Yes, in order to take into account an increase in moisture content it is necessary to incorporate an expansion gap. For tongue & groove boards a gap should be provided around the perimeter of the floor to any upstands or abutting construction to allow for possible expansion of the decking.
An expansion gap of 10 mm or 2 mm per metre run of the floor, whichever is greater, should be left against all walls. Intermediate gaps (min. 10 mm) should be incorporated for floors in excess of 10 m long e.g. corridors. The gaps should be finished with a compressible filler or proprietary movement joint cover.
For further information, please refer to the EGGER Advanced Fitting Guide here.