You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
RELATED APPLICATION  
       [0001]    This application is a continuation in part and claims the benefit under 35 U.S.C. §§120 and 121 of U.S. application Ser. No. 12/383,976 filed Mar. 21, 2009 for “Prefabricate Corner Post”. 
     
    
     BACKGROUND  
       [0002]    The present invention relates to building construction, and more particularly, to decorative corner posts attachable to corners formed by exterior walls, decorative column panels and trim attached to column cores, and window or door mantles. 
         [0003]    In the construction or renovation of modern buildings having a classic or colonial style, decorative corner posts attachable to the exterior walls provide a cost effective technique for simulating structural corner posts. Such decorative corner posts can be fabricated by a supplier and delivered to the building site for installation before or after the wall exterior siding, depending on the type of post and whether the siding is wood or vinyl. The corner posts can be made of wood or cellular PVC. The latter is often preferred, because raw material of the desired color can be purchased, cut, and seam welded into intricate decorative designs. In an analogous manner, decorative trim panels and molding can be applied to raw column cores on porches or the like. 
         [0004]    With conventional corner posts and columns of this kind, the installer drills pilot holes through the post or panels for screwing or nailing the post or panel against the converging walls or column core. Window and door mantles are similarly fastened to a building wall. A careful installer would try to minimize the visibility of the fastening penetrations, but especially with pre-colored posts, panels, and mantles, any touch-up required after the installation adds to the labor cost of what should be a simple and straight forward installation. 
       SUMMARY 
       [0005]    In a general aspect, the inventive concept is directed to attaching a decorative cover having a closely conforming trim piece to a building structure, by first attaching the decorative cover with a fastener through holes in the cover, and then sliding the closely conforming trim piece along the attached cover until the trim piece overlays and hides the fastener. 
         [0006]    Installation of a decorative corner post is simplified by a trim piece that is slidable between an installation position and a final position, selectively exposing and then covering holes through which the corner post is attached to the walls at the corner of the building. 
         [0007]    In one embodiment, an angled body has adjacent panels that form an inner corner having inner flat surfaces adapted to closely engage the building corner, and outer flat surface forming an outer corner. A trim piece closely conforms to and is slidable vertically along the outer surfaces between an installation position and a final position. Each panel of the body has a through hole from the outer to the inner surface at the final position of the trim piece. In the installation position of the trim piece the through holes are exposed for receiving screws to secure the body directly to the building walls, and thereafter the trim piece can be shifted to the final position to cover the holes and screws. 
         [0008]    In the preferred embodiment a nailing flange extends from the inner flat surface of each panel, beyond the side edges, so the nailing flanges are readily accessible. 
         [0009]    In the associated method, the trim piece is shifted to the installation position to expose the holes, and the internal corner of the corner post is placed against the corner of the building. The corner post is attached to the walls through the holes, and then the trim piece is shifted into the final position. 
         [0010]    A given corner post would typically have the flange extend over the full vertical height of the building corner, with the shiftable trim pieces and associated holes located at least at the top and bottom of the corner post. 
         [0011]    It can thus be appreciated that the installation of a corner post according to the invention immediately hides all nail or screw penetrations, thus avoiding unsightly blemishes or the need to fill, sand, and touch up such penetrations. 
         [0012]    The same inventive concept can be used to provide decorative trim unit for columns, such as between a porch and the underside of an overhang or roof. A multi-side (generally four-sided) core for the column extends between and is fixed to a floor and a roof or the like. The trim unit has an angled (e.g., three-sided) front body for covering some but not all sides of the core. The front body is fastened such as by nailing or screwing to the core through mounting holes and then another, (e.g., one-sided) back body is connectable to the back edges of the front body and can also be nailed or screwed to the back side of the core, thereby completing the covering of all surfaces of the core. The mounting hole and fastener for each side of the body is at location near the top and optionally bottom of the core, such that after the fasteners have been driven in, top and optionally bottom molding or similar trim pieces can be slid over to hide the fasteners, and then glued in place. 
         [0013]    When installing a mantle according to another aspect of the invention, the vertical base of the mantle is attached to the building wall through mounting holes, while a lower, slidable trim piece is at a bottom, installation position vertically spaced from an upper trim piece that is fixed to the base. The lower trim piece is then shifted upwardly and glued to the lower surface of the upper trim piece, thereby covering the mounting holes and completing the decorative portion of the mantle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0014]    A preferred embodiment will be described below with reference to the accompanying drawing, in which: 
           [0015]      FIG. 1  is schematic view of an exterior corner of a building on which a corner post according to the invention has been attached; 
           [0016]      FIG. 2  is an elevation view of the outside of the corner post as viewed from the right of  FIG. 1 , before attachment to the building; 
           [0017]      FIG. 3  is view of the top of the corner post, tilted forward, before attachment to the building; 
           [0018]      FIG. 4  is a schematic corresponding to  FIG. 2 , showing top and bottom trim pieces in the installation and final (phantom) positions; 
           [0019]      FIG. 5  is an elevation view of the corner post before attachment to the building, from the back; and 
           [0020]      FIG. 6  shows one embodiment on a column; 
           [0021]      FIGS. 7-9  show another embodiment on a column; and 
           [0022]      FIGS. 10 and 11  show an embodiment on a window mantle or the like. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]      FIG. 1  shows a decorative corner post  10  according to an embodiment of the present invention, attached to a building  100  having left  102  and right  104  exterior walls that meet at vertical corner  106  (shown where the post has been cut away). The post  10  does not provide structural support for the building  100  or walls  102 ,  104 , but is adapted to abut with or receive edges of wood or vinyl siding  108 . The present description will focus on an embodiment suitable for use with vinyl siding. 
