reference numeral 10 in fig1 generally identifies a covered wall unit comprising an upright structure which , in this embodiment , is a solid , one - piece , rigid , generally rectangular panel 12 having opposite , generally planar , major surfaces and a plurality of outer , peripheral , generally planar edges , one of which is identified by reference numeral 14 . reference number 20 in fig4 generally identifies another covered wall unit and comprises an upright structure which , in that embodiment , is a generally rectangular , apertured frame 16 ( see fig2 and 3 ) having a plurality of frame elements 18 bounding a central opening 22 extending through the frame . frame 16 also has outer , peripheral , generally planar edges , each identified by reference numeral 24 . returning to fig1 a channel - shaped , rigid , border element 30 is mounted on , and extends along , edge 14 of the panel 12 . the element 30 has a pair of spaced - apart arms 26 in mutual parallelism and a web 28 extending between the arms . the web 28 is fastened to and along the peripheral edge 14 , preferably by threaded fasteners . the element 30 has a generally flattened u - shaped cross - section , with the arms 26 and the web 28 bounding an outer , peripheral , open channel 32 . the panel 12 and attached element 30 are inserted into an oversized , tubular - shaped cover 34 constituted of a flexible material , such as fabric or foil . the cover 34 , also known as a bag or sock , loosely surrounds the panel 12 and overlies the channel 32 . the inner diameter of the cover 34 is designed to be larger than the outer dimensions of the panel 12 in order to provide for an easy , free insertion of the panel into the cover without ripping the cover . since the fit of the cover 34 , at this stage of the manufacture , can be characterized as &# 34 ; baggy ,&# 34 ; tensioning means are provided , in accordance with this invention , for pushing the oversized , baggy cover into the channel 32 , and for tensioning the cover to lie taut against the panel . thus , tension bar 36 having a contour complementary to that of the channel 32 is moved in the direction of the arrow a into engagement with the cover 34 and , thereupon , into the channel 32 , thereby tightly drawing the slack in the cover into the channel . the bar 36 is held in place either by friction or , preferably , by additional threaded fasteners 38 which are used to attach the bar 36 to the border element 30 and the panel 12 . the bar 36 has an outer , generally planar , finish surface 40 which extends generally perpendicularly to the plane of the panel 12 for an aesthetic , custom fit . if the cover 34 has a seam , such as seam 42 , then the seam is advantageously positioned in the channel 32 and , thereupon , when the bar 36 is inserted therein , the seam 42 is concealed , again contributing to an attractive appearance for the covered wall unit . in fig4 rather than a single border element running along the entire length of an outer edge of the structure , a pair of border elements 44 could be used . in this case , the two elements 44 face each other and together bound a sideways - open channel so that the tension bar 36 is inserted from the side in the direction of the arrow b . the cover 34 is stretched taut between the frame elements 18 as described above . although this invention has been illustrated by drawing slack portions of the cover at one side of a support structure , e . g ., outer edge 14 in fig1 or at the top of the support structure , e . g ., top edge 24 in fig4 it will be understood that , in some applications , more than one outer edge and , indeed , all of the outer edges of the support structure could be provided with an open channel in which a tensioning means is inserted . it will be understood that each of the elements described above , or two or more together , also may find a useful application in other types of constructions differing from the types described above . while the invention has been illustrated and described as embodied in a covered wall unit and method of making same , it is not intended to be limited to the details shown , since various modifications and structural changes may be made without departing in any way from the spirit of the present invention . without further analysis , the foregoing will so fully reveal the gist of the present invention that others can , by applying current knowledge , readily adapt it for various applications without omitting features that , from the standpoint of prior art , fairly constitute essential characteristics of the generic or specific aspects of this invention and , therefore , such adaptations should and are intended to be comprehended within the meaning and range of equivalents of the following claims . what is claimed as new and desired to be protected by letters patent is set forth in the appended claims .