Patent Publication Number: US-10316513-B2

Title: Construction system having corner core blocks and decorative face blocks

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional of application Ser. No. 15/597,301 filed 17 May 2018. 
    
    
     TECHNICAL FIELD 
     The invention relates to construction system having a supporting core built of corner (quoin) core blocks and optional mid-course core blocks faced with an exterior veneer of decorative face blocks mounted on the core blocks. 
     BACKGROUND OF THE ART 
     Outdoor walls and stairs are often constructed of modular blocks laid in predominantly straight lines joined at right angled corners. Corners are highly visible and modular block systems preferably provide visually appealing corner details that do not rely on the skill of the builder. 
     To construct wall and stairs to match or complement adjacent pavement blocks or pavers, the applicants have previously created a system that has supporting core blocks faced with an exterior veneer of decorative face blocks mounted on the core blocks, described in international patent application PCT/CA2016/000211 and first published as U.S. Pat. No. 9,453,341. The exposed face blocks have horizontal grooves in a rear surface that is not visible in the finished wall. The core blocks have horizontal supporting ridges on which the face blocks are hung by interlocking the grooves and ridges. 
     Use of separate face blocks mounted on core blocks has several advantages as more fully described in PCT/CA2016/000211. The use of slip molding ensures dimensional conformity and the finished wall structure assembled from the blocks complies with accurate reproducible dimensional requirements. Core blocks are not visible in the finished structures and can be mass produced from standard concrete mixes at low cost without concern for visual appeal. The unique appearance of the structure is achieved using thinner face blocks to cover the core blocks. Face blocks can be manufactured using the same materials, processes, colours, surface treatments and textures as paving blocks used in the same landscaping project. Standard core blocks can be used for the support structure of a project and manufacturing efficiencies result from high volume mass production, reduced inventory requirements and the low cost materials. A customized visual appearance of the project can be achieved by selecting visible face blocks of various colours, materials, shapes, patterns, textures and surface finishes. 
     When core blocks are stacked to form an inside corner, the ridges in each course align and provide a continuous support for the face blocks that are hung on the ridges in the inside corner. When core blocks form an outside corner, the system described in PCT/CA2016/000211, and published U.S. Pat. No. 9,453,341 Sep. 27, 2016, uses a plastic plug having an forward head shaped with a short length of supporting ridge. The rearward end of the plug is inserted into molded holes in the core blocks for support. The face blocks in an outside corner are then hung on the heads of the plastic plugs. The grooves in the rear surface of the face blocks interlock with the ridges on the heads of the plastic plugs to support the face blocks on the core blocks. 
     Forming core blocks is challenging since accurate holes are required into which the plastic plugs fit. After the concrete forms are removed, the blocks can slump slightly because the concrete has not hardened or set. Slump can tend to reduce the hole diameter or hole depth which interferes with insertion of the plug when the concrete has set. The holes also weaken the block structure and increase exposure to air which changes the curing of the concrete blocks and durability. In cold climates, the holes can fill with snow or ice or debris when stored outdoors and insertion of the plugs can be impeded. 
     There remains a demand for an economical easily constructed structural system, for walls and stairs, for example, that ensures accurate assembly of corners with a reliable and simple method of mounting the face blocks. 
     Features that distinguish the present invention from the background art will be apparent from review of the disclosure, drawings and description of the invention presented below. 
     DISCLOSURE OF THE INVENTION 
     The invention provides a construction system using core blocks having a horizontal front mounting recess in the front surface defining a core detent lip, and face blocks having a horizontal rear mounting recess defining a face detent lip, and connectors for supporting stacked courses of the face blocks suspended on the front surfaces of stacked courses of core blocks, the connectors having a rear hook and a front hook, wherein the face blocks are each supported by their rear surfaces with at least one connector, by engagement of the front hook with the face detent lip and engagement of the rear hook with the core detent lip. 
     As noted above, construction of walls from standard molded blocks involves adapting standard blocks to build wall corners, pillars, bench walls, terraces and fireplaces for example. Factors of importance include flexibility in aesthetic design to match pavement blocks, simple construction methods, low cost, minimal inventory requirements, dimensional control and standardized manufacturing processes, which can often conflict and lead to trade offs. The system described herein provides a low cost standardized core block and customized face blocks joined with low cost durable connectors which can be readily adapted for corners, stairs, walls, pillars and other structures using minimal modification. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       In order that the invention may be readily understood, an embodiment of the invention is illustrated by way of examples in the accompanying drawings. 
