How is an elevation certificate prepared?

Our survey crew visits the site and take measurements to determine the elevations of the following: the building floor; the ground next to the building; and other features such as utilities and decks. The crew will need access to the building to document the type, number and location of existing flood vents and to take measurements. The flood zone is then indicated on the Flood Insurance Rate Map, and the information is compiled on a certificate (the exact information shown on the certificate varies depending on the type of building).

Please note: the elevations shown are based on a reference datum described by the U.S. National Geodetic Survey. Most older elevation certificates are based on NGVD29 (National Geodetic Vertical Datum of 1929), while most newer certificates are based on NAVD88 (North American Vertical Datum of 1988). The same point will have different numbers for elevation under the two systems. Other documents may be based on other reference elevations and may not be directly comparable.