AU752651B2 - Building block with planar wall surface bounded by recess - Google Patents

Description

S&F Ref: 463227D1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant Actual Inventor(s): Address for Service: Invention Title: Boral Hollostone Masonry (SA) Pty Ltd Main North Road Parooka South Australia 5095 Australia Daryl Wayne Elson r r Spruson Ferguson St Martins Tower 31 Market Street Sydney NSW 2000 Building Block with Planar Wall Surface Bounded by Recess The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845c "Building Block with Planar Wall Surface Bounded by Recess" FIELD OF THE INVENTION This invention relates to a building block.

This invention has particular but not exclusive application to a building block for construction where a wall face is to be lined; and for illustrative purposes reference will be made to such application. However, it is to be understood that this invention could be used in other applications, such as where ventilation is required in masonry constructions, for rendered walls, or in other applications where sheeting is to be applied to a block wall or a brick wall, such as for bill boards or such like.

DESCRIPTION OF THE PRIOR ART Conventional block or brick masonry may present an exposed face to the interior of the building or may be lined, rendered or otherwise finished to provide an acceptable interior appearance and/or function. Likewise the exterior may be exposed, may be rendered or otherwise clad.

Where the interior of a building is lined, this is most 20 often achieved by the provision of a load bearing timber stud wall, steel frame, or non-load-bearing battens, adapted to support a wall lining material. The cavities in the wall provided sound and thermal insulation, as well as providing a space for the passage of utilities such as water pipes and electrical wiring. However, the provision of the cavity forming structure is costly and, in the case of load bearing stud walls, structurally unnecessary in the light of modern, load-bearing, single skin block construction methods.

Where the interior or exterior wall is rendered or t0 plastered, service channels or passages are required to be chiseled or chased into the wall surface. This operation is also expensive to perform and may compromise the structural integrity of the wall. If a services conduit or such like is attached to the flat surface, it is unsightly and may expose the services to damage and may be difficult to keep clean.

Rendered or lath covered surfaces have the disadvantage of difficulty in installing services after the wall has been *o completed unless such services are attached to the surface of the wall.

BROAD DESCRIPTION OF THE INVENTION The present invention aims to alleviate one or more of the above disadvantages and to provide a building block which will be reliable and efficient in use.

In a broad form the present invention provides a building block including a block face comprising a plurality of integrally formed stand-offs and a recess portion defined between said stand-offs, said stand-offs standing out of the general plane of said recess portion, wherein at least a portion of one of said stand-offs is provided with means facilitating knocking-off of said portion at a region of its juncture with said recess portion.

t0 The block may comprise any suitable block such as a clay brick or block, or a solid or cored moulded concrete block. In general, it is anticipated that the present invention will provide broadest utility in the context of cored moulded concrete blocks of the type now useable in single skin, load bearing wall construction, made possible by the advent of grouted reinforcement methods.

The block may comprise one or more of the aforementioned block faces. For example, the block may present the block faces to one or more of the inner and outer surfaces as presented in a wall constructed with the blocks. In addition, the end faces of the block may be also provided with such block faces to expose the wall surface portions at wall ends and outside corners.

20 The end-of-block faces may be configured such that in a wall construction the stand off wall surface portion of one block is adapted to engage the recess portion of an *adjacent block. By this means the wall may be built dry between adjacent blocks, that is, oo .the joints between adjacent block ends may be mortarless. Of course, this interengagement property may be conferred by configuring the block ends by other 25 suitable means apart from provision of the aforementioned wall face portion and recess portion on the block end faces.

The stand offs may be configured such that the wall surface potion corresponds to the outer surface of a block of standard dimensions. However, the block may be of any selected dimensions if standard block size is not required.

selected dimensions if standard block size is not required.

rl.\I AV Tn\ Inr I 1 InAoQ tnc-NArT The stand-off may take any suitable form consistent with the objects of the present invention. The stand-off may extend out of the general plane of the recess portion by any amount consistent with the maintenance of the structural integrity of the block.

