Monitoring cracks on inaccessible facades
In such configurations, the installation of access equipment is required for each observation and limits the regularity of crack monitoring.
When facade cracks are not accessible from the ground
Some cracks in a building affect external walls located at height, beyond the reach of direct observation from the ground. These cracks may be located on gable walls, upper-floor facades, balconies, or slab edges, meaning parts of the structure that cannot be accessed without specific access equipment.
In these situations, visual observation from the ground generally does not allow an accurate assessment of crack opening or its variations over time. However, close inspection, which is necessary for measurement operations, requires direct access to the affected area.
The inaccessibility of these areas therefore requires, for each observation or measurement operation, the installation of access systems adapted to the height and configuration of the facade. This constraint determines not only the possibility of intervention but also the frequency at which cracks can be observed and measured.
Access to facade cracks: methods and working conditions
Accessing a crack located on an external building wall at height requires the installation of access equipment allowing direct work on the facade. Depending on the height of the structure, the facade configuration and the building environment, access may be provided by scaffolding, aerial work platforms, or rope access technicians.
The choice of access method depends in particular on:
- The height of the area to be reached;
- The configuration of the facade;
- The presence of balconies, projections or overhanging elements;
- The presence of obstacles or constraints at ground level;
- The occupancy conditions of the premises.
These interventions are governed by regulations related to working at height and must be prepared before any work on the facade.
The installation of access systems determines both the safety of the intervention and its technical feasibility.
facade crack monitoring and repeated measurements
Monitoring a crack requires the ability to carry out successive measurements. When the crack is located on an inaccessible facade, the repetition of these measurements remains directly dependent on the ability to reinstall the access equipment.
The interval between two observations depends on the accessibility conditions of the facade and on the availability of equipment for working at height.
Measurements may therefore be spaced due to constraints, without corresponding to the monitoring interval initially planned.
Monitoring therefore relies on measurement series whose frequency and regularity are determined by the accessibility of the facade.
Contribution of connected gauges for cracks on inaccessible facades
Saugnac Jauges designs and manufactures a range of connected gauges intended for monitoring cracks and structural movements, particularly suited to situations where facade access is constrained or only occasional.
For cracks on building facades that cannot be accessed from the ground, the use of connected gauges makes it possible to monitor crack evolution using measurement data collected remotely.
How are connected gauges installed and operated on an inaccessible facade?
The installation of a connected gauge takes place during a one-off intervention on the facade, using appropriate access equipment. Once installed, the device remains in place and automatically records measurements that are transmitted remotely at defined intervals.
A distinction is therefore made between the installation phase, which depends on access to the facade, and the monitoring phase, which no longer requires any physical return to the monitored area.
Which gauge allows direct monitoring of a crack on an inaccessible facade?
The direct monitoring of crack opening on an inaccessible facade can be carried out using the R1 connected crack monitor, designed to measure and record variations in crack opening over time.
In some situations, crack monitoring may be complemented by other measurements, although these do not constitute direct monitoring of crack opening.
The R5 connected inclinometer gauge, dedicated to inclination monitoring, can be used to observe the evolution of the inclination of a facade element or a structure.
The R2 connected crack monitor is an alternative when the movements to be measured are larger. Equipped with a remote linear sensor, it makes it possible to monitor crack opening with a measurement range of up to 100 mm, which expands instrumentation possibilities compared with the R1. It also features a Follow+ mode, which can be activated remotely to temporarily increase the measurement frequency and obtain finer monitoring during critical phases or rapid movements.
How is measurement data used?
Measurements are recorded automatically and then transmitted to the monitoring application, where they can be viewed as graphs and historical records. This visualization facilitates the analysis of movement evolution and the detection of potential acceleration or stabilization phases.
The R1, R2 and R5 gauges also integrate temperature and ambient humidity sensors. These environmental data help to better interpret the measured variations, for example by identifying the influence of thermal cycles or climatic conditions on the behaviour of the crack or the monitored structure.
Building cracks, danger and concern: the role of measurement
The notions of danger or concern associated with a crack in a building are based on observation. Comparing successive measurements makes it possible to objectively assess variations in crack opening, without replacing a diagnosis or structural analysis. Instrumented monitoring aims solely to provide measurement data on this evolution, independently of any conclusion regarding the stability of the structure.