Abstract: A sealable frame structure for a closable opening, such as a doorway, comprises a sub-frame (1) which is adapted to be built into an opening in a wall and a frame shroud (7) adapted to be fixed to the sub-frame. The sub-frame is U-shaped in cross-section and its web is provided with a series of holes (2) by means of which the sub-frame may be secured to the wall by anchor fixings. One limb (3) of the U-shaped frame is provided with a series of holes (4) for the reception of studs (8) welded on the frame shroud (7). A strip (9) of stainless steel or like material is secured to the other limb (5) of the subframe by means of bolts (10) and nuts (11) and the frame shroud (7) is secured to the strip (9) by screws (12) which engage in drilled and tapped holes (13) in a strip (14) of steel. An extruded strip (15) of silicone rubber having a protruding profile (16) is fitted over an edge of the strip (9) and forms a seal with the edge of a door closing the doorway.