The wall surface portion of the stand-offs may comprise any suitable substantially planar shape including circular, rectangular or square.

The stand-off may be configured with means facilitating knocking off of the entire stand-off portion at the region of its junction with the recess. For example, there may be provided an undercut or other moulded-in groove in the region of its junction with the recess portion in order to provide for knocking off such as by bolster chisel if desired.

In a preferred form, the stand-off has a tapered form tapering toward said recess portion, said tapered form comprising said means facilitating knocking off. Each said stand-off may be provided with the means facilitating knocking off.

The stand-off portion may be configured such that the wall surface portion is of sufficient extent relative to the block face area to fulfil the required purpose. For example, to provide a datum for rendering or plastering the surface of a wall constructed of the blocks, the stand-off portion may comprise one or more narrow portions where large-area recesses are required. Larger-area stand-off portions may be used where the amount of render or plaster used is to be minimized, or where the rendering skill required is to be reduced by having the minimum recess are to be rendered.

20 In the case of walls to be lined, the stand-off portions may present an area of wall surface portion consistent with the requirements of the adhesive/wallboard system selected.

The stand-off portions may be oriented in any selected direction. For example, the stand-off portions may present a generally horizontal or vertical arrangement, and may be configured in the laid wall to line up horizontally or vertically throughout the wall as the case may be. The configuration may be selected to mimic the configuration of a s d g n o u •stud and/or noggin arrangement of a stud wall.

rI.\r A X rn\rI MT f 1nn')n0 R Alternatively, the stand-off portions may be configured such that the respective wall surface portions are staggered in the built wall by, for example, the use of an asymmetrical configuration of stand-offs which staggers the wall surface portions by the use of alternating orientation of the blocks between courses.

The stand-offs may extend by any selected degree across the block face. For example, the stand-offs may extend between opposed edges of the block face. However, it is preferred that the stand-offs are short of at least one edge of the block face to provide a continuity of the space defined substantially by the recesses in sheeted wall construction. The stand-offs may be configured to accommodate service provisions both 1o in the major direction of the recess portions as well as between recess portions by this means.

The stand-off portions may be disposed on the block face such that any moisture condensing or seeping into the recesses may be prevented from accumulating. To this end, the upper extent of the stand-offs when built into the wall may be provided with means for directing or shedding any moisture into the recess portions and preferably away from the wall lining material.

Where the blocks are to provide a smooth outer surface to the block side away from the block face bearing the stand-off portions, this smooth appearance may be compromised at corners in the wall where the recess portions extend to the end faces of o 20 the block. However, unless the recess portions extend to the end faces of the block, oOcontinuity of the recess space cannot be maintained.

Accordingly, in a preferred form, said one stand-off is provided adjoining an end face of S.said block and extends between upper and lower edges thereof, said means facilitating knocking off comprising a knock-out (or break-out) portion of said stand-off, a region of juncture between said knock-out portion and said recess portion having a reduced cross section to facilitate knocking off thereof, whereby removal of said knock-out portion °i provides a passage between said end face and said recess portion whereas retention of said knock-out portion occludes said passage to provide an unblemished said end face.

*gee• The knock-out portion may be so formed and arranged that it may be removed from the masonry block by striking the knock-out portion, or alternatively, it may be adapted to be broken from the masonry block. Additionally, the knock-out portion may be removed from an external corner or wall end to permit external access to the passage.

I\n'\AVi InI I I aOIR dnrn'MFF Construction of core filled concrete masonry requires that construction detritus be removed from the cores prior to being filled with reinforced concrete. It is customary to provide a lower course of clean out blocks which are generally E shaped or C shaped in plan view such that the building detritus may be removed from the open side of the clean out block when the wall has been completed.

Additionally, access may be necessary to tie reinforcing rods to starter bars protruding from the footing or foundation.

It has been customary for sheeting or other material suitable for temporary form work to be laid against the open Il-\nAV hI IT In Qo nI-AQO faces of the clean out blocks to seal the open sides So that the concrete may be poured in from the top to fill the required cavities in the cores of the blocks in the courses above the clean out block, as well as the cavities in the clean out blocks. Upon setting of the concrete, the temporary form work may be conveniently removed.