         FIG. 1  is a front-top isometric view of a core block with two horizontal front mounting recesses in the front surface, two slots in the rear surface, two horizontal mounting ridges in the left side surface for mounting face blocks, and matching alignment ridges and alignment grooves in the top and bottom surfaces. 
         FIG. 2  is an isometric view of a tubular connector having a rear hook engaging the rear mounting recesses of the core blocks, and having a front hook for engaging the rear mounting recesses of the exposed face blocks. 
         FIGS. 3 and 5  are front-top isometric views of a core block and four connectors showing the connectors disengaged and engaged respectively in the two horizontal front mounting recesses in the front surface of the core block. 
         FIGS. 4 and 6  are left side elevation views corresponding to  FIGS. 3 and 5  respectively. 
         FIG. 7  is an elevation view of an outside corner assembly of two core blocks showing four connectors mounted in the two horizontal front mounting recesses of the core block to the left and alignment of the slot in the rear surface of the core block arranged perpendicularly to the right to abut the left surface of the core block to the right. 
         FIG. 8  is an elevation view like  FIG. 7  with the slots and ridges engaging the core blocks together by sliding the right core block to the left. 
         FIG. 9  is a top isometric view of the two core blocks shown in  FIG. 8  to illustrate the formation of an outside corner assembly. 
         FIG. 10  is an isometric view like  FIG. 9  with a core block of a second course laid on the lower course. 
         FIG. 11  is a front surface view of the core block. 
         FIG. 12  is a front-top isometric view of the core block like  FIG. 1 . 
         FIG. 13  is a left side surface view of the core block. 
         FIG. 14  is a front-bottom isometric view of the core block. 
         FIG. 15  is an isometric view of an alternative mid-course core block suitable for laying courses between corner assemblies such as shown in  FIGS. 9-10 . 
         FIG. 16  is an exploded perspective view of an example wall assembly with a lower foundation course of slab blocks, a first course with a corner core block (as in  FIG. 4  but reversed) with the alternative mid-course core blocks of  FIG. 15  and a second course with a corner core block (as in  FIG. 4 ) with alternative mid-course core blocks in an alternating running pattern. 
         FIG. 17  is a perspective view like  FIG. 16  with the second course laid on the first course, the corner core blocks including connectors mounted in the front mounting recesses, and having horizontal mounting ridges extending along each course on the exposed outward surfaces. 
         FIG. 18  is a perspective view like  FIG. 17  with face blocks mounted on the connectors and mounting ridges. 
         FIG. 19  is a front right isometric view of a full length face block having a uniform cross-sectional profile throughout its length. 
         FIG. 20  is a right side view of the face block of  FIG. 19 . 
         FIG. 21  is a rear right isometric view of the face block of  FIG. 19 . 
         FIGS. 22, 23 and 24  show a half-length face block with views corresponding to  FIGS. 19, 20 and 21  respectively. 
         FIGS. 25 to 29  show a full length face block similar to  FIGS. 19 to 21  but having two parallel rear mounting recesses with a closed right end, for a corner assembly (see the first course of face blocks in  FIG. 18 ), where  FIGS. 25 to 29  show: a front-left isometric view; a right side view; a rear-left isometric view; a left side view; and a rear view, respectively. 
         FIGS. 30 to 34  show a full length face block similar to  FIGS. 25 to 29 , but having a closed left end for a corner assembly (see the second course of face blocks in  FIG. 18 ), where  FIGS. 30 to 34  show: a front-left isometric view; a right side view; a rear-left isometric view; a left side view; and a rear view, respectively. 
