G1 Gauge

121,20 w/o VAT per box 10 units

G1 Gauge is recommended for measuring crack evolution in a single plane. This the standard gauge for inside or outside.

Delivered with a black box of 10 gauges, 1 pen and detailed notice.

Table of content

Technical characteristics
Fixing the gauge
Crack in angle
Gauge protection
Reading the gauge
Exemple of use
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Technical characteristics

  • Reading the crack evolution to 1/10th of a mm using a vernier
  • White, in extruded PVC. Sliding tongue in Lexan.
  • Foldable plastic angle bar inserted into a slotted hold (patented system)

Foldable angle bar with G1 gauge

  • Weather-resistant (for outside or wet building)
  • Size : 140 X 40 mm, total depth: 3 mm,
    • thickness of plate = 0,7 mm
    • thickness of sliding tongue = 0,5 mm
  • Weight 4g
  • Traction force in the order of 25g
  • Coefficient of linear expansion = 7.10-5

Fixing G1 gauge with plugs and screws

By gluing: the gauge can be fixed easily and fastly usin double-sides self-adhesive tabs. It is possible to strengthen the sticking using epoxy glue with rapid hardening in twin syringue.

By mechanical fixation: G1 family gauges are supplied ready drilled with two Ø4 mm holes. These holes facilitate fixing by mechanical means using plugs and screws on difficult structures where self-adhesion and sticking are not possible.

We recommend gluing the gauges to the structure wherever the condition of its surface does not allow the use of self-adhesive tabs.
If gluing is also impossible, we advise fixing with plugs and screws. An impact anchors kit ready to use is available for order.


Result of fixing with anchors and screws:

G1 Gauge fixed with mechanical screws


Measuring the variation in a crack in a vertical or horizontal internal angle

It is possible to fix the gauge in angle : G1 family gauges are supplied with a foldable plastic angle bar or an aluminium angle bar can be ordered.

Jauge G1 posée en angle

The internal corner is a 90° angle. A G1 gauge is used with a plastic angle bar:

The internal corner is irregular. A G1 gauge is used with a plastic angle bar and an attachment plate:

A G1 gauge is used in an internal vertical corner with an aluminium angle bar fixed with a plug and screw:

A G1 gauge is used on a crack on the edge of an external corner with an aluminium angle bar:

Gauge protection

We recommend that gauges used in public places -schools, shops, streets – should be protected.
The protective cover can also be fixed with plugs and screws. Two types of protection are available: standard protection et high protection anti-UV.

Protection Jauge G1 Saugnac

Reading the gauge

The upper section is graduated in mm from 0 to 30: this is the measurement scale. The lower section moves: this is the 1/10th mm vernier (10 divisions of the vernier correspond to 9 mm on the measurement scale).


Reading a measurement with a decimal (example: gauge G1. N°3):
The pointer of the vernier is between two graduations of the measurement scale. Example: between 13 and 14.
a) Reading the millimeters:

The number of mm corresponds to the graduation to the left of the pointer of the vernier: in this case that is 13.

b)  Reading the decimal:

Find the line on the vernier which is exactly opposite a line on the measurement scale. In this example with gauge N°3, graduation 8 on the vernier is in line with graduation 21 on the measurement scale.
The decimal reading is thus 8/10th of a mm. The overall reading is therefore 138/10th of a mm. Reading: 138/10th of a mm

Even simpler to read and more accurate:    G1+ gauge with “digital” readout.

Example of use

Example of monitoring the variations in cracksin a construction built on clay ground reacting to variations in water content.

After an observation period which confirmed that the cracks were opening and closing, it was decided to carry out a draining operation and build a walkway around the periphery. The structure stabilized within the six months following the work..

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