A method of testing a flat construction element with regard to resistance to a pressure effect, with the following process steps: a) the construction element is installed in a support frame in a force-transmitting manner; b) the support frame provided with the construction element is assembled at or in front of a wall in such a way that a pressure chamber delimited with respect to the surroundings is formed between the frame legs of the support frame, the construction element and the wall; c) at least one pressure container is filled with a compressible fluid until a pressure p B prevails in the pressure container, said pressure being greater than an ambient pressure P u; d) at least one blocking element of a blocking device is transferred from a blocking position into an open position, as a result of which a free connection cross-section is created from the pressure container to the pressure chamber, as a result of which an excess pressure of at least 0.1 bar, preferably at least 0.2 bar, more preferably of 0.5 bar, more preferably of 1.0 bar and even more preferably of 2.0 bar acting on the construction element is in turn generated in the pressure chamber in a loading plane defined by the construction element, wherein e) the transfer of the blocking element of the blocking device from the closed position into the open position takes place in a non-destructive and reversible manner, wherein the blocking device is arranged in at least one connecting line between the pressure chamber and the pressure container; f) fluid is drained from the pressure chamber through at least one relief opening during the pressure effect of the fluid on the construction element, characterised in that the at least one relief opening is formed by an optionally opening or closing relief valve, which is constituted as a non-return valve in the form of a flap valve, which preferably permits only a pressure relief of the pressure chamber. a) the construction element is installed in a support frame in a force-transmitting manner; b) the support frame provided with the construction element is assembled at or in front of a wall in such a way that a pressure chamber delimited with respect to the surroundings is formed between the frame legs of the support frame, the construction element and the wall; c) at least one pressure container is filled with a compressible fluid until a pressure p B prevails in the pressure container, said pressure being greater than an ambient pressure P u; d) at least one blocking element of a blocking device is transferred from a blocking position into an open position, as a result of which a free connection cross-section is created from the pressure container to the pressure chamber, as a result of which an excess pressure of at least 0.1 bar, preferably at least 0.2 bar, more preferably of 0.5 bar, more preferably of 1.0 bar and even more preferably of 2.0 bar acting on the construction element is in turn generated in the pressure chamber in a loading plane defined by the construction element, wherein e) the transfer of the blocking element of the blocking device from the closed position into the open position takes place in a non-destructive and reversible manner, wherein the blocking device is arranged in at least one connecting line between the pressure chamber and the pressure container; f) fluid is drained from the pressure chamber through at least one relief opening during the pressure effect of the fluid on the construction element,