         FIGS. 35-40  show views of various examples of wall assemblies that are made from the corner core blocks, alternative mid-course core blocks and face blocks, namely: 
         FIG. 35  is an isometric view of an example wide wall assembly (not using connectors of  FIG. 2 ) with foundation slab blocks laid in a lower course and with four courses of core blocks (like  FIG. 1 ) laid with the horizontal mounting ridges on their right and left surfaces facing outward to support face blocks; 
         FIG. 36  shows an elevation view of the wall assembly of  FIG. 35  with face blocks mounted on the horizontal mounting ridges of the core blocks; 
         FIG. 37  shows an elevation view like  FIG. 37  but with alternating courses of core blocks and face blocks laid in an in/out staggered pattern; 
         FIG. 38  shows an elevation view like  FIG. 37  but with a left side having face blocks only, and the core blocks and face blocks laid in a leaning or battered pattern suitable for an earth retaining wall for example; 
         FIG. 39  is an elevation view similar to  FIG. 38  having face blocks mounted on both sides of the core blocks; and 
         FIG. 40  is an elevation view of a lower wall with face blocks on a left side of four lower courses of core blocks and an upper seat wall of the alternative mid-course core blocks (see  FIG. 15 ) with face blocks on both the left and right sides. 
         FIGS. 41-48  show views of a pillar assembly made from the corner core blocks, connectors and face blocks, namely: 
         FIG. 41  shows an isometric view of a completed pillar with six alternating courses of exposed face blocks with core blocks and connectors hidden from view and a slab cap block on top; 
         FIG. 42  shows an isometric view of a first course of corner core blocks for the pillar of  FIG. 41  with connectors and horizontal mounting ridges facing outward for mounting face blocks thereon; 
         FIG. 43  is an exploded isometric view of four alternating courses like  FIG. 42  to form a pillar; 
         FIG. 44  is a plan view of the course of  FIG. 42 , as well as the first and third course of  FIG. 43 ; 
         FIG. 45  is a plan view of the second and fourth courses of  FIG. 43 ; 
         FIG. 46  shows the first and second courses of the pillar construction with face blocks installed on the first course; 
         FIG. 47  shows the two courses like  FIG. 46  with face blocks on both the first and second courses; 
         FIG. 48  shows the view of  FIG. 47  with a third course of corner core blocks laid thereon; and 
         FIG. 49  shows the three courses of  FIG. 48  with face blocks on both the first, second and third courses. 
         FIGS. 50-51  show views of a stair assembly made from the corner core blocks, connectors and face blocks, namely: 
         FIG. 50  shows a sectional view along line  50 - 50  of  FIG. 51  with four levels of stairs constructed of core blocks with face blocks as risers and slab blocks as stair treads; and 
         FIG. 51  shows a perspective view of two steps having an exposed side wall with face blocks mounted thereon. 
         FIG. 52  shows an assembly of core blocks as molded together with the slip mold removed in the direction indicated with arrows. 
         FIG. 53  shows a single core block as slip molded. 
         FIG. 54  shows a side view of the core block as molded in  FIG. 53 . 
     
    
    
     Further details of the invention and its advantages will be apparent from the detailed description included below. 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  shows a slip molded core block  1 , or quoin block, that is especially adaptable for constructing corner assemblies due to the ability to support face blocks on at least three sides, but is also adaptable for use in other common structures. Adaptability to multiple uses and structures is a common characteristic of generally rectangular bricks and blocks. 
       FIG. 15  shows an slip molded alternative mid-course core block  2  as described in PCT/CA2016/000211. The alternative core blocks  2  do not utilize the connectors  3  for mounting face blocks and therefore can be a more simple slip molded shape with planar side surfaces without grooves or ridges. The alternative core blocks  2  are suitable for filling in the mid-course between outside and inside corner assemblies (shown in  FIGS. 16-18 ) that are constructed of the core blocks  1  ( FIG. 1 ) that are preferred for corner construction. 
       FIG. 2  shows a connector  3  for supporting various slip molded face blocks  24 ,  40 ,  44 ,  47  on the core blocks  1 ,  2 . Details of the face blocks  24 ,  40 ,  44 ,  47  are shown in  FIGS. 19-32 . 
     From these three simple components, with foundation slabs  55  and cap stones  57  as needed, the core of various structures can be easily constructed, for example, walls ( FIGS. 16-18 ), pillars ( FIGS. 41-48 ), and stairs ( FIGS. 50-51 ). On the inner core structure, various face blocks  24 ,  40 ,  44 ,  47  are hung to provide a visible decorative outer layer of face blocks  24 ,  40 ,  44 ,  47 . 
