Exterior walls gradually deteriorate from daily wind, rain, and earthquakes, leading to issues such as cracks and tiles lifting or falling off. Exterior wall inspection is indispensable for early detection of such deterioration to ensure safety and protect the asset value of buildings. However, performing exterior wall inspections by conventional methods—from single-family homes to apartments and large public facilities—has been a labor- and time-intensive task. This article introduces a cutting-edge tool that streamlines those inspections: LRTK. Using smartphone-based AR (augmented reality) for crack verification and coordinate-tagged photos for precise record keeping, we explain in detail how exterior wall inspection workflows can be transformed.

The Importance of Exterior Wall Inspections and Traditional Challenges

If cracks or tile detachment are left unaddressed, they can lead to serious risks such as water ingress causing internal corrosion or falling facade materials resulting in accidents. There have been incidents where parts of aged exterior walls fell and injured passersby, so building managers are required to conduct regular inspections and timely repairs. Therefore, regular inspections are recommended for older buildings, and it is common practice to have specialists survey a property before a sale to understand its condition.

However, traditional exterior wall inspections have faced the following challenges:

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

• Cumbersome record-keeping: Inspection results were commonly recorded manually on drawings and ledgers. For example, a two-person team might have one person perform tapping and visual checks while the other marks the drawings or takes photos on site. The information would be compiled into a report later, but it was easy to misidentify photo locations or make transcription errors onto drawings, making record management cumbersome.

• Risk of oversight: Reliance on human sight and manual methods inevitably leaves room for missed spots or record omissions. Thoroughly checking the entire exterior is difficult, and there were cases where recorded crack locations became untraceable later.

• Difficult to compare over time: Even if one wanted to compare with the previous inspection, it was necessary to pull out past photos and notes and manually cross-check them, making analysis of long-term changes difficult. As a result, prioritizing repairs and assessing deterioration progression took considerable time.

Due to these issues, improving efficiency and accuracy in exterior wall inspections has been a long-standing goal. Amid expectations for a DX (digital transformation) of exterior wall inspections using digital technologies, a versatile smartphone-mounted surveying and inspection tool called “LRTK” has emerged.

Digitalizing and Streamlining Exterior Wall Inspections with LRTK

LRTK is a small device attached to a smartphone or tablet that consolidates tasks that previously required separate equipment and processes into a single unit. By combining a high-precision GNSS (GPS) receiver with the smartphone’s built-in LiDAR scanner and other sensors, LRTK enables on-site positioning, measurement, and recording to be completed digitally. Using LRTK transforms formerly analog exterior wall inspection workflows.

Key features LRTK provides include:

• High-precision 3D point cloud scanning: By waving the smartphone to scan the exterior wall surface, you can capture the wall’s shape as high-precision point cloud data composed of countless points. This instantly yields a digital 3D model of the building’s exterior on site.

• AR visualization of deterioration: Using the captured 3D model and location data, virtual information is overlaid on the real building within the smartphone display. This allows cracks and other deterioration to be displayed in AR on site for intuitive verification and recording.

• Coordinate-tagged photos: When you take a photo, the shooting location’s coordinates (latitude, longitude, and height) and the camera’s orientation are automatically recorded. Each photo is tagged with position information so that even a large 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 the spot and can be shared in real time with office PCs and stakeholders. The whole team can view the latest inspection data, making information transfer 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 at the press of a button, greatly streamlining reporting tasks.

In the following sections, we’ll look at how these features concretely change exterior wall inspections.

Record the Entire Condition of the Exterior with High-Precision 3D Point Cloud Scans

One of LRTK’s major strengths is capturing the current condition via high-precision 3D point cloud scanning. With a dedicated high-precision GPS and the smartphone’s LiDAR, you can digitally record the exterior wall’s shape down to the smallest details. Whereas conventional work required taking photos of each section while cross-checking drawings, with LRTK you simply walk along the wall while holding the smartphone to complete the process.

The point cloud data obtained by scanning is a three-dimensional model representing the wall’s positions and irregularities as countless points. For example, by moving the LRTK along the facade, you obtain data that captures the entire wall’s shape in millimeter-level detail, including areas with cracks or detached finishing materials. Because the point cloud is highly accurate and minimally distorted, it serves as a reliable base for later measurements or comparisons with drawings.