In many cases, it is difficult to properly apply the temporary form work with the result that an uneven surface may be produced and/or the liquid concrete may leak from the opening of the clean out block. The process of installing the temporary form work may be tedious, time consuming and irritating and may increase the cost of construction.

Accordingly, in a preferred form the building block of this invention is provided in the form of a multi function clean out block assembly including:a clean out block having integral back and end walls and a removable front wall; retaining means on the end wall for blocking passage of the front wall through the opening between the end walls when the front wall is disposed parallel to the rear wall; spacing means for maintaining an operative spacing bee. between the front and back walls, and wherein at least one beef face of the clean out block and/or one face of the removable e 0 front wall includes a substantially planar wall surface se. 25 portion bounded by a recess portion, a wall surface portion of said clean out block extending to an end face of said block, said extending wall surface portion comprising a removable closure portion occluding a passage between said S. recess and said end face, 30 whereby said passages in adjacent blocks in a wall construction provide a continuous path between respective said recesses upon removal of said closure portion.

*6 Where the building blocks are to be assembled into a wall to which linings are to be fixed, it is also preferred that at least one face of the clean out block and/or one face of the removable front wall has a projection formed integrally thereon, said projection being disposed inwardly from at least part of said face and defining a bearing surfac& for attachment of a wall lining.

The spacing means may be a fold down plate or arm which may be held raised while the front closure is inserted obliquely through the opening between the end walls and which falls down into an operative position when the front wall is moved into its operative position. Preferably, however, the spacing means is in the form of a resilient support means which may be interposed between the front and rear walls for maintaining an operative spacing between the front and rear walls.

Preferably, the resilient support means resiliently supports the front wall against the retaining means which may be constituted by a groove and/or flange extending vertically across the inwardly facing sides of each respective end wall.

Alternatively, the retaining means may be a peg, post or other protrusion so formed and arranged on the side walls and/or the front wall to prevent passage of the front wall through the opening between the end walls when the front wall is disposed parallel to the rear wall.

The front wall may include chamfered end portions adapted for engagement with the grooves or flanges, but preferably, a step or rebate is provided on each end of the front wall, the length of the front wall being such that it may be inserted into the clean out block betwixt the respective end walls at an angle skewed about a vertical axis.

The resilient support means may be of any form which will resiliently support the front wall against the retaining means, including a resilient or compressible solid such as an 0 elastomer or rubber in the form of a block, or a flexible container filled with a fluid which may also be compressible.

The support means may be attached to the internal face of S. the back wall or the front wall. Preferably however, the support means includes spring means which is separate from the clean out block and the front wall and the assembly is suitably dimensioned to provide a resilient bias of the front wall outwardly to engage the front wall against the retaining 8 means with a force sufficient to prevent the front wall being accidentally knocked out of position.

The spring means may be a leaf spring or shaped piece of spring steel or such like, but preferably, support means is in the form of a coil spring coiled in the shape of a waisted cylinder, such as a bed spring.

The section of the building blocks may be any shape which permits a wall to be constructed by abutting a plurality of building blocks in a repeated pattern. Preferably, however the blocks are in the form of rectangular prism and the plurality of projections are provided on at least one of the side faces. Suitably, the projections may be provided externally to the dimensions of a standard building block, but in an alternative form, the projections may extend from smaller than standard dimensions to the dimensions of a standard building block at their respective bearing surfaces.

The multi-function clean out block may be used in a method of preparing the cores of a hollow core wall assembly for filling with a settable material such that the wall includes grooves or channel integrally defined thereon between surface projections suitable for attachment of a wall lining. Such a method preferably includes providing a plurality of building blocks, at least some of which have a projection formed integrally thereon, the projection being 25 disposed inwardly from at least part of the face and defining a bearing surface for attachment of a wall lining, the block defining a multi-function clean out block assembly as described above. The multi-function clean out block assemblies are laid in a first course and hollow core blocks S. 30 are laid in subsequent courses with their respective cores aligned.