     The slip molded core block  1 , shown in  FIGS. 1, 12-14 , has: a front surface  4 ; a rear surface  5 ; a top surface  6 ; a bottom surface  7 ; a left side surface  8 ; and a right side surface  9 . The top surface  6  has two alignment protrusions  10  and the bottom surface  7  has multiple alignment grooves  11 . The core block  1  is slip molded to form the parallel surfaces  6 ,  7 ,  8 ,  9  as indicated with arrows in  FIGS. 52-54 . The use of alignment protrusions  10  and alignment grooves  11  and slip molding manufacturing procedures are considered to be well known by those in the trade, are described in international patent application PCT/CA2016/000211 and need not be discussed in detail herein. The alignment protrusions  10  and alignment grooves  11  are adapted for interlocking the core blocks  1  together and aligning core blocks  1  accurately in stacked courses with the left and/or right side surfaces  8 ,  9  adjacent to like core blocks  1 . When corners are constructed of core blocks  1 , the alignment protrusions  10  on a lower course that interfere with placement of an upper course, can be easily removed with a chisel or grinder. Adhesives applied to the top surfaces of the core blocks  1  serves to retain the core blocks  1  in place. 
     Each core block  1  as illustrated in the example shown has two horizontal front mounting recesses  12  in the front surface  4 . The rear surface  5  of the example core block  1  includes two slots  13  the function of which is best illustrated in  FIGS. 7-8  for receiving the horizontal mounting ridge  14  of an adjacent core block  1 . Further explanation of these features will follow. A single recess  12 , a single slot  13  or multiple recesses and slots  12 ,  13  can be provided if desired, for example when thinner of thicker blocks are made. 
       FIGS. 11-14  show different views of the core block  1  to clarify the arrangement of various features including: the two horizontal front mounting recesses  12 ; the two slots  13 ; mounting ridges  14  on both left and right side surfaces; alignment protrusions  10 ; and alignment grooves  11 . 
     As best seen in  FIGS. 3-4 , the horizontal front mounting recess  12  with a uniform cross-sectional profile. To receive the connectors  3 , the horizontal front mounting recess  12  has a front opening  15 . An upper core pocket  16  extends rearwardly and upwardly from a top edge  17  of the front opening  15  defining a core detent lip  18 . A core base  19  extends rearwardly from a bottom edge  60  of the front opening  15  to the upper core pocket  16   
     In  FIGS. 3-6 , four connectors  3  are shown that are mounted into the horizontal front mounting recesses  12 . Any number or length of connectors  3  can be used. Details of the connectors  3  are shown in  FIG. 2 . As described below, the connectors  3  are used for supporting stacked courses of the face blocks  24 ,  40 ,  44 ,  47  suspended on the front surfaces  4  of the stacked courses of core blocks  1 . The connectors  3  have a rear hook  20  and a front hook  21  defined on two sides of a top recess  22  in the top surface. The bottom surface  23  of the connector  3  is shaped for engaging the core base  19  of the horizontal front mounting recess  12  of the core blocks  1  as shown in  FIG. 5-6 . In the example illustrated the bottom surface  23  of the connector  3  is convex and the contour of the core base  19  is concave, the connector  3  and horizontal front mounting recess  12  each have a mating uniform cross-sectional profile since these shapes are simple to form, but other shapes that engage and support the connectors  3  and horizontal front mounting recess  12  are possible as well. The connector  3  in the example is a hollow tube that can be inexpensively extruded from plastic, rubber or aluminum and can be cut to any desired length with a saw. Solid or reinforced connectors  3  are also possible if increased strength is necessary. 
     The face blocks  24 ,  40 ,  44 ,  47  shown in  FIGS. 19 to 34  are hung on the connectors  3  that are supported within the horizontal front mounting recesses  12  of the core blocks  1 .  FIGS. 19 to 21  show a full length face block  24  having a uniform cross-sectional profile throughout its length. The full length face block  24  is slip formed in the direction indicated by an arrow in  FIG. 19  in a manner like a paving stone. The exposed front surface  25  and side surfaces  27 - 30  can be coloured, treated and processed in many ways to achieve various decorative features like paving stones to match or complement paving stones used in a construction project. 