Having a digital 3D model means that areas missed on site can be reviewed in detail back at the office. If you scan broad areas of the facade at once, there’s no need to worry about “forgetting to take a photo of that spot.” Storing the entire building as a point cloud also aids in comparisons over time. If you acquire a new point cloud at the next inspection, differences from the previous data can visualize crack expansion or facade deformation, providing basis for judging deterioration progression.

Additionally, LRTK’s GPS offers centimeter-level positioning accuracy, so the captured point cloud model is tied to real-world coordinates as a high-precision map. This enables integrated condition records that include positional relationships around the building and height references. Tasks that were previously difficult—such as checking overall building distortion or creating elevation drawings—become easy using scan data.

Intuitively Identify Deterioration and Cracks with AR Display

LRTK leverages the scanned 3D model and current positioning to provide on-site AR displays. When you view the building through your smartphone, virtual information is overlaid on the screen. For example, when you discover a crack, you can tap the screen to place a marker that will appear stuck to the corresponding spot on the wall in AR. This lets you digitally mark deterioration on the spot and review it later.

AR displays are powerful not only for recording but also for intuitive verification. While inspecting, simply scanning the smartphone screen makes marked crack locations visually stand out, helping to prevent inspection omissions. Because you can instantly see “what has been checked” and “what remains to be inspected,” you can efficiently inspect wide facades without missing areas.

AR is also effective for team information sharing. When another technician visits the site later, they can point their smartphone and see previously marked deterioration in AR, making it easy to identify the same locations. This is useful when repair crews need to understand deterioration beforehand. The feeling of digital information being attached to the real wall closes the gap where “photos were unclear but it was obvious on site.”

LRTK’s AR enables stable displays with minimal positional drift thanks to high-precision positioning technology. Ordinary smartphone AR alone can gradually drift during long use, but LRTK corrects positions via GPS, reducing marker displacement relative to the real world. This allows confident continued use of AR and contributes to accurate understanding of positional relationships.

Accurate Inspection Record Management with Coordinate-Tagged Photos

Inspections involve taking many photos, and with LRTK every photo automatically receives coordinate information, making record management dramatically more accurate and simple. Traditionally, you had to attach notes to each photo like “north face, east side, floor X crack” or number drawings and match them up. With LRTK, simply pressing the shutter stores data indicating where the photo was taken.

Specifically, when you take a photo with LRTK’s capture app, the system automatically records coordinates such as latitude, longitude, and height, the timestamp, and even the camera’s orientation (azimuth). For example, if you find a crack on the east face of a ten-story apartment and photograph it, the photo is saved with information associating it to “a crack located at X meters height on the east face.”

The advantage of coordinate-tagged photos is that the photo’s location is immediately clear even later on. Even when handling large volumes of photos, you can plot photo locations on a map or drawing without guessing from file names or notes. You can display thumbnails with a map in the management interface, and clicking a photo can show a marker at the corresponding location—making it a well-organized database of inspection records.

Because photos contain position information, tracking changes over time is also easy. If you photograph the same coordinates in a later inspection, you can perform precise before-and-after comparisons of exactly the same spot. This allows accurate assessment of whether a crack has expanded or new deterioration has appeared, aiding timely and appropriate repair decisions.

Cloud Syncing for Instant Sharing of Inspection Data

All inspection data collected with LRTK is automatically synchronized to the cloud on site. Scans and photos taken with your smartphone are uploaded in real time to the cloud project. This eliminates the need to return to the office to copy photos via USB or send files by email.

Cloud sharing smooths information exchange within the inspection team and with stakeholders. For example, while fieldwork is ongoing, an office-based structural engineer can view the cloud data and give instructions over the phone about points of concern—enabling real-time collaboration. Cases that previously required bringing results back for consultation can now be handled immediately by everyone viewing the same data, speeding up decision-making.

With data accumulated in the cloud, centralized record management becomes possible. Past inspection histories, reports, and point cloud models are organized and stored per project so you can easily retrieve information later. Think of it as having an archive for each building in the cloud—far easier to manage than paper ledgers or local folders on a PC.

