Building exterior walls gradually deteriorate from daily exposure to wind, rain, earthquakes, and other factors, leading to issues such as cracks and tile detachment or falling. Exterior wall inspections (façade inspections) are essential to detect such deterioration early, ensure safety, and protect a building’s asset value. However, performing exterior inspections using traditional methods has been a time-consuming and labor-intensive task for everything from single-family homes to condominiums and large public facilities. This article introduces the latest tool that streamlines such inspections: LRTK. We explain in detail how smartphone-based AR (augmented reality) crack verification and geotagged photos enable accurate record management and transform exterior inspection workflows.

The Importance of Exterior Inspections and Traditional Challenges

If cracks or tile detachment are left unaddressed, serious risks can arise, such as internal corrosion from water ingress or accidents caused by falling façade materials. In fact, there have been incidents where portions of aged exterior walls have fallen and injured passersby, so building managers are required to conduct regular inspections and timely repairs. For used buildings, periodic inspections are recommended, and it is common practice to have experts survey the property before sale to understand its condition.

However, traditional exterior inspections have had the following challenges:

• Labor- and time-intensive: Inspecting high exterior walls requires erecting scaffolding or arranging aerial work platforms, and inspections themselves have typically required multiple workers spending long hours. The burden of a single inspection can be large, and depending on the building’s scale, it can take days and incur significant costs.

• Complicated record-keeping: Inspection results were generally recorded manually on drawings and ledgers. For example, a two-person team might have one person perform tapping and visual inspection while the other records deterioration locations on drawings or takes photos. Later, they would compile that information into a report, but it was easy to misidentify photo locations or make transcription errors onto drawings, making record management cumbersome.

• Risk of oversights: Relying on human eyes and manual work leaves room for oversights and missing records. It is difficult to thoroughly check an entire façade, and there have been cases where the recorded crack locations could not be identified later.

• Difficulty in continuous comparison: Even if you want to compare with a previous inspection, you can only pull out past photos and notes and compare them individually, making it hard to analyze long-term changes. As a result, prioritizing repairs and assessing deterioration progression took time.

Because of these challenges, improving efficiency and accuracy in exterior inspections has long been a key theme in the field. Amid expectations for DX (digital transformation) of exterior inspections using digital technologies, the smartphone-mounted all-in-one surveying and inspection tool LRTK has emerged.

Digitize and Streamline Exterior Inspections with LRTK

LRTK is a compact device mounted to a smartphone or tablet that consolidates tasks that previously required separate devices or steps into one unit. By combining a high-precision GNSS (GPS) receiver with a phone’s built-in LiDAR scanner, it enables site positioning, measurement, and record-keeping to be completed digitally on-site. Using LRTK revolutionizes the formerly analog workflow of exterior inspections.

Key features offered by LRTK include:

• High-precision 3D point cloud scanning: By scanning the wall surface with a smartphone, you can acquire the wall’s shape as high-precision point cloud data—an array of countless points. This provides an on-site digital 3D model of the building façade almost instantly.

• AR visualization of deterioration: Utilizing the scanned 3D model and position data, virtual information is overlaid on the real building via the smartphone screen. This allows cracks and other deterioration to be displayed in AR on-site for intuitive confirmation and recording.

• Geotagged photos: When you take a photo, the shooting location’s coordinates (latitude, longitude, height) and the camera’s orientation are automatically recorded. Each photo is tagged with location information so even a huge number of photos can be accurately managed later.

• Cloud data sync and sharing: Captured point cloud data, photos, and notes are saved to the cloud on-site and can be shared in real time with office PCs and stakeholders. The whole team can view the latest inspection data, making communication smooth.

• Automatic inspection report generation: Based on the recorded data, inspection reports can be generated automatically. Because photos are linked with location data, lists of cracks and layout diagrams can be output with a single click, significantly streamlining reporting tasks.

The next sections explain specifically how these functions change exterior inspections.

Record the Entire Façade with High-Precision 3D Point Cloud Scanning

One major feature of LRTK is capturing the current state through high-precision 3D point cloud scanning. With a dedicated high-precision GPS and the smartphone’s LiDAR, you can digitally record the façade’s shape down to the smallest detail. Whereas conventional methods involved taking photos section by section while referring to drawings, LRTK completes the task simply by walking along the façade with the smartphone.

