the present invention is susceptible of embodiment in many different forms . while the drawings illustrate , and the specification describes , certain preferred embodiments of the invention , it is to be understood that such disclosure is by way of example only . there is no intent to limit the principles of the present invention to the particular disclosed embodiments . turning now to the drawings , and particularly fig1 - 3 , roof construction 10 is illustrated , broadly made up of a sloped , standing seam metal roof 12 , and an integrally formed , prefabricated metallic curb assembly 14 mounted on the roof 12 and in surrounding relation to a quadrate roof opening 16 . the assembly 14 is designed to support a roof fixture , such as an exhaust fan or skylight ( not shown ). although the roof is preferably formed at least substantially of metal , it is within the ambit of the present invention for the roof to be formed of other suitable materials ( such as composites , synthetic resin , etc .) the roof 12 is itself conventional , and is made up of a plurality of elongated roof panels 18 each having a central web 20 and upstanding , side marginal , seam - defining walls 22 . the panels 18 are in a sloped orientation , presenting a relatively higher upper end ( not shown ) and a relatively lower end ( also not shown ), with the panels 18 running lengthwise between the roof ends . this assures that rain water will be drained from the roof , such water traveling in the direction marked by arrow 24 ( fig1 ). during the construction of roof 12 , the panels 18 are placed in side - by - side adjacency , with the walls 22 being in close proximity . thereupon , a conventional seaming device is used to form substantially water - tight standing seams 26 along the lengths of the now - interconnected panels 18 . in the illustrated embodiment , the standing seams 26 are generally trapezoidal in cross - sectional configuration , with each wall 22 having a lower , angularly oriented segment 22 a , an upper segment 22 b extending from the segment 22 a , a flat top segment 22 c , and an uppermost , upstanding seam - defining wall 22 d . it will be appreciated that the illustrated seams 26 are intended to be generic , and thus do not illustrate any specific type of lapped configuration ; in practice , of course , the configuration of any particular seam is dependent upon the type of seaming device employed . the roof opening 16 is dimensioned to accommodate the desired roof fixture . in the illustrated embodiment , the opening 16 is generally quadrate ( e . g ., square or rectangular ), with a fore - and - aft length 28 and a lateral length 30 . those of ordinary skill in the art will appreciate , however , that any suitable opening shape and size is within the ambit of the present invention . the lateral length 30 crosses at least one of the standing seams 26 and , in the particular embodiment shown , the length 30 crosses a pair of adjacent seams 26 a , 26 b ( fig8 ). the curb assembly 14 is designed to be placed about the opening 16 and broadly includes upstanding , opposed sidewalls 32 and 34 , a higher end lateral wall 36 , and a lower end lateral wall 38 ( the designations “ higher ” and “ lower ” being relative to the slope of the roof 12 ). in the illustrated embodiment , the walls 32 - 38 are welded or otherwise interconnected to form a box - like structure . it is noted that the walls 32 - 38 are arranged into a shape and size that corresponds to that of the roof opening 16 , and this shape and size may be similarly varied without departing from the scope of the present invention . the sidewalls 32 , 34 are preferably identical , and each has upper and lower , inwardly extending , generally u - shaped flanges 40 , 42 . the higher end lateral wall 36 is preferably fabricated from two welded - together mirror - image wall segments 44 and 46 . each such segment has a vertical segment 44 a , 46 a , as well as a triangularly shaped , outwardly extending segment 44 b , 46 b defining a hollow interior space below the segments 44 a , 46 a ( not shown ). internally , the higher end lateral wall includes an upper , inwardly extending , u - shaped flange 48 and a trapezoidal gusset or liner 50 secured to the inner faces of the segments 44 and 46 , thereby closing the hollow interior space ( fig6 ). the segments 44 b , 46 b cooperatively define a diverter for rain water ( sometimes referred to in the art as a “ cricket ”). the cricket is configured to divert rain water laterally away from the curb assembly 14 . the lower end lateral wall 38 is equipped with an upper , inwardly extending , generally u - shaped flange 52 , and a lower , opposed , inwardly extending u - shaped flange 54 . however , it will be observed that the flange 54 has a pair of laterally spaced apart , upstanding , integral cap sections 56 , which are important for purposes to be described . moreover , the wall 38 has a pair of through - openings 58 which are identically configured and in registry with the respective cap sections 56 . each of the walls 32 - 38 is provided with thermal insulation 60 throughout the lengths thereof , which may be fiberglass or some other suitable insulative material . in the case of the sidewalls 32 , 34 and lower end lateral wall 38 , the insulation extends between the opposed upper and lower flanges thereof . the insulation for higher end lateral wall 36 extends from the upper flange 48 downwardly to the bottom margin of the liner 50 . in some instances , the insulation associated with the higher end lateral wall 36 is provided by the roof insulation , with such insulation being wrapped up into the curb assembly 14 against the liner 50 . the overall curb assembly 14 also includes higher end connection structure 62 secured to and extending from the lower margin of lateral wall 36 . the structure 62 includes a flat plate 64 equipped with a pair of spaced apart caps 66 , which are configured to mate with and cover the ends of the standing seams 26 crossed by the opening 16 . also , the lower edges of the segments 44 b , 46 b are welded to the plate 64 . in detail , each cap 66 has a pair