     Referring to  FIGS. 19-21 , using the example of a full length face block  25 , each face block has: an exposed front surface  25 ; a rear surface  26 ; a top surface  27 ; a bottom surface  28 ; a left side surface  29 ; and a right side surface  30 . Spacer ridges  31  are provided on surfaces  28 - 30  to abut adjacent face blocks when installed in a wall structure for example. The rear surface  26  of each full length face block  24  in the example shown has two horizontal rear mounting recesses  33  extending the entire length of the block  24 . Similar to the horizontal front mounting recess  12  in the core blocks  1 , the horizontal rear mounting recesses  33  in the full length face blocks  24  have a uniform cross-sectional profile defined by a rear opening  34 , an upper face pocket  35  extending rearward and upward from a top edge  36  of the rear opening  34  defining a face detent lip  37 , and a face base  38  extending rearwardly from a bottom edge  39  of the rear opening  34  to the upper face pocket  35 . As indicated in  FIGS. 7-8 , the face blocks  24  are each supported by their rear surfaces  26  with at least one connector  3 , by engagement of the front hook  21  of the connector  3  with the face detent lip  37  and engagement of the rear hook  20  with the core detent lip  18 . Since each face block  24  has a center of gravity located at an eccentric distance from the rear surface  26 , gravity will rotate the rear surface  26  of each face block  24 , around the front hook  21  of the connector  3 , towards the front surface  4  of the adjacent core block  1 . 
     In the example shown in  FIG. 2 , the front hook  21  of the connector  3  has a cross-sectional profile to match the profile of the horizontal rear mounting recesses  33  and to engage the face detent lip  37  and upper face pocket  35 . The face block  24  can be simply held by gravity hanging on the front hooks  21  of the connectors  3 , and confined by adjacent face blocks  24  laterally, above and below. If desired compatible adhesives can be used to further secure the face blocks  24 , connectors  3  and core blocks  1  together. 
     Referring to  FIG. 1 , the core blocks  1  can be used to support face blocks  24 , not only on connectors  3  mounted in the horizontal front mounting recesses  12 , but also using horizontal mounting ridges  14  on the left side surface  8  and on the right side surface  9 . At least one or both of the left side surface  8  and the right side surface  9  of the core blocks  1  includes one or more horizontal mounting ridges  14  for supporting the face blocks  24  by their rear surfaces  26  by engagement of the horizontal mounting ridge  14  with the face detent lip  38  of each horizontal rear mounting recess  33 . 
     Different configurations of face blocks are shown in  FIGS. 19 to 34 . The size, shape and surface features of face blocks  24 ,  40 ,  44 ,  47  are only limited by the need to match the rear surface  26  and horizontal rear mounting recesses  33 ,  41 ,  45 ,  48  with the abutting core block surface. The front, top, bottom, left and right side surfaces of the face blocks  24 ,  40 ,  44 ,  47  may be adapted to any desired configuration including for example using natural stone slabs with horizontal rear mounting recesses  33 ,  41 ,  45 ,  48  cut in a rear mounting surface. 
     In the example of  FIGS. 19-21 , a full length face block  24  has two horizontal rear mounting recess  33  extending the complete width of the block  24  from the left side surface  29  to the right side surface  30 . In the example shown in  FIGS. 22-24 , a half length face block  40  also has horizontal rear mounting recess  41  that extends completely from the left side surface  42  to the right side surface  43 . A spacer ridge  32  is also provided on the side surfaces. 
     The full length face block  24  and half length face block  40  are suitable for installation where the left side surface  29 ,  42  and the right side surfaces  30 ,  43  are not exposed and not visible. For example mid-course between corner assemblies or where blocks  24  and  40  are otherwise abutting another block that covers the horizontal rear mounting recesses  33 ,  41 , the side surfaces  29 ,  30 ,  42  and  43  are not visible in the finished wall. 
     In the example of  FIGS. 25-29 , a closed right end face block  44  has two parallel horizontal rear mounting recesses  45  with a closed right end  46  for use where the right end  46  is visible or exposed such as in a corner assembly (see the first course of face blocks in  FIG. 18 ). In an opposite example of  FIGS. 30-34 , a closed left face block  47  has two parallel horizontal rear mounting recesses  48  with a closed left end  49  for use where the left end  46  is visible or exposed such as in a corner assembly (see the second course of face blocks in  FIG. 18 ). In either case the horizontal rear mounting recess  45 ,  48  for a corner face block  44 ,  47  has a closed right or left end  46 ,  49  adjacent to the right side surface or the left side surface, the purpose of which is to present a finished side surface used in corner assemblies, stairs, pillars or other structures where a visible open mounting recess  45 ,  48  is undesirable. 
