The Problem with Construction Verification, and How To Fix It

Author / Sean Higgins

Construction is incredibly complex. Each project sees hundreds of companies and thousands of people collaborating on a unique, one-off project while trying to hit the lowest price point—making it inevitable that some work will be poorly installed or out of tolerance.

The real problem for a construction project is not the error itself, but the lag between making the mistake and discovering it. A simple error that goes unnoticed (and uncorrected) could cost hundreds of thousands of dollars. More serious errors are likely to require significant rework, leading to scheduling delays, rushed work downstream, more errors, more scheduling delays, and mounting costs.

That’s why it’s crucial for today’s projects to use comprehensive QA workflows that can quickly find and document variances between the original design and what was actually built. Since there is no cost-effective QA mechanism available that meets these requirements, too many errors are missed before it’s too late, costing the construction industry an estimated $450 billion every year.

Here are the problems with current QA mechanisms, and the new tools that can fix them.

What’s wrong with traditional QA?

The day-to-day reality on the job site is that existing workflows for QA simply won’t scale to verify 100% of installed work. These traditional QA methods present a number of challenges.


Low Efficiency

Most projects use manual tools like total stations and tape measures, which are too slow to use for comprehensive checking.


Incomplete Coverage

Most projects will spot check, verifying only the most critical objects—about 5-10% of installed work—and lay the results out plan view. This means that a small number of errors are recorded, and in two dimensions only.


Inadequate Results

To complement the spot checks, projects rely on the insight of overworked superintendents, architects, and engineers.

3D tech offers a better option

In the past decade or so, the widespread adoption of reality capture in construction has promised a better way to verify construction work. Laser scanners and photogrammetric technologies, which capture millions of measurements for an as-built in every possible dimension, are improving at a rapid clip and getting more affordable by the year.

On the other side of the equation, design and construction firms have adopted BIM practices widely, leading to a proliferation of 3D models for fabrication and design. This produces an unprecedented amount of geometric data for use in 3D verification efforts.

The idea is simple enough: Capture the as-built 3D data set with a laser scanner, and use software to compare it against the design and fabrication models and spot errors.

What’s wrong with 3D QA methods?

The practical reality is that most 3D-capture workflows for construction QA still present a number of practical difficulties.


High Cost

3D capture workflows are slow to capture and require sending multiple people into the field. They require using two or three different instruments (including total stations and laser scanners), which means associated expenses for maintenance and training.


High Technical Requirements

Individual scans need to be registered together by a trained specialist before they can be used for further QA analysis. This process is difficult, time-consuming, and costly.


Inadequate Reporting

Most software for construction QA relies on visual heat maps to show variance. Users still need to inspect all elements and take measurements manually to generate final variance reports for sharing with other stakeholders.

The good news is that all of these pain points can be overcome with the right tools.


A new generation of tools combine robotic total stations and laser scanners into a single device, enabling one worker to capture 3D as-built models while they are performing layout. These tools make it possible to get comprehensive, detailed data quickly, and offer smart feature sets that automate the most complex portions of the workflow.

By combining these scanners with an intelligent, automated QA software optimized for the needs of construction QA, contractors can get actionable data in nearly real time. This enables them to deliver on the promise of 3D data by checking 100% of work in the same time it takes to spot check 5%.

These workflows offer a number of benefits over previous processes:


Improved Field Efficiency

With a scanner and total station in one, a single employee with no previous 3D experience can capture layout and comprehensive as-built information in a single setup—eliminating the need for multiple employees and tools.


Fast, User-Friendly Workflows

Some of these devices, like the GTL-1000, automate registration and survey control. This cuts a number of slow, complex processing steps from the workflow, and improves ease of use so any AEC professional can capture and process the data.


Advanced Variance Reporting

QA tools optimized for construction, like Verity, use advanced algorithms to compare the as-built data against the design model. That means they automatically produce element-by-element numerical analysis of the difference between the two.


Smoother Stakeholder Communication

QA tools optimized for construction offer methods for sharing variance reports, 3D data sets, and design models with stakeholders for faster remediation.


Advanced Variance Reporting

QA tools optimized for construction, like Verity, use advanced algorithms to compare the as-built data against the design model. That means they automatically produce element-by-element numerical analysis of the difference between the two.

For more information about our advanced construction QA workflow, which combines the GTL-1000 laser scanning total station and our Verity QA/QC software

Sean Higgins is an independent technology writer, former trade publication editor, and outdoors enthusiast. He believes that clear, buzzword-free writing about 3D technologies is a public service.