A device (1) for applying a coating of hardenable plastic to an inner side of a wall of a tubular construction, for example a sewage pipe, includes a supply chamber (3) for containing a hardenable plastic, a delivery head (2) including an outlet (5) for letting out the hardenable plastic from the delivery head (2), and a pump (11) for transporting the hardenable plastic from the supply chamber (3) to the outlet (5). During use, the outlet (5) is positioned at various angular positions with respect to a rotation axis (40), so that the entire circumference of the inner side of the wall of the tubular construction can be provided with the hardenable plastics coating. The supply chamber (3) includes a flexible wall for optimal maneuverability of the device (1), whereby broad application of the device (1) is possible.