of opposed , converging sidewall sections 68 and a surmounting top cover 70 secured to the sections 68 . as illustrated in fig4 , the sidewall sections 68 include a lower , inwardly extending , inclined wall 72 and an upper wall 74 . the walls 72 , 74 are designed to overlie and mate with the segments 22 a , 22 b described previously . the cover 70 has an upper section 76 configured to overlie and mate with the interconnected seam - defining walls 22 d , lateral walls 78 designed to overlie and mate with the walls 22 c , and downwardly extending walls 80 which overlie the walls 74 . in practice , the walls 80 are spot - or tack - welded to the walls 74 in order to maintain the cover 70 in place . the lower ends of the caps 66 are provided with sealing plates 81 , which are welded in place and designed to prevent passage of water into the interiors of the covered standing seams 26 ( see fig5 - 6 ). assembly 14 is also equipped with lower end connection structure in the form of the internal cap sections 56 and openings 58 . as best seen in fig7 , the cap sections 56 are welded to wall 38 and have wall sections configured to overlie and mate with the ends of the associated standing seams 26 a and 26 b . the cap sections 56 are integral and have lower wall segments 82 intermediate wall segments 84 , lateral wall segments 86 , and a top cover segment 88 . the cap sections 56 are preferably integral with and form part of the bottom flange 54 . a lower , below - roof frame assembly 90 preferably also forms a part of curb assembly 14 . as will be described , the frame assembly 90 is provided to facilitate connection of the curb assembly 14 to the roof 12 . the frame assembly 90 is preferably designed to have a complemental shape and size to the roof opening 16 . therefore , in the illustrated embodiment , the frame assembly 90 presents a generally quadrate shape that is slightly larger than the roof opening 16 . the preferred frame assembly 90 comprises four overlapped metallic channels 92 sized and oriented to lie beneath sidewalls 32 , 34 ; the side margins of plate 64 ; and the lateral width of plate 64 . the frame assembly 90 may be preassembled , or the bars 92 thereof can be individually mounted and attached , as described below . the installation of curb assembly 14 is accomplished by initially applying sealant in the form of caulking tape 94 just inside the perimeter of the assembly 14 . a relatively wide tape section 96 ( e . g ., formed by a pair of side - by - side tape strips ) is applied across the undersides of the caps 66 and the adjacent stretches of the plate 64 . side marginal tape sections 98 are applied to the undersides of the lower sidewall flanges 42 , and a tape section 100 is applied to the underside of the lower flange 54 ( including the cap sections 56 thereof ). next , the upper box - like structure of curb assembly 14 is positioned on roof 12 so that the caps 66 overlie and mate with the ends of the seams 26 a and 26 b crossed by opening 16 , and the cap sections 56 similarly overlie and mate with the opposed ends of these seams 26 a , 26 b . the frame assembly 90 is then supported beneath the roof 12 in alignment with the assembly 14 . threaded metal screws 102 are used to secure the assembly 14 in place , as illustrated in fig1 - 4 and 6 , with the screws passing through the plate 64 , lower flanges 42 and 54 , roof 12 , and the frame channels 92 . preferably , a continuous sealant bead ( not shown ), such as gun grade sealant , is applied about the entire perimeter of the curb assembly 14 between the roof 12 and the plate 64 , between the roof 12 and each of the sidewalls 32 and 34 , and between the roof 12 and the lower end lateral wall 38 . the desired roof fixture can then be installed on the curb assembly 14 in the usual manner . the curb assembly 14 is preferably metallic ( except the sealing material ), with the various components thereof preferably being welded to one another to provide a unitary , integrally formed structure . those of ordinary skill in the art will appreciate that the curb assembly may be formed of other suitable materials ( such as composites , synthetic resins , etc . ), without departing from the spirit of the present invention . the curb assembly 14 provides a number of significant advantages . first , the assembly 14 can be used with a variety of standing seam configurations . in the case of trapezoidal standing seams , it is only necessary to provide appropriately configured cap covers 70 which mate with the selected lap pattern of the seams . moreover , where other types of standing seams are employed , it is only necessary to stamp the higher and lower end connection structure to provide a mating configuration . the curb assemblies are also easy to install in the field , which reduces labor costs . provision of prefabricated components , specifically designed for a given standing seam roof , eliminates the need to field - assemble and modify the curbs . the ease of installation also helps assure that the curbs are installed in a safe , water - tight fashion . although the above description presents features of preferred embodiments of the present invention , other preferred embodiments may also be created in keeping with the principles of the invention . furthermore , these other preferred embodiments may in some instances be realized through a combination of features compatible for use together despite having been presented independently as part of separate embodiments in the above description . the preferred forms of the invention described above are to be used as illustration only and should not be utilized in a limiting sense in interpreting the scope of the present invention . obvious modifications to the exemplary embodiments , as hereinabove set forth , could be readily made by those skilled in the art without departing from the spirit of the present invention . the inventor hereby states his intent to rely on the doctrine of equivalents to determine and assess the reasonably fair scope of the present invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention set forth in the following claims .