“Trust, But Verify” is a Russian proverb. It was used often in the context of nuclear disarmament during the Cold War era by Ronald Reagan and meant the United States can trust the Soviet Union, but they need to make sure they won't betray the United States.
This is where we have made an error that lead us to refund the money for site survey to our client.
Correct As-build plans are the foundation of the whole project, if we get this wrong the whole new design will be based on wrong measurements. This will lead to wasted time, lost money, and frustration for every one. Not the scenario that we are looking for!
So the correct scan data of the site visit is crucial for the architect or ourselves but we have failed this time!
Anyone involved in construction especially surveyors like ourselves that carry the responsibility for delivering as built drawings or 3d models need to be aware of these potential pitfalls and learn from our mistakes.
Wrong position of the tree trunk, missing canopy heights and multiple site visits.
What Happened? Our client requested additional information for this project, specifically the exact tree trunk locations and canopy heights throughout the tree's height.
As per our standard topography practices, we show tree locations at their base, with the canopy represented as an average. However, the client required precise canopy height details.
In the initial process, the point cloud was cleaned to remove the tree canopy, ensuring a clearer view of the building. This approach simplifies drafting and reduces file size, particularly for the front elevation, where the tree was obstructing the view of the house. Consequently, the canopy data was not retained.
To meet the client's needs, we scheduled the revisit to capture the full canopy details and tree trunk positions of the trees in front of the property. At this time not knowing that there will be more revisist, this was just the beginning...



The client later also requested to confirmation the exact tree location in the rear topography, where it had also been shown only at its base. Identifying the trunk’s correct position was challenging, it was obscured by grass and bushes, and the trunk itself was crooked.
To meet the client’s requirements "Show the precise trunk location at every height and map the sprawling canopy" which extended across the neighboring garden. We needed to do a second site visit, which, as it turned out, wouldn’t be the last. 😢



As if two revisits weren’t enough, it turned out that our drawing was 204mm (20.4cm) shorter than the actual side elevation!
So what happened here? The client was unsure about our plans when he compared them to their old plans. He even did a site visit himself and manually measured this one measurement in question. Client found a discrepancy of 204mm, which is totally unacceptable.

What's the Big Takeaway?
It reminds me of something my father used to say:
“What’s the difference between a professional and an amateur? Professionals make fewer mistakes.”
Why? Because professionals have years of experience, filled with lessons learned from their own mistakes. That’s why I am sharing this story not just to reflect on our journey of learning from own mistakes, but to help you avoid these pitfalls and learn from our experience.
This is why having a robust quality control process is essential: it catches errors before they become costly, waste your and the client’s time, or delay the entire project.
How do we fix it?
Once the client raised the issue, we knew we had to dive into the investigation. Despite the client making their own amendments and amendments to the delivered plans, it was crucial for us to pinpoint where the problem originated, so we could prevent it in the future.
The worst case scenario? Repeating the same mistake over and over again without realizing there is a potential error.
So, we scheduled another revisit 😭. During our investigation, we discovered that the issue was indeed on our end a misalignment with the scan data.
The drafting team didn't noticed this, as the plans matched the scan data perfectly. But the scans themselves had been incorrectly registered, and that was on our surveyor’s shoulders.
We had to rescan the entire area and carefully realign the side elevation to prevent any further misalignment. Our surveyor conducted a few additional scans to ensure we had enough data and to avoid low overlap in the scans, as this is where the original mistake had occurred. The issue arose from rushing through that part of the site survey.
Since this was only an external survey, it was tricky to identify the misalignment in the office. Had we scanned the interior of the property, we would have noticed the mismatch between the interior and exterior walls.


This was the first time we encountered such misalignment, we never anticipated it as all our previous and projects went smoothly.
It was clear the issue wasn’t with the equipment. Instead, the misalignment stemmed from the sheer volume of work during an insanely busy season.
The mistake occurred when our surveyor rushed through the job and registering the scans. As we typically rely on scan data as the "true" data for drafting and modeling. We learned that the scanners also struggle in tight spaces with limited reference points, like the alleyway between two buildings where the misalignment happened we we just need to take additional extra scans in these spaces to ensure this doesn't happen again.
Since this case, we've spotted a similar issue in another project, but thankfully, it was only a 20mm (2cm) discrepancy compared to the 204mm (20.4cm) misalignment above.
THE END
Overall, this project had 6 deliverables, and the client was satisfied with the rest of the drawings. These were the only two areas where the client experienced inaccuracies: the tree canopy location in the topography and the side elevation.
We refunded the fee we charged for the site survey because, at the end of the day, it was our mistake, and we needed to fix it. The client shouldn’t have to spend their time and energy on work that should have been done by us. In fact, this client helped us to help them!
With our surveys, we usually save architects one to two weeks of work, and I truly believe that the better work we provide to architects, the easier their lives will be.
Thank you, everyone, for your feedback and for helping us grow. We’re proud to support you in your business and help you reclaim time in your life.
Take home message
We need to avoid rushing the process and assuming that everything is ok. We need to be careful and double check before we send final deliverables to clients. And we also need to be open to feedback and learn from our mistakes.
“Trust, But Verify”
Peter Bauman

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