         [0024]    As shown with further reference to  FIGS. 2-5 , the post  10  includes an angled body  12  having adjacent panels  14 ,  16  that form an elongated inside or concave vertical corner  18  having inner flat surfaces  20 ,  22  adapted to closely engage the elongated external convex building corner  106 , and an elongated convex external corner  24  forming outer flat surfaces  26  that extend to side edges  28 ,  30 . The outer surface remains visible after the corner post is attached to the building corner. Particularly for use with vinyl siding, but not required for use with wood siding, a nailing flange  32 ,  34  extends from the inner flat surface of each panel beyond a respective side edge  28 ,  30  of the outer surface. 
         [0025]    A trim piece  36  closely conforms to and is slidable vertically along the outer surface between an installation position  38  and a final position  40 . Each panel of the body has a through hole  42 , preferably counter bored, passing from the outer to the inner surface at the final position of the trim piece. In the installation position of the trim piece the through holes are exposed for receiving screws to secure the body directly to the building walls, and thereafter the trim piece can be shifted to the final position to cover the holes and screws. 
         [0026]    The post as described above is pre-fabricated and delivered to the building site, where the installer slides the trim piece to the installation position  38  to expose the holes  42 , then places the post against the building corner as shown in  FIG. 1 , whereby the internal corner  18  of the corner post is against the corner  106  of the building. The corner post is attached to the walls  102 ,  104  through the holes  42  via fasteners such as screws or nails, and then the trim piece is shifted to the final position  40 . 
         [0027]    The body  12  and trim piece  36  are preferably made of solid cellular PVC, whereas the flange is preferably made of a semi-rigid vinyl. 
         [0028]    Preferably, for use with vinyl siding, each body panel  14 ,  16  includes a thicker base portion  44 ,  46  in which the holes are located and which defines the inner surface that closely overlies the walls  102 ,  104  and a thinner rim portion  50 ,  52 . The rim portions  50 ,  52  extend from of the base portions, and define the side edges  28 ,  30  of the outer surface  26 , with a vertical channel  54 ,  56  formed between the base portion and the nailing flange. During installation, the flanges  32 ,  34  are nailed to the walls  102 ,  104  through holes  82 , either before or after the post is screwed in through holes  42 . The channels  54 ,  56  have a width similar to the overall thickness profile of vinyl siding, for receiving the edges of the vinyl siding. The depth of the channels provides sufficient tolerance for receiving edges on siding elements that may not all be exactly the same length, while presenting a uniform external interface between the siding and the side edges  28 ,  30  of the post. 
         [0029]    In a further preference, a lateral edge  66 ,  68  of each base portion forms a bottom of a respective channel  54 ,  56 , a groove  70 ,  72  extends vertically in the bottom of each channel, and the nailing flange has a fin  74 ,  76  that is secured via interference or press fit in the groove. A flat tab portion  78 ,  80  with a vertical row of nail holes  82  adjacent the outer edge is substantially coplanar with the inner surfaces  20 ,  22  of the body, whereby both the inner surfaces  20 ,  22  and the tabs  78 ,  80  of the nailing flange lie flat against the unfinished walls  102 , 104 . 
         [0030]    The trim piece preferably has sides  58 ,  60  that extend beyond the side edges  28 ,  30  of the outer surface  26  and include guide surfaces  62 ,  64  slidable along the side edges (e.g., rim portions) of the outer surface. The sides  58 ,  60  also extend toward the nailing flange  32 ,  34 , whereby the guide surfaces  62 ,  64  cooperate with the side edges  28 ,  30  to prevent the trim piece from pulling away from the outer surface of the body. To facilitate nailing of the flanges, the tabs  78  and row of holes  82  can extend laterally beyond the outer edges of the trim pieces, but this is not necessary so long as the row of holes is accessible laterally outside of the edges  28 ,  30  of surface  26 . 
         [0031]    Typically, one trim piece  36  with holes  42  is located adjacent the top  86  of the post and another trim piece  84  with holes  42 ′ is located adjacent the bottom  88  of the post. Additional trim pieces such as shown at  90  in  FIG. 2  can also be provided with similar installation functionality. 
         [0032]    The body  12  is preferably uniform at least adjacent the top  86  and bottom  88  of the post, such that during fabrication (or even on site) the top  36  and bottom  84  trim pieces can easily be fit onto the body with the sides  58 ,  60  of the trim pieces positioned in close relation with the rims  50 ,  52 . As is evident from  FIG. 3 , once this close relationship is established, the trim pieces  36 ,  84  can be shifted centrally away from the top and bottom, respectively, with the guide surfaces  62 ,  64  preventing the trim pieces from pulling away from the body. 