     An alternative core block  2  is shown in  FIGS. 1 and 16-18 . The alternative core block  2  is a solid shape slip molded along the central axis  50  and having a uniform cross-section. On front and rear surfaces, two horizontal mounting ridges  51  are shown on which the horizontal rear mounting recesses  33 ,  41 ,  45 ,  48  of the face blocks  24 ,  40 ,  44 ,  47  are engaged as shown in  FIG. 18 . The alternative core block  2  also includes alignment protrusions  52  and alignment grooves  53  to align stacked courses of blocks  2  together as seen in  FIG. 16-18 . 
     The standard components described above can be assembled together in multiple ways, including corner assemblies of core blocks  1 ,  2  clad with face blocks  24 ,  40 ,  44 ,  47 . 
       FIGS. 3-4  show the core block  1  having a front surface  4  with two horizontal mounting recesses  12  and four connectors  3  (details shown in  FIG. 2 ) in exploded view spaced apart and oriented for insertion of the rear hook  20  of the connector  3  into engagement with the upper core pocket  16 .  FIGS. 5-6  show the rear hook  20  of the connector  3  rotated and inserted into the upper core pocket  16  of the two horizontal mounting recesses  12 . The convex bottom surface  23  of the connector  3  engages the matching concave surface of the core base  19  of the two horizontal mounting recesses  12 , and is supported to resist vertical loading applied by the weight of face blocks  24 ,  40 ,  44 ,  47  that are to be hung on the front hook  21 . The core detent lip  18  is engaged in the top recess  22  of the connector  3  and resists forward movement. The connectors  3  in the installed position shown in  FIGS. 5-6  can be installed and removed by rotating into the recess  12  (clockwise as drawn) but not by vertical force on the front hook  21  since the connector  3  rests on the core base  19  of the recess  12 . 
     The tubular shape of the connectors  3  may be marginally flexible so that the connectors  3  snap lock into the matching recesses  12 . Insertion of a connector into the horizontal mounting recess  12  preferably requires a slight inward compressive force applied manually. As a result the flexible connector  3  when installed into the recess  12  exerts an outward resilient force or spring back on the horizontal mounting recesses  12  thus retaining the connector  3  in position until the face blocks  24 ,  40 ,  44 ,  47  are installed on the connectors  3 . The connectors  3  could also be retained in the recesses  12  by applying adhesives to the matching surfaces. 
       FIGS. 7-10  show the stages to construct a corner assembly using two core blocks  1  per course. Alternatively  FIGS. 16-18  show the stages to construct a corner assembly using a single core block  1  per course with alternative core blocks  2  running mid-course. In both cases the use of a novel core block  1  with connectors  3  enables face blocks  24 ,  40 ,  44 ,  47  to be installed on two perpendicular side surfaces of each core block  1  of the corner assembly in a simple low cost manner. 
       FIGS. 7-9  show views of two identical core blocks  1  arranged perpendicular to each other to start a corner assembly with a first course of core blocks  1 . The progression from  FIG. 7  to  FIG. 8  shows the alignment of the bottom surfaces  7  of both core blocks on a level surface  54 . The level surface  54  may be a course of precast concrete slabs, a poured concrete pad, or a compacted layer of limestone screenings, for example.  FIG. 7  shows the horizontal alignment of the mounting ridges  14  of the core block  1  on the left and the slots  14  of the core block  1  on the right. Connectors  3  are installed in the horizontal front mounting recesses  12  of both core blocks  1  which can be seen in all views of  FIGS. 7-9 . The horizontal rear mounting recesses  33  of the face block (one or more of  24 ,  40 ,  44 ,  47 ) are later engaged on the connectors  3  as indicated in  FIG. 8 , however in general the core block  1  are assembled first and face blocks  24 ,  40 ,  44 ,  47  are mounted afterwards.  FIG. 8  shows the abutment of the left surface  8  of the core block  1  to the left with the rear surface  5  of the core block  1  to the right and the insertion of the horizontal mounting ridges  14  into the slots  13  to form a first course perpendicular corner assembly. To place the second or upper course, an alignment protrusion  10  of the core block  1  to the right is removed with a chisel or by grinding. As seen in  FIG. 10 , the second course is placed by engaging the alignment groove  11  of the upper core block  1  with the alignment protrusion  10  of the lower first course core block  1  to the left. Adhesives may be applied to the top and bottom surfaces to ensure core blocks  1  remain interconnected when an alignment protrusion  10  is removed. The two courses of core blocks  1  in  FIG. 10  form an outside corner with connectors  3  and horizontal mounting ridges  14  alternating in courses and facing outward to support face blocks  24 ,  40 ,  44 ,  47  in a subsequent step. 