Debris which may have entered the hollow core above the clean out block from the cavity in the clean out block is ":.removed and the spacing means is inserted against the inner face of the back wall, and the front wall is inserted between the end walls and against the spacing means by inserting one end of the front wall into the core, displacing the spacing means by pressing the front wall against the spacing means until the other end of the closure plate is admitted between the end walls of the clean out block The front wall is operatively aligned substantially parallel to the back wall whereby the front wall is operatively retained by the retaining means and operatively spaced from the back wall by the spacing means and the bearing surfaces of the projections are aligned with a preferred alignment for attachment of a wall lining.

Subsequently, the core may be filled with concrete or some other settable material and the pressure of the settable material against the front wall is accommodated by the engagement of the front wall with the retaining means, and the lining is attached to the bearing surfaces of the wall.

Where the wall is to be lined, a lining is attached to the projections by an adhesive or such like.

Additionally, the clean out block may be used without its corresponding tile in any desired course or courses of the wall where, for example, a hollow duct is required, and services may be run from the duct into the hollow grooves or channels of a wall as required through the open face of the clean out block. If required or desired, an access panel may be formed in the lining attached to the bearing surfaces of the wall to permit access to the duct and/or the services passing therethrough.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a typical embodiment of the invention and wherein:- Figure 1 is a perspective view of one embodiment of a Sg: building block in accordance with the present invention; Figure 2 is an alternative embodiment for a narrow block but having wedge-shaped stand-offs; Figure 3 is an alternative embodiment having slots in the stand-offs; Figure 4 is a bracket suitable for insertion in the slots of Figure 3; Figure 5 is an embodiment of a half-height block; Figures 6, 7 and 8 are a normal block, a stretcher and a narrow block respectively showing how the stand-offs may be attached to different shapes of block; Figures 9 and 10 show respective alternative forms of blocks; Figure 11 shows an alternative form of block having the upper ends of the stand-offs sloping downward towards the body of the block; Figure 12 is a view of a hollow cored block; Figure 13 is a view of an alternative hollow cored block; Figure 14 is a view of a block having clean-out facility with standoffs; Figure 15 is a view of a tile with stand-offs for the block of Figure 14; Figure 16 shows a spring for the block and tile of Figures 14 and Figure 17 shows a partly assembled clean out block, tile and spring; Figure 18 shows the clean out block, tile and spring of Figure 17 with the tile and spring in position; Figures 19 to 23 show respective forms of block to be used with the clean out block of Figures 14 to 17, and 25 Figure 24 shows a block in accordance with the present invention and having an interlocking perp end configuration.

Referring to Figure i, stand-off block 10 is comprised of a hollow cored block 11 having eight stand-offs 13 formed on 30 a base surface 12 represented by one of the side faces of the hollow cored block 11.

The stand-offs 13 are arranged in pairs so that there are three wide channels 14 and four narrow channels 15 extending vertically between each stand-off 13.

Each stand-off 13 ends short of the upper surface of the hollow cored block 11 to define a horizontal channel 16 when corresponding blocks are stacked in either a half bond or 11 stacked bond pattern to form a wall. The stand-offs 13 are chamfered on their upper edges and vertically along the edges adjacent the wide channels 14.

In an alternative form, the stand-offs may be wedged to form splittable stand-offs 20 as shown in Figure 2. When a block such as that shown in Figure 1 is abutted against the side face of a block shown in Figure 2, four of the splittable stand-offs 20 may be removed by striking against the respective stand-offs with a mallet, bolster or mall or such like, and for blocks such as that shown in Figure 2, only two of the splittable stand-offs 20 need to be removed.

