Preventing or at the very least minimizing the cost of rework is an efficient and effective way to cut costs on a construction project. Studies have shown, the average cost of re-work on construction projects is 5% of the project value!
These rework overruns can be down to many factors, but there are some culprits that usually come up trumps when contributing to additional unnecessary costs. Some of these are:
- Design Co-ordination – Poor coordination within the design team and is another age-old issue when it comes to additional costs on projects. Without good communication and the required attention to detail from all sides of the design team, the likelihood of issues on site such as clashing of services and structure is high. It is clear from our experience that putting the work in at the design stage to ensure coordination is correct saves the client money at the end of the day.
- Design Errors – Design errors can be a major factor in the overall scale of issues that lead to rework on site. In a study conducted in the US in 2012 of 179 projects, the average total percentage of rework was 5.2%, of which 1.8% was due to design errors.
This is a clear example of the importance of getting the design right before it gets to site! This doesn’t just lie with the design team carrying out detailed design, however, as a good client brief is as important as any element of a project.
- A strong client brief – this is also one of the main factors relating to rework on construction projects, the second highest factor in the aforementioned study was owner changes. While these are not always avoidable, they can be reduced by good planning. It is important the client engages a design team from the outset of a project at the conceptual stage to advise the client of any potential banana skins when writing the project brief.
- Over-engineering – something that can be an oversight until it is too late. Overengineering can not only lead to higher construction costs in general, costing the client more money than necessary, but can also lead to confusion when the project is being priced and built on site.
- Builders Works – it is common in traditional construction projects for the consultant team to prepare a schedule of builders openings, or a set of 2D drawings identifying builders works, without inputting the necessary detail to ensure all openings are fully accounted for. This invariably leads to variations from the contractor when they get to site and realise there are additional works required. Another common theme of builders works issues is when the MEP services have not been accurately co-ordinated with each other and with the building structure at the design stage. This leads to re-coordination of services on site which changes the requirements for builders works leading to additional costs.
Errors resulting in the need for rework can happen at any time during a project but are particularly costly if they happen early in project planning and are not caught until the final survey.
The introduction of BIM and 3D modeling has made the task of designing out issues such as those identified above a simple task once done properly. We can now offer detailed builders works drawings, models, and schedules to ensure the costs associated with these are kept under control.
Measuring the Impact of Rework on Construction Cost Performance; Bon-Gang Hwang; Stephen R. Thomas, M.ASCE; Carl T. Haas, M.ASCE; and Carlos H. Caldas, M.ASCE - https://doi.org/10.1061/(ASCE)0733-9364(2009)135:3(187)
THE IMPACT OF REWORK ON CONSTRUCTION & SOME PRACTICAL REMEDIES A Research Perspective Issued by the Navigant Construction Forum™ Jason M. Dougherty LEED AP1, Associate Director Nigel Hughes LEED AP2 Associate Director, James G. Zack, Jr. CCM, CFCC, FAACEI, FRICS, PMP3 Executive Director Navigant Construction Forum™ https://cmaanet.org/sites/default/files/2018-04/IMPACT%20OF%20REWORK%20ON%20CONSTRUCTION.pdf