3D Building Information Modeling Facilitates Accurate Cost Estimation to Avoid Budget Overruns
Posted: Dec 03, 2013
As the property owners increasingly demand timely and in-budget completion of projects, all the key stakeholders are increasingly adopting 3D BIM modeling to achieve the same. Whilst the traditional design-bid-build project delivery methods are still significantly used by the AEC industry, the AEC firms employing the same increasingly run the risk of cost overruns. Furthermore, the risk factor escalates as the complexity and scale of the build project increases. Since the core team consists of professionals from highly diverse trades, the collaborative BIM workflows, when used within the design-build and integrated project delivery (IPD) frameworks, help avoid drastic cost overruns.
One of the key advantages of BIM modeling over non-BIM 3D modeling and 2D CAD techniques is that the former facilitates rapid and accurate cost estimation during all phases from design through to construction. The ability of 3D BIM models to generate accurate quantity and material takeoffs play a crucial role in enabling better decision-making with respect to project modifications whilst reducing costly budget overruns. Whereas accurate cost estimation is critical during the planning and conceptual stage to seek the owner’s approval, it is equally decisive during the construction stage to keep the entire team in the know of the implications of their design modifications.
The cost estimates derived from conceptual BIM designs ensure feasible decisions are made early on in the design and planning process, which in turn, govern the eventual project cost. As a result, such a valuable cost feedback in the initial stages of the project helps build a strong foundation for the latter stages of the project. Moreover, since the combination of 3D BIM workflow and IPD brings together all the multidisciplinary professionals during the pre-construction phase, such precise cost estimations keeps all the major stakeholders well informed about the financial implications of their decisions. More importantly, this risk and reward-sharing framework facilitates smooth information-sharing and better decision-making so as to keep the project on-track and within budget.
In order to realise the benefits of cost estimation during the design phase, it is critical to integrate the BIM models with an external database which contains costing information relating to quantity takeoffs. Compared to the traditional method of cost estimation, BIM-led cost feedback improves accuracy, offers time savings, and increases the speed of estimation. Whilst setting up BIM-based cost estimating the workflow requires planning, its benefits overshadow the time and effort required to do so.On the whole, detailed quantity takeoffs resulting from BIM models help key decision makers to consider several what-if scenarios and compare the cost impact of each alternative during all phases of the design and construction. These detailed cost estimates also enable key project stakeholders to assess the deviation in cost from the the planned budget at every stage and make all necessary corrections. Accordingly, BIM-driven cost estimation ensures the entire team can share budget-related inputs, perform cost-benefit analysis of multiple design options collaboratively, and most importantly, curb costly, time-consuming design conflicts and rework.