Why It Matters
All buildings move!
New gaps and cracks appear over time, but how much is too much?
Movement Over Time
There are typically three components to building movement; thermal, geotechnical, and structural.
Each of these occurs on a different time scale; years, months, weeks, or even hours. Simple analog gauges with ad hoc manual measurement times often mask short term movement that has longer term consequences.
As an example, a measurement taken in the heat of the afternoon in April might compare similarly to a measurement taken in the early morning 3 months later in July. However, comparing full day movement cycles could reveal a noticeable change in the crack not only throughout the day but also across the 3 months.
Only by measuring frequently and consistently over time can these individual effects be put into proper context.
Expert Studies Show
Structural Health Data Systems
Continuous high-fidelity data ensures better understanding of building effects and provides ongoing peace of mind for building owners
The TOP 13 Advantages of Automated Monitoring
The advantages of automated electronic crack monitoring over traditional static analog gauges are numerous and, in the end, economically superior. This paper covers the great benefits of electronic devices and for a full explanation of the cost savings potential, Please see our article on the economic benefit of automatic crack monitoring:
Historical Structures benefit from long-term monitoring
We appreciate old things of significance, historic relics and memories that spark reflection of where we come from, events that shaped our culture, and how those before us lived and persevered. Preservation of these records against degradation is important and valued.
Why use automated electronic crack monitoring
There are several noteworthy advantages of using an electronic automated crack monitor over traditional static gauges ( metal or plastic ). See our article on the advantages of an electronic crack monitor for a complete list.
As one architect stated about visible cracks:
“Your house isn’t going to roll over – watch it over time to see if you’ve got a real issue.”
Sometimes a crack is only just a crack.
Motion Marker Specifications
The device shown is battery-operated and designed for multi-year operation. The device wakes hourly, measures the growth or shrinkage of a crack in both X and Y directions with 0.2 mm accuracy, reads the ambient temperature, time stamps the record, and transmits the data to a web-based application for capture, analysis, reporting, and real time notification as required.
For reference, 0.2 mm is about the thickness of 2 sheets of common copy paper.
Good Structural Data Matters
In Dec 2017 a residential homeowner noticed a new crack in the brick of their home. This was the first crack ever seen in the end wall of the home which had been built in 1978.
Though not a huge crack, it ran down most of the wall and split both bricks and mortar as shown in the images below.
Because this was disconcerting enough to warrant watching, in January 2018, the homeowner installed a Motion Marker crack monitor from Structural Health Data Systems and immediately began getting detailed data on the short term and long-term movements of the crack.
Although Structural Health Data Systems provides a simple web-based interface to review, plot, and analyze hourly data in many ways, most building owners only want to know if they have an issue that requires action. and the User can establish limits for concern and SHDS can provide automatic email notifications when the limits are exceeded. Data shows how limits can be established.
Charts can show crack movement data over time from the device shown above. From left to right, the charts show raw data in mm of movement over 10 days, predicted movement from the applied thermal data, and an overlay of the two curves.
What is seen from this data is that a swing of 1.4 mm of movement is explained from just thermal effects. The short-term variation is entirely predicted – the structure is not moving outside of normal thermal effects. (The ambient temperature went from 6 to 77 deg F over this time period.)
By comparison, using a manual gauge with 0.5mm resolution, a foundation repair company could have “demonstrated” that there was 1-2 mm of movement per week, raising the need to complete an unnecessary repair.