The point cloud data obtained by scanning is a three-dimensional model that represents the wall’s positions and undulations as countless points. For example, sweeping LRTK along the façade will produce data capturing the entire wall, including areas with cracks or surface materials lifting, at millimeter-level (mm (in)) accuracy. Because the point cloud is highly accurate and minimally distorted, it serves as a reliable base material for later measurements or drawing comparisons.

With a digital 3D model, areas missed on-site can be reviewed in detail back at the office. If you scan a wide area of façade at once, you won’t have to worry about “forgetting to take a photo of that part.” Also, storing a point cloud of the entire building helps with comparing deterioration over time. By acquiring a new point cloud at the next inspection, you can visualize crack expansion or façade deformation by calculating differences from the previous data, providing material for judging deterioration progression.

Furthermore, LRTK’s GPS offers centimeter-level positioning accuracy (cm level accuracy, half-inch accuracy), so the acquired point cloud model becomes a highly accurate map tied to real-world coordinates. This enables integrated current-state records that include surrounding positional relationships and elevation references. Tasks that were previously difficult—such as checking overall building distortion or creating elevations—can be performed easily from the scan data.

Intuitively Identify Deterioration and Cracks with AR Display

LRTK uses the scanned 3D model and current position to enable on-site AR display. When viewing the building through the smartphone, virtual information is overlaid on the screen. For example, if you discover a crack and tap the screen to place a marker, that marker will appear attached to the corresponding location on the façade in AR. This allows you to digitally mark the deterioration you find on-site so it can be reviewed later.

AR display is powerful not only for recording but also for intuitive confirmation. While inspecting, simply looking around the smartphone screen highlights already marked crack locations visually, helping prevent missed inspections. Because you can immediately see “what has been checked” and “what remains to be checked,” you can inspect wide façade areas efficiently and without omission.

AR is also effective for team information sharing. When another technician visits the site after an inspection, they can point their phone and see the previously marked deterioration in AR, making it easy to identify the same locations. This is useful when repair crews need to understand deterioration locations beforehand. The sensation of digital information being attached to the real wall helps close the gap between “this was unclear in photos but obvious on-site.”

LRTK’s AR provides stable display with minimal positional drift thanks to high-precision positioning technology. Standard smartphone AR alone can gradually drift with prolonged use, but LRTK corrects position with GPS, reducing marker misalignment with the real world. This allows the AR function to be used reliably for accurate spatial understanding.

Geotagged Photos for Accurate Inspection Record Management

Inspections involve taking numerous photos, but with LRTK all photos are automatically geotagged, making record management dramatically more accurate and simpler. Traditionally, you had to annotate each photo with notes like “north face, east side at floor X” or write numbers on drawings to match photos. With LRTK, simply pressing the shutter stores the location where the photo was taken as data.

Specifically, when you take a photo with LRTK’s app, the system automatically records coordinates such as latitude, longitude, and height, the date and time, and even the camera orientation (azimuth). For example, if you discover a crack on the east face of a 10-story condominium and photograph it, that photo’s data will be linked and saved with information like “a crack located at height ○○ m (○○ ft) on the east face” (○○ m (○○ ft)).

The advantage of geotagged photos is that the photo’s location is obvious even later on. Even when handling a large number of photos, you can plot photo locations on maps or drawings and won’t need to guess locations from filenames or notes. In the management interface, thumbnails can be displayed alongside a map, or clicking a photo can bring up its marker on the map—allowing you to use inspection records organized as a database.

Because photos include location information, tracking changes over time is also easy. If you photograph the same coordinates as in the previous inspection, you can perform a before-and-after comparison of exactly the same spot. You can accurately compare whether a crack has expanded or new deterioration has occurred without positional discrepancies, making it easier to decide on appropriate repair timing.

Cloud Sync for Immediate Sharing of Inspection Data

All inspection data collected with LRTK is automatically synchronized to the cloud on-site. The images here are of scan and photo data uploaded in real time to a cloud project. This eliminates the need to copy photos via USB or send files by email after returning to the office.

Cloud sharing makes information exchange within inspection teams and with stakeholders smooth. For example, while on-site inspectors are collecting data, an in-office structural engineer can view the cloud data and provide guidance by phone—enabling real-time collaboration. Situations that historically required taking results back to discuss can now be understood by everyone instantly, speeding up decision-making.

As data accumulates in the cloud, centralized record management is achieved. Past inspection histories, reports, and point cloud models are organized and stored by project, so desired information can be retrieved easily later. Think of it as an archive of each building in the cloud, which is far easier to manage than paper ledgers or folders on a local PC.