     Stated in general, in the first course shown in  FIG. 9  front surface  4  of the left core block  1  and the right side surface  9  of the right core block are aligned in a vertical plane. The horizontal mounting ridges  14  of the left core block  1  are disposed within the slots  13  of the right core block  1 . In the second course, begun in  FIG. 10 , the opposite orientation is placed to overlap joints in a running bond course common in the trade. Specifically in a second course, the left side surface  8  of the corner core block  1  of the second course and the front surface  4  of a core block  1  (shown in phantom outline) to be placed to its right are aligned in another perpendicular vertical plane. The horizontal mounting ridges  14  of the right side surface  9  of the right core block  1  (in phantom outline) are disposed within the slots  13  of the left core block  1 . 
       FIGS. 16-18  shows an example of the use of a simple alternate core block  2  (see  FIG. 15 ) in a corner wall assembly. A foundation course is laid of slab blocks  55  on a compacted substrate such as gravel or limestone screening. The first course starts with a single core block  1  on the corner with a front surface  4  having connectors  3  installed and a right side  9  having two mounting ridges  14  facing outward. The remainder of the first course shown in  FIG. 16  is made up of alternate core blocks  2  (see  FIG. 15 ) laid in a running pattern with their horizontal mounting ridges  51  facing outward. 
     The second course shown in  FIG. 16  begins with a corner core block  1  oriented to be perpendicular to and on top of the core block  1  of the first course. In an alternating manner the single core block  1  on the corner has a front surface  4  having connectors  3  installed and a left side  8  having two mounting ridges  14  facing outward. The remainder of the second course is also made up of alternate core blocks  2  laid in a running pattern with their horizontal mounting ridges  51  facing outward. 
       FIG. 17  shows the foundation course of slab blocks  55 , first course with a corner core block  1  and alternative core blocks  2 , a second course with a corner core block  1  and alternative core blocks  2 , with connectors  3  and mounting ridges  14 ,  51  facing outward to receive face blocks  24 ,  40 ,  44 ,  47 . 
       FIG. 18  shows the corner assembly of  FIGS. 16-17  with face blocks  24 ,  40 ,  44 ,  47  installed. Starting from left to right, the first course corner includes: a closed left end face block  47  (see  FIGS. 30-34 ) with closed left end  49  exposed; a half length face block  40  (see  FIGS. 22-24 ) to start the alternating course pattern; and a full length face block  24  (see  FIGS. 19-21 ). Starting from left to right, the second course corner includes: a half length face block  40 ; a closed right end face block  44  (see  FIGS. 25-29 ) with closed right end  46  exposed. In the example shown, the remainder of the first and second courses will be installed with a running or alternating pattern of full length face blocks  24  mounted on the ridges  51  until another corner or other feature is required. 
       FIGS. 35-39  show constructions of walls, without corner assemblies, using the core blocks  1  and not using the connectors  3 . Face blocks  24 ,  40 ,  44 ,  47  can be mounted to the mounting ridges  14  on the left side surface  8  and/or right side surface  9  when the core blocks  1  are oriented accordingly as shown in  FIG. 35 . When a thicker and heavier wall is desired, such as a gravity earth retaining wall, the core blocks can be oriented with mounting ridges  14  and left side surface  8  and/or right side surface  9  facing outward. 
       FIG. 36  shows an elevation view of the wall assembly of  FIG. 35  with full length face blocks  24  mounted on the horizontal mounting ridges  14  of the core blocks  1 . To produce a vertical wall, the alignment protrusions  10  are shown located in the middle of three alignment grooves  11 .  FIG. 37  shows an elevation view like  FIG. 37  but with alternating courses of core blocks  1  and full length face blocks  24  laid in an in/out staggered pattern. The in/out pattern is produced by locating alignment protrusions  10  in the outermost of the three alignment grooves  11  in alternating courses. 
