As they consider the potential impact of digital site inspection on their operations and their bottom lines, industry leaders should focus on the costly but often under-prioritized issue of re-work. Numerous research studies over the years have shown that construction companies that emphasize technology interventions tend to achieve significant advantages in running and managing construction projects, leading to cost reductions and improved productivity. The massive potential impact of digital site inspection on re-work costs should give construction industry leaders confidence to continue pursuing advanced digitalization.
Re-work: A Hidden but Massive Cost
Re-work costs can be difficult to quantify. On-the-ground workers have little incentive to document re-work that managers might attribute to their own mistakes or inattention. Nevertheless, we know that re-work costs in the construction industry are massive. When 3D renderings are converted into thousands of 2D drawings, frontline workers find themselves juggling unwieldy paper models while simultaneously struggling with everything from inclement weather to impatient bosses and clients, language differences and poor lighting. Misalignments between the design office and the site, manual quality control processes, improperly trained workers, substandard materials and aging/malfunctioning machinery can further increase the likelihood of significant re-work. Consequently, re-work is considered to be almost inevitable. Most construction industry estimates conclude that re-work costs average around 5% of total contract value, although some studies have found that re-work may account for up to 35% of project cost. Meanwhile, one study found that around 30% of the total work performed by construction companies is actually re-work.
Remove those re-work costs and a construction business currently limping along at barely profitable margins would immediately transform into a remarkably resilient business.
True, traditional on-site construction has a higher band of tolerances, and re-work costs in that context will be on the low side. However, offsite/DfMA (Design for Manufacture and Assembly) construction requires exacting precision. When casting in controlled environment and assembling at the job site, any joinery deviation greater than 5mm cannot be mended at the jobsite, and will result in materials being scrapped and recast, which will impact both cost and schedule.
In any case, regardless of process-specific differences in re-work intensity, the simple fact remains that most construction firms are losing too much money and allocating too many resources to complete work that should have been done right the first time.
Digital Site Inspection: Evolving at the Speed of Light
Digital site inspection extends the 3D workflow from the design phase into the construction phase, overlaying the design models onto the actual site to identify deviations, ensure they are within appropriate tolerances, and avoid major re-work later. While there is currently no end-to-end digital site inspection solution on the market, orchestrating connectivity, hardware, software, and cloud storage can yield hologram overlays with millimeter accuracy while making all BIM data immediately accessible at the construction site.
For frontline workers, AR-equipped hardhats now allow users to visualize hyper-complex geometry, while a cloud data platform supports the hardware with computing capabilities and an AI-powered content management system. Such GPU-accelerated hardhats can allow teams to live-stream to design engineers remotely, so that the engineers can see what field teams are observing onsite, or they can save local copies of deviation in cases where offline work mode is necessary.
Frontline workers can also leverage tripod-mounted lidar scanners and a Common Data Environment (CDE) to upload a point cloud output on top of the designed 3D model to generate a deviation heat map. For construction companies that have already invested heavily in scanners, this approach to digital site inspection may be most cost effective.
For use cases in which both head- and tripod-mounted scanning solutions are problematic or unsafe, automated robots/robo-dogs equipped with scanner-driven progress monitoring systems can reduce re-work by producing deviation reports on an AI-powered data visualization platform built on a cloud-based CDE.
As digital site inspection continues to evolve, the construction industry can expect a growing ecosystem of both startups and established industry players to bring precision, ease of use and automation to new heights.
Re-work Cost Reduction: Observations from the Field
Digital site inspection is already yielding results for early adopters. It is particularly impactful when it comes to reducing re-pouring costs, as it allows field teams to overlay the design models during the cage and pre-pour (cage-in-mould with fittings) stages as well as during the after-cast phase.
Working with a strategic construction customer in UK, we were recently able to observe the impacts of digital site inspection not just on re-work costs, but also on long inspection times and cumbersome paper-based reporting. By integrating BIM across design and build with the help of a mixed reality (MR) solution, the company’s pilot project was able to achieve £40K in cost savings per month due to fewer rejections, as well as a 40% reduction in inspection time, a 10% capacity creation from reduced wastage, real-time problem identification and resolution, and a more auditable digital reporting ecosystem that can integrate with any non-compliance tools in the field.
Yes, implementing AR/MR-enabled digital site inspection can be complicated, requiring construction companies to orchestrate new hardware, software, platforms and partners. However, the persistent margin-killing legacy of re-work in the industry should encourage all construction firms to examine how bringing 3D inspection to the jobsite can solve what was long considered an unsolvable problem.