Referring to Figure 3, the hollow cored block 11 includes four cored stand-offs 25 having three vertical channels extending therebetween and ending short of the upper faces in a similar fashion to those shown in Figures 1 and 2. Each cored stand-off includes a vertical core 28 extending through the cored stand-off Referring to Figure 4, a stand-off bracket 26 includes a tang portion 24 and off-set portion 22 and a sheet mounting pin 27. The tang portion 24 is insertable into the vertical core 28 of the cored stand-off 25 and the off-set portion 22 is sized similar to the horizontal channel 16. The length of the tang portion 24 may be such that it extends fully through the vertical core 28. Preferably, however, the tang portion 24 is shorter than the vertical core 28 and an upper tang 29 is provided upwardly from the off-set portion 22 to extend into the lower end of a vertical core 28 of a corresponding hollow cored block 11 having the cored stand-offs 25 provided thereon.

Referring to Figure 5, a half-height block 25 includes two stand-offs 13 as shown and in Figures 6, 7 and 8, respective stand-off blocks 10 are shown in the normal, stretcher and narrow configurations.

In an alternative embodiment shown in Figure 9, two small stand-offs 34 are provided on the base surface 12 to provide wide vertical and horizontal channels between successive blocks laid to make a wall as described above.

A textured face 37 may be applied to the side face opposite that-of the base surface 12 to create a wall having a patterned face on one side.

In a further alternative embodiment shown in Figure two narrow stand-offs 44 are provided on the base surface 12 nearer the ends of the block and two wide stand-offs 45 are provided on the base surface 12 inwardly from the narrow stand-offs 44 and separated therefrom by two respective wide channels 46 and separated from each other by a narrow channel 47. The stand-offs preferably extend vertically from the bottom of the block ending short of the top face.

Referring to Figure 11, the stand-off block 10 includes four pairs of backwardly tapered stand-offs 48 having each respective upper end 49 sloping downward towards the base surface 12 upon which the backwardly tapered stand-offs 48 are formed.

Additionally, it will be appreciated that any of the features described in relation to each of the figures may be selected to form a block having such features in any combination to achieve the objects of this invention.

In use, a wall may be constructed from a plurality of stand-off blocks of this invention. Alternatively, a wall may be constructed from a combination of standard blocks and stand-off blocks of this invention. In both cases, a wall 25 with stand-off is provided and at least some of the projections may be provided with adhesive for fixing sheeting for linings, such as plasterboard, fibre reinforced cement sheeting, wooden panelling, weatherboard, or other decorative finishes or such like to the wall. It will be appreciated 30 that other forms of fastening may be used such as wall plugs, nails or such like.

Services such as water, gas, electricity or telecommunications may be added before or after the addition of the linings by placing the services between, or threading them through, the grooves or channels provided between the projections on the stand-off blocks.

Alternatively, a user may wish to lay services into the 13 channels and not attach a lining or the like to the standoffs, simply to protect those services from damage. It is believed that an unlined wall using the blocks of this invention will have improved acoustic noise damping over that of a flat surface.

Where a wall is required to be sealed, the joints between adjoining blocks may be provided with a sealant such as epoxy tar or such like. Alternatively, a sealant coating may be provided on the face of the wall having the projections and the linings added subsequent to such sealing.

In order to illustrate at least some of the applications for the block of this invention, it is suggested that the blocks of this invention may be used, for example, in standard commercial, industrial and residential construction of single leaf walls internal and external; load bearing and non-load bearing. Additionally, the blocks of this invention may be used in fire rated or sound rated construction; party walls and other partition walling and mortarless walling systems.

Referring to Figure 12, stand-off block 110 is comprised of a hollow cored block having three central stand-offs 113 formed on a base surface 112 represented by one of the side faces of the stand-off block 110. Additionally, the standoff block 111 includes two end stand-offs 115 with one edge flush with the end face of the stand-off block 111. The central stand-offs 113 and end stand-offs 115 include two vertical channels 114 between them.

Each central stand-off 113 ends short of the upper surface of the stand-off block 110 to define a horizontal channel 116 when corresponding blocks are stacked above one another to form a wall. The stand-offs 113 are chamfered on their edges and along the edges adjacent the base surface 112. The end stand-off 115 also includes a break out portion 117 near its upper end such that the horizontal channel 116 can be extended when required between adjoining stand-off blocks 110.

