share in the total project cost.
Cost savings in façade construction can be achieved greatly by involving a specialist façade subcontractor or appointing a façade consultant from the early design, planning and engineering stage of the project itself. Currently, the subcontractor's role is limited at the final stage of a civil construction project, and he is forced to construct from a complete set of architectural drawings which mainly focus on the appearance and performance of the building. Their influence on the building design is limited and this, in turn, limits their ability to apply and develop new technology to facilitate cost savings. Unlike most other components of the building,façades vary greatly from one project to the other and the methods which helped to save cost and time to one may not apply to others. This demands more of a façade specialist's vast knowledge and experience in this field rather than the generalised knowledge and experience of a general building consultant or architect.
Materialising a design to reality in the way it is conceptualised can be difficult when it comes into conflict with practical engineering problems. The involvement of the façade subcontractor from the conceptual design stage helps the architects or designer generate a conceptual design, which matches close to the final requirement of the building. The façade subcontractor can identify the practical problems and suggest alternative solutions so that the designer may achieve his design objective without obstruction throughout the project. The extra cost and delay in the project for altering built structures to suit design, preparing drawings and getting approvals from consultants or architects at the advanced stage of the project can be avoided. The experienced subcontractor can also help minimise labour intensive designs and can help in developing work-simplifying methods.
The consultant can use the relevant general drawings and typical details existing with the façade specialist, which helps to optimise drawing preparation and control sequence of preparing it, to avoid delay project delays. This also avoids ambiguities in drawings, since it creates much confusion when estimating, preparing fabrication drawings and construction. These misleading threads in drawings force the estimator to propose options which have the highest cost, while technical and construction teams go for the lengthy process of approvals and clarifications of each and every minute details from the consultant or client.
The façade specialist can provide a more realistic project cost break-up since unlike commonly employed square meter pricing, which has the risk of moving either to the higher or lower side, he consider the façades as a heterogeneous system and calculates the actual cost based on the material, labour and other factors involved in the project. This helps to conduct comparative analyses of cost versus usefulness of different components of the façade and helps in negotiating with different contractors.
Significant benefits can be obtained by properly integrating specialist knowledge and expertise with project design and engineering. The project cost and schedules can be minimised by effectively applying latest technology and expertise.