High precision geometric levelling

Execution of altimetric survey using sub millimetric precision optical level and invar staff. The altimetric survey is carried out to define in detail the altimetry of a site, internal or external to a building, and is particularly useful in defining a framework of differential settlements corresponding to a flooring of a historic building, or in acting as a monitoring activity for subsidence assessment if re-executed at pre-established time intervals. Finally, this measurement method is carried out in the event of load tests when the intrados of ​​the floor subjected to load is not accessible, and one wishes to read the absolute deflections by operating only from the extrados. When altimetric monitoring is carried out, it is good practice to take as a measurement reference a point outside the range of potential vertical displacements, considered as a fixed point, to compensate for any measurement errors.