In an alternative form shown in Figure 13, an alternative stand-off block 120 includes two splittable stand-offs 121 and two central stand-offs 123 on a base surface 122 defining a central vertical channel 124 and two wide vertical channels 125. In a similar fashion to the central stand-offs 13 shown in Figure 12, the central stand-offs 123 in Figure 13 end short of the top face of the alternative stand-off block 120 to provide the horizontal channel 116.

Referring to Figures 14 to 18, a clean out block 130 includes two end stand-offs 131 each having a respective break out portion 137. Each clean out block 130 is associated with a clean out style 132 shown in particular in Figure 15. The clean out tile 132 includes three stand-offs 134, the end stand-offs 134 being set away from the ends of the clean out tile 132 and defining two vertical channels 133 therebetween additionally, each stand-off 134 ends short of the top face of the clean out tile 132 to provide a horizontal channel 136.

A spring 135 is provided to be inserted in the clean out block 130 such that the clean out tile 132 may be inserted into the clean out block 130 as shown in particular in Fig.

17 by skewing the clean out tile 132 as shown, and compressing the spring 135. Alignment of the clean out tile 132 parallel to the back face of the clean out block 130 as shown in Figure 18 permits the alignment of the stand-offs 25 134 with the end stand-offs 131 as shown in particular in Figure 18.

In Figures 19 to 23 are shown respectively a core filler block 138, an alternative core filler block 139, a half core filler block 140 for use with the clean out block 130 30 described in relation to Figures 14 to 18, and a left hand half block 141 and a right hand half block 142 for use with the alternative core filler block 139.

Each core filler block includes the central stand-offs 113 and end stand-offs 115 with the vertical channels .114 therebetween, supported on the base surface 112 to define also the horizontal channel 116 as described in relation to the clean out block 130, with the exception that the alternative core filler block 139 does not require the break out portion 117 as provided on the core filler block 138 and half core filler block 140, and the left and right hand half blocks 141 and 142 only require one break out portion 117 as shown.

The clean out block 130, clean out tile 132 and spring 135 once assembled have dimensions suitable for stacking with the stand-off of 110 shown in Figure 12 such that the lowest course of blocks may be provided with the clean out block 130 with its associated clean out tile 132 and spring 135 and stacked thereon (in a half bond pattern) stand-off blocks 110 corresponding to the stand-off block 110 shown in Figure 12 such that the vertical channels 114 align with the vertical channel 133 in the clean out block 130 and clean out tile 134.

Where a corner is required, the break out portion 117 of the stand-off block 110 is left intact so that the end face of the stand-off block 110 may mate with one end stand-off 115, and one and a half central stand-offs 113 and allow the provision of a normal mortar joint between the end stand-off 115 and the end face of a corresponding stand-off block 110.

Where a channel is required between adjacent stand-off blocks 110, the break out portion 117 of the adjoining standoff blocks may be knocked out to extend the horizontal channel 116 between the two adjacent blocks. Of course, this process may be repeated to extend the vertical channel 116 between any number of stand-off blocks 110.

In use, the multi-function clean out block of this invention may be used to form the bottom course of a single leaf core filled wall having the above described stand-off blocks stacked thereon. The bottom course is laid with the clean out blocks aligned with their open faces towards the side of the wall which is to have lining attached thereto.

After the successive courses of alternative core filler blocks 139 and core filler blocks 138 have been laid above the initial course of clean out blocks 130, the building detritus is removed from the cores through the opening in the clean out block, reinforcing bars inserted into the cores, and, if starter bars are provided, attached thereto.

The left and right hand half blocks 141 and 142 may be used at a wall ending so that a neat finish is obtained.

Thus, for a left hand ending of a wall (as viewed with the standoffs facing the viewer), a left hand half block 141 is placed upon a core filler block 138 and abutting an alternative core filler block 139.