Moreover, using the cloud makes explaining findings to owners or clients quick. For example, you can share a cloud-based report page with the owner immediately after inspection and allow them to view the 3D model and photos. Clients who are remote can check inspection results on their own smartphone or PC, making it easy to convey information even when face-to-face explanations are difficult.

Automate Report Generation to Streamline Reporting Tasks

After inspection work is complete, the remaining task is report creation, which includes organizing photos, creating drawings, and writing observations. Traditionally, reporting took a lot of time and effort. LRTK significantly improves this process as well.

Using data captured by LRTK, inspection reports can be automatically generated. For example, from the cloud management interface you can press a “Create Report” button to output a summary form of inspection results and a detailed photo ledger. Because photos are already linked with coordinates and annotations, lists of cracks and markings on façade elevations are reflected automatically. There is no need to manually adjust layouts or assign numbers to photos—reports that span tens of pages can be completed in a short time.

Automatically generated forms can present crack locations and lengths, deterioration types, and other organized information, resulting in clear and comprehensive reports. The elimination of omissions or inconsistencies among inspectors and formats ensures consistently high-quality output. This reduces overtime caused by report creation and allows inspectors to spend more time on tasks that truly require attention, such as analyzing inspection results and planning repairs.

Since the reports are digitized, they can be shared and stored in the cloud as-is, eliminating the need for printed copies and postal submission. While exporting PDFs and emailing them is possible when needed, making the reports viewable in the cloud often provides easier access to the latest information and search functionality. Streamlining the entire reporting flow allows for faster consideration of post-inspection measures and quicker reporting to owners.

Useful for Periodic Inspections of Used Buildings, Pre-Sale Surveys, and Repair Planning

The efficiency improvements LRTK brings to exterior inspections are valuable in many scenarios. Examples of potential applications include:

• Periodic inspections of used buildings: For aging office buildings and condominiums, regular exterior inspections are indispensable for safety management. Introducing LRTK enables efficient inspections of large buildings with a small team and preserves objective records as photos and point cloud data as assets. Accumulating data at each inspection makes it possible to track deterioration trends over the long term and provides material for planning systematic repairs.

• Pre-sale property surveys: When buying or selling used properties, understanding the building’s condition is important to both buyers and sellers. Inspecting the façade with LRTK lets you present detailed, visualized data on cracks and exterior material conditions. Convincing 3D models and geotagged photos, more persuasive than traditional survey reports, can reassure buyers or demonstrate a seller’s proper maintenance. This contributes to preventing disputes and aiding value assessment in real estate transactions.

• Repair planning: LRTK data is also powerful when planning large-scale repairs or targeted restoration. Point cloud models obtained during inspection reflect the positions and extents of deterioration, allowing a visual grasp of which parts require what degree of repair. Objective data showing areas with concentrated cracks or many tiles lifting clarifies prioritization and calculates work scopes. Additionally, comparing before-and-after data makes it easy to verify repair effectiveness.

Thus, LRTK supports exterior inspection operations across a wide range of uses—from routine building maintenance and transaction-time surveys to future-oriented repair planning. It can be used regardless of building scale, from detached houses to high-rise condominiums, commercial buildings, and schools or other public facilities. For construction contractors, property management companies, and architects, LRTK has the potential to become a new standard.

Conclusion: Streamline Exterior Inspections and Simple Surveying with LRTK

We have reviewed the benefits of LRTK, which improves the efficiency and accuracy of exterior wall inspections. Tasks that tended to require a large workforce can be digitized with LRTK, enabling small teams to achieve high-quality results in shorter timeframes. Data that records every crack accurately will be greatly useful for building safety management and preserving asset value.

Moreover, LRTK is not limited to façade inspections; it can also be applied to simple surveying and layout tasks. The coordinate guidance function, which combines high-precision GNSS and AR technologies, allows on-site marking of specified points from drawings using only a smartphone. Its versatility—handling site measurements, elevation checks, and equipment layout positioning—makes it attractive for meeting surveying needs that arise on construction sites.

From streamlining exterior inspections to simple surveying, LRTK can be a powerful partner in advancing DX in building management and construction. If you feel there are challenges in your current exterior inspection workflows, consider adopting LRTK. Bringing the latest technology to the field can dramatically improve safety and work efficiency and contribute to enhancing your building’s value.