A method and arrangement for drying a water damaged floor structure having a ventilated isolating layer below a concrete layer extending throughout an enclosed space, and the enclosed space having a tiled flooring over the concrete layer. An outlet opening is provided into the floor structure and to the isolating layer outside of an end of the enclosed space, the tiled flooring is heated by a heating source, and ambient air drawn by a suction source through the isolating layer and out of the outlet opening.

A dehumidifier apparatus comprising a sorption dehumidifier (10) having a process air inlet (12), a dry air outlet (22) and a wet air outlet (16), According to the invention the apparatus comprises a heat exchanger (50) located at said outlets (16, 22) for heating dry air (18) exiting the dry air outlet (22) by wet air exiting the wet air outlet (16); and a heat insulation (60) enclosing the dehumidifier (10) and the heat exchanger (50).

A hand-portable drying apparatus and method for use in a damp or waterlogged room, the apparatus including a housing having a carrying handle, the housing containing first and second airflow ducts arranged generally parallel to each other and having respective air inlet and air outlet ends, the apparatus further including means to force air through the ducts and to selectively heat it in at least one of the ducts, and valve means within the housing to selectively direct air from the first duct to the second duct whereby to move air from within the room received by the first duct back to the room via the second duct or to expel air from the room via the first duct to outside the room and draw in fresh air from outside the room via the second duct.

A hand-portable drying apparatus and method for use in a damp or waterlogged room, the apparatus including a housing having a carrying handle, the housing containing first and second airflow ducts arranged generally parallel to each other and having respective air inlet and air outlet ends, the apparatus further including means to force air through the ducts and to selectively heat it in at least one of the ducts, and valve means within the housing to selectively direct air from the first duct to the second duct whereby to move air from within the room received by the first duct back to the room via the second duct or to expel air from the room via the first duct to outside the room and draw in fresh air from outside the room via the second duct.