The spring 135 is inserted into the open face of the clean out block and set against the back wall. The tile 132 is inserted into the open face of the clean out block 130 and manipulated into position. If desired, mortar may be added in the joints between the clean out block 130 and the tile 132. Subsequently, the cores are filled with concrete to provide a completed core filled wall. For outside corners, standard core filler blocks may be used instead of the alternative core filler blocks 139 for the corners themselves or blocks shaped as corner adapters may be provided.

Linings are then attached to the stand-offs to provide a lined wall, the linings being suitable materials such as plaster board, laminates, wooden panelling, metal siding or such like.

For internal walls, it will be appreciated that the 25.standoffs may be provided on both sides of the blocks such 25 that linings may be attached thereto. For multilevel constructions, core filled walls may thus be employed utilising the advantages of the grooves or channels for services. Moreover, where an internal core is left open for a service duct extending vertically through the wall, a clean 30 out block 130 may be utilised without its corresponding tile, and may be faced with its opening to either side, or in successive courses, both sides of the wall to permit services extending along the vertical duct to be introduced to the .grooves or channels provided between the stand offs of the wall constructed according to this invention.

In the embodiment illustrated in Figure 24, there is again provided a block 150 having cores 151 and wall surface portions 152 bounded by recesses 153. In order to prbvide interlocking between blocks in a course there are provided complementary perp ends having at one end a recess 154 bounded by flats 155, and on the other a projection 156 bounded by similar flats 157.

By this means there is provided a block which is prechased for services, permits direct attachment of wall lining and which permits wall laying without mortar for the perp ends.

It will of course be realised that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as is claimed in the following claims.

ft oooo** o*

Claims (9)

1. A building block including a block face comprising a plurality of integrally formed stand-offs and a recess portion defined between said stand-offs, said stand-offs standing out of the general plane of said recess portion, wherein at least a portion of one of said stand-offs is provided with means facilitating knocking-off of said portion at a region of its juncture with said recess portion.

2. The building block of claim 1 wherein the entire said one stand-off is provided with said means so as to facilitate knocking off of the entire said one stand-off.

3. The building block of claim 2 wherein said one stand-off has a tapered form tapering toward said recess portion, said tapered form comprising said means facilitating knocking off.

4. The building block of any one of claims 1 to 3 wherein each said stand- off is provided with said means facilitating knocking off.

The building block of any one of claims 1 to 4 wherein each said stand off is disposed vertically and configured such that respective stand-offs in a wall laid of a plurality of said blocks will be in substantial vertical alignment throughout the wall.

6. The building block of claim 5 wherein said stand-offs are short of at least one of the upper or lower edges of the block face to provide a lateral continuity of said recess portion. 20

7. The building block of claim 1 wherein said one stand-off is provided adjoining an end face of said block and extends between upper and lower edges thereof, S°said means facilitating knocking off comprising a knock-out portion of said stand-off, a region of juncture between said knock-out portion and said recess portion having a .reduced cross section to facilitate knocking off thereof, whereby removal of said knock- 25 out portion provides a passage between said end face and said recess portion whereas retention of said knock-out portion occludes said passage to provide an unblemished said end face.

The building block of any one of claims 1 to 7 wherein said building block is in the form of a clean out block including: S 30 integral back and end walls, a removable front wall, a retaining means on each said end wall for blocking passage of the front wall through the opening between the end walls when the front wall is disposed parallel to the rear wall, and HialAVT IMI TrT i 1inaoQ 19 spacing means for maintaining an operative spacing between the front and back walls, wherein said block face is defined by said front wall and a front face of each of said end walls.

9. A building block substantially as hereinbefore described with reference to any one of Figures 2, 11, 12, 13, 19, 21, 22 and 23 or Figures 14 to 18 of the accompanying drawings. Dated 3 December, 1999 Boral Hollostone Masonry (SA) Pty Ltd Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON 6o 0*00 0 eS*e •S 0 *e*e CC.. [I:\DAYLIB\LIBLL]08938.doc:MFF