       FIG. 38  shows an elevation view of a battered or leaning earth retaining wall. The core blocks  1  and full length face blocks  24  are laid in a leaning or battered pattern with a left exposed side covered with face blocks  24 , for decorative effect for example.  FIG. 39  shows a similar battered wall assembly but with face blocks  24  mounted on both sides of the core blocks  1 . The face blocks  24  on the left would be exposed and decorative. The majority of face blocks  24  to the right could be low cost without particular visual appeal, used for increasing the weight of the wall, and for reinforcing the wall structure since the face blocks  24  span across joints between the core blocks  1 . The face block  24  at the top of the wall is visible and exposed since the soil or turf is below the top edge of the wall. In such situations, a decorative or visually appealing face block  24  along the top rear edge of the wall presents a finished decorative edge as shown in  FIG. 39 . 
       FIG. 40  shows an elevation view of a lower wall with face blocks  24  on a left side made of four courses of core blocks  1  and an upper seat wall made of the alternative mid-course core blocks  2  (see  FIG. 15 ) with face blocks  24  on both left and right sides. This arrangement could be used for a terraced platform with a protective edge wall for example. 
       FIGS. 41-48  show views of a pillar assembly  56  which effectively has four corners made as described above. The pillar assembly  56  illustrated is constructed with a cap slab  57 , corner core blocks  1 , connectors  3 , closed right end face blocks  44 , and closed left end face blocks  47  however any size or shape of pillar can be constructed using the standardized components described above. 
     To start the pillar assembly, a foundation slab is poured or placed from pre-cast slabs.  FIG. 42  shows an isometric view of a first course of corner core blocks  1  for the pillar assembly  56  of  FIG. 41 . Connectors  3  are mounted in the horizontal mounting recesses  12  of each core block  1 . Horizontal mounting ridges  14  also face outward for mounting face blocks  44 ,  47  thereon.  FIG. 43  shows four alternating stacked courses to form the core of the pillar assembly. For example,  FIG. 44  shows a plan view of the first course in  FIG. 42  and the third course of the core of the pillar assembly  56  in  FIG. 43 .  FIG. 45  shows a plan view of the second and fourth courses of the core of the pillar assembly  56  in  FIG. 43 . 
       FIG. 46  shows the first and second courses of the core blocks  1  of the pillar assembly with closed left end face blocks  47  installed on the first course.  FIG. 47  shows the first and second courses like  FIG. 46  with closed right end face blocks  44  on the second course.  FIG. 48  shows the third course of corner core blocks  1  laid thereon.  FIG. 49  shows three courses with alternating courses of face blocks  47 ,  44 ,  47 . 
       FIGS. 50-51  show construction of a stair assembly made from the corner core blocks  1  laid in corner arrangements as described above, with connectors  3  and mounting ridges  14  used to mount the required face blocks.  FIG. 50  shows four levels of stairs constructed of core blocks  1  laid at right angles to each other similar to  FIGS. 7-9  described above. Referring to  FIG. 51 , full length face blocks  24  and closed left end face blocks  47  are used as visible and decorative risers and to cover exposed side walls. Stair tread blocks  58  serve as horizontal stair treads. The stair assembly can be secured together with compatible adhesives if desired. 
       FIG. 52  shows the molding arrangement of multiple core blocks  1  as molded together on a flat pallet or surface with a slip mold removed in the direction indicated with arrows. To form the slots  13  in the top surface, a press plate includes molding ridges of the same shape so that when the low slump mix is poured into the mold and pressed with the press plate, the resulting core block  1  retains the shape of the molding ridges as slots  13 . The low slump concrete mix does not deform or slump significantly and the shape of the slots  13  remain. To form the undercut shape of the front mounting recesses  12 , a mold insert  59  having the same shape is placed in the bottom of the molds before the low slump concrete mix is poured into the molds. After the press plate and slip molds are removed, the inserts  59  are removed by sliding laterally out of the formed front mounting recesses  12 . 
     Although the above description relates to a specific preferred embodiment as presently contemplated by the inventors, it will be understood that the invention in its broad aspect includes mechanical and functional equivalents of the elements described herein.