Furthermore, via the cloud you can quickly explain findings to owners or clients. For instance, you can immediately share a cloud report page after inspection that allows viewing the 3D model and photos. Clients in remote locations can check results on their smartphone or PC, making it easy to communicate even when face-to-face explanations are difficult.

Streamline Reporting with Automatic Inspection Report Generation

After inspection work, the next time-consuming task is preparing the inspection report, including organizing photos, creating drawings, and writing observations. Traditionally, report preparation demanded significant time and effort. LRTK greatly streamlines this process too.

Using data captured by LRTK, you can automatically generate inspection reports. For example, with a “Create Report” button in the cloud management interface, you can output summary forms and detailed photo catalogs documenting the inspection results. Because photos already carry coordinates and annotations, crack lists and markings on elevation diagrams are automatically reflected. There is no need for manual layout adjustments or numbering photos for matching—even reports running dozens of pages can be completed quickly.

Automatically generated forms can present crack positions, lengths, and deterioration types in an organized manner, producing clear and comprehensive reports. This eliminates omissions based on individual reporters or inconsistencies in format, ensuring consistently high-quality outputs. As a result, staff spend less time working overtime on report preparation and have more time to focus on analyzing inspection results and planning repairs, which are their core tasks.

Electronic reports can be shared and stored in the cloud as-is, removing the need to print and mail bound paper copies. While PDFs can be exported and emailed if necessary, keeping reports viewable in the cloud usually makes access to the latest information and searching easier. Streamlining the entire flow through to reporting also speeds up follow-up actions and owner communications after inspections.

Useful for Regular Inspections of Older Buildings, Pre-Sale Surveys, and Repair Planning

The efficiency gains from LRTK in exterior wall inspections are useful in many scenarios. Examples of expected use cases include:

• Regular inspections of older buildings: For aging office buildings and apartment complexes, regular exterior wall inspections are essential for safety management. Introducing LRTK enables efficient inspections by small teams even for large buildings and leaves objective records in the form of photos and point cloud data. As data accumulates with each inspection, long-term deterioration trends can be tracked and used to plan repairs systematically.

• Pre-sale surveys for property transactions: When buying or selling used properties, understanding the building’s condition is important for both parties. LRTK enables visualization of cracks and facade conditions through detailed data. Persuasive 3D models and coordinate-tagged photos provide buyers with reassurance and give sellers a way to demonstrate proper maintenance. This contributes to preventing disputes in real estate transactions and supports property valuation.

• Repair planning: LRTK data is powerful when planning large-scale renovation works or partial repairs. Point cloud models from inspections reflect the positions and extents of deterioration, allowing clear visualization of which parts need repair and to what degree. Objective data showing areas with concentrated cracks or many lifted tiles makes prioritization and calculation of repair scope straightforward. Comparing data before and after work also makes it easy to verify repair effectiveness.

In this way, LRTK supports a wide range of exterior wall inspection tasks—from routine building maintenance and transaction surveys to forward-looking repair planning. It is applicable regardless of building type or scale, from single-family homes to high-rise apartments, commercial buildings, and schools. LRTK has the potential to become a new standard for construction companies, housing management firms, and architects.

Conclusion: Streamline Exterior Wall Inspections and Simple Surveying with LRTK

We have reviewed the benefits of LRTK for improving the efficiency and accuracy of exterior wall inspections. Tasks that traditionally relied on manpower can be digitally transformed with LRTK, enabling small teams to produce high-quality results in much less time. Data that records each crack precisely will greatly aid building safety management and asset value preservation.

Moreover, LRTK is not limited to exterior wall inspections; it can also be applied to simple surveying and layout marking. Its coordinate-guidance function, which combines high-precision GNSS and AR technology, lets you accurately mark points specified on drawings in the field using a smartphone. From measuring site dimensions and checking elevation differences to positioning equipment layouts, LRTK’s versatility in addressing surveying needs on construction and job sites is a major advantage.

From streamlining facade inspections to enabling simple surveying, LRTK is a powerful partner for driving DX in building management and construction. If you currently face challenges in your exterior wall inspection workflow, consider introducing LRTK. Bringing the latest technologies to the field can dramatically improve safety and operational efficiency, and help enhance the value of your buildings.