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Is Renovation with BIM Technology a Cheaper Alternative to New Construction

The greatest challenge when undertaking a renovation project is the unknown & hidden condition of the existing building. This article describes how to develop a strategic BIM plan for the renovation process of existing facilities.

Reasons to Renovate

There are several reasons driving a decision to renovate old inadequate or dysfunctional buildings in preference to demolition and new construction. Sustainability through recycling is increasingly becoming a strong motivation for renovations in order to limit the dependence on new building materials. However, reuse of building materials, while lowering the cost to the environment, will almost always lead to higher labour costs and need to be carefully evaluated as to the net benefit before going down this path.

Challenges

The first and greatest challenge when undertaking a renovation is the unknown and hidden condition of the existing building. Over time all buildings deteriorate, and all old buildings can be expected to have deteriorating drainage, plumbing, and electrical service runs that need replacing. A cursory inspection would also easily reveal sagging or cracking structure, either due to inadequate bracing, or foundation movement. Such issues are fairly easy to predict and budget for in the renovation program.

In addition to the problems of deterioration, rectifications are often needed due to changing building standards (e.g. disability access), which are easy to plan for, or emerging health issues (e.g. asbestos, lead paint, CCA), which will only be revealed in a thorough building audit.

In order to minimise the risk of cost and time overruns it is crucial that as most of the latent problems are identified at the outset, and the optimal methods for dealing with them determined and factored into the program. Some problems can not be discovered at the outset, and a time and cost contingency allowance should be set aside for these commensurate with the risk of them occurring.

Solutions

It is readily acknowledged among AEC professionals that Building Information Modelling (BIM) greatly facilitates the whole process through design to completion for new construction. For renovation projects there are several additional benefits in the BIM process.

The first step of a renovation project is a full survey and a building audit by each of the consultants in their area of expertise. One emerging technology that is beginning to revolutionise the building survey is the use of laser scanners. Laser scans from strategic points in and around an existing building generate what is called a PointCloud data set. A PointCloud can best be thought of as a 3D bitmap which can then be inserted into BIM software such as ArchiCAD, Revit and so on. Using this as the accurate dimensional guide, the various Building Information Modelling components are then generated to make up the Building Information Model.

A Building Information Model of existing conditions facilitates the analysis and efficient coordination of data gathered by the consultant team in their building audit. It becomes the database where this information is collated and problem areas highlighted. Points of deterioration and dilapidation, as well as essential load bearing structure, can be identified. This information base in the form of a Virtual Building becomes an easily readable logical framework from which the design and program for the renovation can then be developed.

The visual feedback through the use of BIM also makes it easier to make sound strategic decisions regarding the staging of the renovation program and the logistics of achieving the end result within an already existing structure, a significant problem in large buildings on crowded sites.

The various BIM software packages now have features that facilitate renovation documentation: Thus the Renovation filters in ArchiCAD are tools specifically used to identify and colour code Existing components to remain, Components for demolition, Temporary work, and New construction. Timelines can be applied to this and construction animations generated to highlight issues of site logistics. Likewise the Phasing filters in Revit can be used to advantage in a similar manner.

These filters are mainly intended for broader documentation such as space planning and design changes, but in theory they could also be applied at the detail level, where many of the critical issues of renovations crop up, e.g. how to temporarily support a beam to replace a corroded seating bracket.

With the help of BIM, collaborating designers and engineers can in short order make more informed and better coordinated decisions about to what extent a dysfunctional old building should be preserved, remedied or replaced. Without BIM, construction professionals in Pisa have been grappling with this very question for just one building over the past 850 years!

Architectural and construction firms should adopt BIM to master their renovation business. But, just starting to create BIM model and draft in BIM software (Revit, ArchiCAD, Bentley, etc.) without knowing it properly is the biggest mistake and can bring in the worst return on investment. BluEnt is a leading architectural drafting and BIM consulting firm in USA, which collaborates with small and medium architectural and construction firms and helps them to implement the BIM process and BIM software, develop integrated BIM model; integrate BIM model with the project construction schedule and planning. BluEnt provides AutoCAD conversion, AutoCAD to Revit Conversion, PDF to Revit conversion, Revit construction documentation services.

The article is written by an Architectural Evangelist associated with Global Fraternity of Architects (GFA) who is working on implementing Building Information Modeling (BIM) at various firms in Sweden and Australia. He has depth interest in modern tools and technology and how to utilize them to develop the processes to make great buildings.

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