and are supported by the interior surfaces of the 34 l 34 of the angle irons 42 referring simultaneously to fig2 and 4 downward telescoping motion of the drop floor 34 is provided by a drop floor mounting means preferably comprising series of six slide sleeves 48 the slide sleeves 48 being welded to the inwardly facing surfaces of 34 i 34 beams 14 the slide sleeves 48 are preferably fabricated from square structural tubing and are fitted for slidably receiving a series of six slide shafts 50 which are also preferably fabricated from square tubing slide shafts 50 are preferably welded to the inwardly facing surfaces of the vertical flanges 44 of the angle irons 42 both the slide sleeves 48 and the slide shafts 50 are situated so that they lie within the insulation space of the side walls of the lower split level room 32 referring to fig1 depicting the under surface of the mobile home 1 34 i 34 beams 14 which extend along the left and right sides of the drop floor 34 overlap and are welded to 34 i 34 beams 12 at overlap joints 52 by overlapping 34 i 34 beams 14 and 34 i 34 beams 12 rather than utilizing a continuous 34 i 34 beam along the full length of the mobile home 1 the lateral dimension of the drop floor 34 may be substantially equal to the lateral dimension of the main floor 54 the main floor 54 is preferably composed of an upper layer of composite board 56 which overlies a series of two inch by.