         [0033]      FIG. 6  shows a schematic top view of a square trim piece  92  around a square decorative column cover  94 . The structural column  96  can be solid (as shown) or boxed by the rigid connection of four elongated, flat boards. Preferably, the decorative column  94  with at least top and bottom trim pieces  92  carried thereon, are delivered as integrated units to the site, pre-cut to a standard or custom-ordered length. The holes  98  on each trim piece element  100 ,  102 ,  104 ,  106  correspond to holes  42  in the other Figures. 
         [0034]      FIGS. 7 ,  8 , and  9  show a variation that is more convenient to install than the embodiment of  FIG. 6 , on a rectangular structural column such as wood core  96 . The three cover panels  108 ,  110 , and  112  can be considered as one side, the front, and the other side, respectively of the column. Panel  114  would thus be the back panel. In the variation, these panels  108 ,  110 , and  112  are rigidly secured together (e.g., glued and lock mitered at the factory) to form a first body  116  extending from the top to the bottom of the core and defining a first inner surface  118  for conforming to a first, three-sided portion of the core and a first outer decorative surface  120  for the core. The back panel  114  can be considered a second body extending from the top to the bottom of the core and defining a second inner surface  122  for conforming to a second, back portion of the core and a second outer decorative surface  124  for the core. 
         [0035]    Through holes  126 ,  126 ′ are provided from the outer to the inner surfaces of at least the first body, whereby at least the panels of the first body can be attached with fasteners  128  to the respective portions of the core  96 . The first body has first edges  130   a, b  and the second body has second edges  132   a, b  which are joinable with each other when the first and second bodies are both conforming to the core. This joining is preferably also by glued and lock mitered edges. When the edges are so joined the first and second bodies provide a decorative external cover for the entire core. 
         [0036]    A unitary, rectilinear trim piece  134  having three sides closely conforming to and slidable over the respective outer surface of the three panels of the first body  116 , is shifted between an installation position at which the holes  126  are exposed for receiving fasteners  128  and a final position at which the holes are covered. The second body  114  can likewise carry a slidable trim piece  136  for hiding a hole  126 ′ and fastener  128 ′ into the core. Preferably, each of the bodies has a portion of a top trim piece or cornice  138 ,  140  for the column that rigidly projects transversely from the bodies, such that a complete cornice is formed when the bodies are joined and the edges  142 ,  144  of the top pieces are glued to each other. 
         [0037]    In the illustrated embodiment, preferably each panel of the first body has a vertical short groove  146  adjacent the top and preferably the bottom of the column, and the first trim piece  134  has a plug or lug projection  148  or the like which can travel in the groove. The lug and groove align and guide the trim piece  134  (and analogously  136 ) during travel. In the installation position shown in  FIGS. 8 and 9 , the holes  126  are exposed, whereas in the final position the trim piece  134  would be shifted to cover the groove  146 , hole  126  and fastener  128 . In all embodiments a transverse surface such as  134 ′ of the trim piece can be adhered without fasteners to a rigid transverse surface such as  138 ′ of the cover (e.g., of the cornice or crown or the like) as the trim piece slides to the final position overlying the fasteners. 
         [0038]    It should be appreciated that the bottom of the column can be trimmed in a corresponding manner, i.e., such as bottom trim piece  134 A shown adhered in the final position to rigid base  138 A in  FIG. 9 ). Alternatively, the techniques described with respect to  FIG. 6  can be used at the bottom of the column. As another variation, it is not absolutely necessary that the back cover panel  114  be mounted directly onto the back side of the core  96  via holes  126 ′ and fastener  128 ′. The glued joints between  130  and  132  can in some cases be sufficient to support the back panel  114 . 
         [0039]      FIGS. 10 and 11  show one half of a symmetric mantle unit  150  having a base  152 , a crown upper portion  154  and a crown lower portion  156  spaced from the upper portion in an installation position and glued to the lower surface of the upper portion in a final position, respectively. When the lower portion  156  is in the installation position, mounting holes  158  in the base are visible. A groove  160  extends vertically in the front face of the base and a mating plug or lug  162  on the back side of the crown lower portion  156  travels in the groove, whereby the lower portion is aligned and guided during sliding between the installation and final positions. The lug and groove are configured such that the mounting holes and the groove are not visible when the crown is completed by adhering the confronting transverse surfaces  154 ′ and  156 ′. 
         [0040]    The base  152  of the mantle can include laterally extending flat flanges  164  with nail holes  166 , for initial mounting of the mantle unit to the building wall  168  in a manner that permits siding strips of the like (not shown) to be slid into a channel  170  formed between the flange  164  and a frontal portion  170  of the base, as described with respect to  FIGS. 2 and 3 .

Summary:
A method and components for attaching a decorative cover having a closely conforming trim piece to a building structure, by attaching the decorative cover to the building structure with fasteners through holes in the cover and sliding the closely conforming trim piece along the attached cover until the trim piece overlays and hides the fasteners. This technique and associated components are suitable for installing a prefabricated corner post, a decorative covering and trim for a column, and a window or door mantle.