while particular embodiments of the present invention have been illustrated and described , it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention . it is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention . in a first exemplary embodiment , a welt may be formed in a single sheet of coverstock and yield an excellent appearance . fig1 illustrates a side view of a sheet 10 of coverstock which includes a face layer 20 and a layer of foam backing 30 . the face layer may comprise a fabric layer , leather or a polymer , such as vinyl , polyurethane and polyolefin , or fiber - reinforced versions of those polymers . the foam backing layer 30 may be applied to the face layer 20 by lamination , by adhesive , by molding liquid precursors or by applying the foam layer with a doctor blade while the foam is liquid . to produce a welt in a sheet of coverstock , according to the present disclosure , the sheet 10 having ends 12 and 14 first will be folded onto itself such that the backside or foam layer 30 surfaces are in contact . this is illustrated in fig2 . this then leaves the two ends of the sheet , 12 and 14 pointing in the same direction . the sheet 10 may then be placed on a flat surface 60 and the foldline 22 of the face layer 20 placed against a vertical surface or fence 50 . in addition , a needle 40 may be placed an appropriate distance from the fence 50 such that one or more welt stitches 42 may be sewn through the ends 12 , 14 to form an extended welt head 16 . this is shown in fig3 . next , as shown in fig4 , the ends 12 , 14 of the sheet 10 are separated from one another such that the face layer 20 surfaces of the sheet are facing or overlying one another ( essentially in the shape of a “ w ”). the foldlines 32 , 34 of the foam layer 30 are then placed against the fence 50 and the needle 40 used to form one or more join stitches 44 as is shown in fig5 . in fig5 , the ends 12 , 14 of the sheet 10 have been rotated 90 ° or back into the original position as a flat sheet . an aesthetically pleasing , and in this instance a symmetrical welt 18 has now been formed which protrudes slightly from the surface of the sheet 10 . all that remains is to trim the selvage adjacent the foldlines 32 , 34 from the sheet 10 . fig6 illustrates the finished sheet 10 of coverstock including a welt 18 formed by inserting stitches 42 and 44 into the folded sheet . the excess material or selvage ( bottom portions of the “ w ”) has been trimmed off by cutting along line aa . the finished sheet of coverstock may then be used to attractively cover any number of flat or curved surfaces . accordingly , a welt has been formed in a single sheet of material . in a second exemplary embodiment , the sheet 10 ′ of coverstock may be attached to a second sheet 100 to form a welt 18 ′ adjacent a seam 80 between the two sheets . fig7 illustrates a conventional construction for a standard deck seam . to create the welt , two sheets of material 10 ′ and 100 are placed face - to - face along an edge 14 ′, 112 and one or more join stitches 46 are sewn to connect the sheets together adjacent that edge and form a seam 80 . the end 14 ′ of the first sheet 10 ′ and the matching end 112 of the second sheet 100 are then folded to one side of the seam 80 made by stitch 46 ( in the case of fig7 , to the left ) such that the first sheet 10 ′ is folded over beneath itself and the back surfaces of the foam layer 30 ′ are in contact . this results in the end 112 of a second sheet 100 lying under the fold of the first sheet 10 ′ to form three layers of material . next , one or more second stitches 48 may be sewn through all three layers which may locally compress the surface of the first sheet 10 ′ and form a welt 18 ′. one disadvantage of this construction is that when used as a coverstock for a relatively thin article or over a flat surface ( as on a door panel ), the three layers of coverstock may create an unsightly appearance ( bump ) at the seam / welt . this is particularly true for thicker more plush feeling coverstocks , where the foam layer may be in the order of 6 mm . thick . in addition , this construction provides two edges 14 ′, 112 of selvage or waste material which represent an opportunity for cost reduction of this construction . the word “ selvage ” as used herein is understood to mean an excess portion of a sheet of material which may be trimmed off , and as such may be waste or used by recycling . fig8 illustrates an improved welt construction where a more prominent welt 18 ″ may be formed by first shortening the end 14 ′ of the first sheet 10 ′ and sewing one or more stitches 46 closely adjacent the end 14 ′ of sheet 10 ′. next , as with the construction in fig7 , the extended end 112 of the second sheet 100 is then folded to one side of the seam 80 made by join stitch 46 ( in the case of fig8 to the left ) such that the second sheet 100 is beneath the first sheet 10 ′ and the back surface of the foam layer 30 ′ is in contact with the face layer 120 of the second sheet 100 . this results in the end 112 of a second sheet 100 lying under the first sheet 10 ′ to form only two layers of material . next , one or more deck stitches 48 may be sown through the two layers which may locally compress the surface of the first sheet 10 ′ and form a welt 18 ″ wherein the end 14 ′ of the first sheet 10 ′ is trapped between the sheets 10 ′, 100 and caused to form a hook configuration 140 . thus , an improved welt line is formed having a more prominent feature and a seam having a reduced thickness of about 50 %. further , a significant amount of trim waste or selvage 14 ′ is eliminated providing a savings in material usage , particularly for high volume applications of this invention , such as in the automotive industry . it is contemplated that the welts and seams as disclosed herein may be formed from a coverstock which does not include a foam backing , that is , comprising face goods only . it is further contemplated that the features of the present disclosure may find use in suitable applications in other transportation industries as well as in upholstery for the home and office . while particular embodiments of the present invention have been illustrated and described , it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention . it is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention .