the preferred embodiments illustrated are not intended to be exhaustive or to limit the invention to the precise forms disclosed . they are chosen and described in order to best explain the principles of the invention and its applications and practical uses to thereby enable others skilled in the art to utilize the invention . the door frame assembly 8 of this invention , is shown in fig1 - 4 and includes a three - sided outer frame 10 , and a corresponding wooden inner frame 12 . a threshold of conventional design may be used with assembly 8 . the outer frame 10 is preferably made of an extruded material , such as metal or plastic , and is of the uniform cross section , shown in fig3 and 4 . outer frame 10 is configured to receive the inner frame 12 which fits snugly into it . inner frame 12 , is preferably secured to the outer frame 10 by screws 17 and 18 or other attachment means . screws 17 are turned through inner frame 12 and anchor into inturned return flange 21 of the outer frame 10 . screws 18 are driven through one wall 11 of a u - shaped portion 13 of the outer frame 10 and are anchored in inner frame 12 . screws 17 and 18 remain hidden from view when the door frame assembly is in position against the existing wall structure 20 which defines the door opening . the door frame assembly 8 is secured to the sides and top of the door opening in an existing structure 20 by use of screws 22 or other means turned through an outturned flange or wall 23 of portion 13 of the outer frame 10 and anchored in the existing structure 20 . wall 23 may terminate in a longitudinal lip 24 , which preferably extends perpendicularly outwardly from the margin thereof . a flange 25 may project substantially perpendicularly from wall 11 and may terminate in a groove part 26 . the inturned return flange 21 of the outer frame 10 provides a stop for the door 34 and is provided with a u - shaped longitudinal channel 30 whose mouth is defined by inturned ribs 31 . channel 30 receives with a snap fit a molded enlargement 32 or strip 33 , preferably formed of rubber or other suitable flexible material , which is engaged by the margin of door 34 and serves as a seal or weather strip . the walls 11 and 23 may be optionally covered by a decorative member 14 , which is generally l - shaped . decorative member 14 includes a longitudinal marginal u - shaped part 27 , which fits around the lip 24 , and in an opposite longitudinal marginal hook part 28 which anchors in groove part 26 . decorative member 14 is retained in place by u - shaped margin 27 straddling lip 24 and the snap interlock of hook part 28 with groove 26 , thereby covering screws 22 turned into the underlying structure 20 . when the door frame assembly is anchored to the door opening structure 20 and optional decorative members 14 are applied , no means of attachment to the opening structure is visible . the frame assembly can be easily adjusted within the existing door opening by the simple removal and replacement of screws 22 . a second embodiment of this invention describes a window frame assembly 40 which is shown in fig5 - 7 . frame assembly 40 includes an outer frame member 42 , inner frame member 44 and optional cover member 46 . the outer frame 42 is made of extruded metal or plastic material and is configured to receive inner frame 44 , which fits snugly into it . frame assembly 40 is secured to the sides of the window opening in underlying structure 80 by fasteners , such as screws 62 . screws 63 are turned through mounting holes 62 in wall 44 of outturned flange 49 and anchored in wall 80 . wall 43 terminates in a longitudinal lip 60 , which preferably extends perpendicularly outward from the margin thereof . a flange 47 projects perpendicularly from wall 45 and terminates in a groove part 58 . walls 43 and 45 are enclosed by optional cover member 46 which is generally l - shaped . cover member 46 includes a longitudinal marginal u - shaped part 54 which fits around lip 60 and an opposite marginal hook part 56 which attaches to groove part 58 . cover member 46 is retained in place by u - shaped part 54 straddling lip 60 in the interlock of hook part 56 with groove part 58 with screws 63 being hidden from view . frame assembly 40 is easily adjusted within the opening by simple removal and replacement of screws 63 . outer frame 42 provides for a longitudinal u - shaped channel part 57 which secures window glazing panel 64 in place by use of a gasket 59 . a second window glazing panel 66 is configured to be set in preformed grooves which run horizontally along the top and bottom of frame assembly 40 . panel 66 is secured in channel part 53 within a gasket 59 &# 39 ; and may be slid horizontally , relative to panels 64 . channel part 53 is configured to receive felt weather stripping member 48 providing an insulative function when panel 66 slides relative to panel 64 . in addition , outer frame 42 is constructed to provide for a thermal barrier window 68 in periods of colder weather . window 68 is fitted into a channel part 52 which is connected to outer frame 42 . it is to be understood that the above description of the glazing panels is merely for purposes of illustration , and is not intended to limit the structure defined therein . frame assembly 40 may be adapted to accommodate other types of windows such as double hung , awning and encasement windows . it is to be understood that the scope of the invention is not to be limited to the above description , but may be modified within the scope of the appended claims .