US3222436A

US3222436A - Method of casting cementitious shingles on a sloping roof

Info

Publication number: US3222436A
Application number: US276391A
Authority: US
Inventors: Carroll L Woodworth
Original assignee: ARI ZONOLITE CO
Current assignee: Arizonolite Co; ARI ZONOLITE CO
Priority date: 1961-05-22
Filing date: 1963-04-29
Publication date: 1965-12-07
Anticipated expiration: 1982-12-07

Description

DCC- 7, 1965 c. wooDwoRTH METHOD OF CASTING CEMENTITIOUS SHINGLES ON A SLOPING ROOF Original Filed May 22. 1961 IN VEN TOR. CHQ/201.4. L. waowan ng United States Patent O 3,222,436 METHOD OF CASTING CEMENTITIOUS SHINGLES ON A SLOPING ROF Carroll L. Woodworth, Glendale, Ariz., assignor to Ari- Zonolite Co., Glendale, Ariz., a corporation of Illinois Original application May 22, 1961, Ser. No. 111,548.

Divided and this application Apr. 29, 1963, Ser. No.

6 Claims. (Cl. 264-34) This application is a division of my co-pending application Serial No. 111,548, tiled May 22, 1961, now Patent No. 3,179,999, granted April 27, 1965.

My invention relates to a method of forming a roof surface on a sloping support surface by casting roof tiles of cementitious material in situ on such support surface in adjacent positions.

It is an object of the invention to cast in place a lateral series of cementitious tiles on adjoining areas of a lateral band of the support surface, starting at an upper elevation and progressing to bands at lower elevations.

Another object is to form a roof surface by casting tiles in place on an irregulator or knobby support surface so as to lock thereto and require no other attachment to the sloping support surface. In this connection it is an object to form relatively large tiles, usually rectangular, of sufficient thickness to be held in place substantially exclusively by their weight and their interlock with the knobby support surface.

A further object is to provide a roof forming method in which the tiles as cast or as subsequently scored are substantially independent of each other in the sense that each tile can expand and contract independently of adjoining tiles whereby expansion and contraction will not tear or destroy the waterproof support surface therebeneath.

Another object is to provide a pouring method that provides a spill-out space producing a spill-out portion of the cementitious material extending into the zone of a subsequently cast tile. A further object is to cast the subsequent tile over such spill-out portion.

Still another object is to provide a pouring method which scores previously-cast but yet-unset cementitious material at one or more positions adjacent the periphery of each tile, this scoring being to a depth near or to the support surface.

A further object is to provide such a pouring method that will cast Bermuda-type tiles thicker at their lower edges than at their upper edges so as to expose a portion of the former to the weather along the common boundary of two lateral courses and provide a lateral shadow line.

Another object is to cast tiles in areas of a support surface adjoining precast peripheral tiles at the ends of a lateral course. A further object is to make possible, if desired, the pouring of cementitious material in covering relationship with a precast peripheral tile.

Further objects and advantages will be apparent to those skilled in the art from the following description of exemplary embodiments of the invention.

Referring to the drawing:

FIG. 1 is a perspective View of a small roof area showing the precast peripheral tiles in position;

FIG. 2 is a perspective view of a pouring form of the invention used in casting a majority of the tiles in a course;

FIG. 3 is a sectional view of a roof showing the pouring form of FIG. 2 in use in casting the tiles of a second course below a previously-cast course, the pouring form being shown in section as taken along the lines 3 3 of FIG. 2;

FIG. 4 is a perspective view of another pouring form ice of the invention, usually employed at the end of a course; and

FIG. 5 is a view similar to FIG. 3 showing the pouring form of FIG. 4 in use in casting the end ltile of a second course, the pouring form being shown in section as taken along the lines 5-5 of FIG. 4.

The invention can be applied to produce a weatherexposed roof surface overlying any sloping support surface 1() but finds greatest applicability in forming gently sloping roofs having pitches within the general range about 6 to l2. It will be described as applied to the production of tiles forming a Bermuda-type or shingleelfect roof, usually over conventional roof sheathing 11 suggested in FIGS. 3 and 5.

The roof should be made waterproof before casting the tiles as the latter are not relied upon for water tightness. Referring particularly to FIG. 3 it is preferable to coat the roof sheathing 11 with several layers of ahphalt mopped roofing felt 22 for Waterproofness. The surface is then preferably lightly coatedwith aggregate 13 applied to an asphalt, pitchor plastic-mopped surface of the roofing felt 12 to provide a knobby support surface for the tiles. In the preferred practice somewhat at par ticles of ore or light-weight material are used, desirably particles that will not puncture the felt 12 when walked upon before the tiles are cast.. Pea-size gravel vmay be employed as the aggregate but in all instances it is desirable to employ generally round gravel particles as distinct from particles having sharp edges which might tend to cut the roong felt 12. The aggregate particles are -sprinkled on the soft asphalt so that the lower portions of the particles embed therein and the upper portions remain exposed. It should be understood however that the invention comprehends the pouring `of the tiles on any knobby surface whether made in this manner or whether containing other undulations made for example by scratching, scoring or serrating a surface. Theplatercast cementitious .material adheres to the knobby surface and the cementitious material at the bottom of the tile will have crests and valleys conforming to the valleys and crests of the knobby surface. This anchoring aids the weight of the cast tiles in maintaining same in position without other attachment.

In the preferred practice of the invention precast peripheral tiles 15 are suitably attached in slightly spaced relationship in any conventional manner to the thus-prepared support surface 10 along its sides and bottom. Some of these tiles are designated by the letters a, b, c and a', b', and c for later reference. A row of precast ridge tiles 16 can also be applied near the roof ridge between the tiles a and a or these can be cast in place by use of the pouring forms of the invention if desired. Precast tiles are usually applied at gables, eaves and valleys of a roof.

These precast tiles may be of the same cross-sectional shape as the tiles to be cast but for uniformity of texture it is preferred that the precast tiles be thinner and later covered by a layer of the cementitious material. The invention will be described with reference to the casting of tiles that are about 2" thick at the lower edge and about 1" thick at the upper edge although it should be understood that these dimensions are merely exemplary and that tiles of various uniform or tapering thicknesses can be cast by use of the invention. With tiles of such exemplified height the precast peripheral tiles `15 and 16 may be of a thickness at least 1A less, providing a rough overlay surface on which the cementitious material can be poured and adhered to build up the height of the peripheral tiles to that of the cast tiles. The peripheral tiles 15 may be of uniform length but are staggered in length in the embodiment of FIG. 1.

-The cast tiles of the invention are progressively cast in lateral courses, starting at or near the top of the roof. A straight or closed-end pouring form 18, illustrated in FIG. 2, is used to form most of the tiles in a course starting at either end, the last tile of the course being formed by a pouring form of the type suggested in FIG. 4. The invention will be described with reference to a sequence in which the pouring is started in a left-hand area 19 of a lateral band 20 just below the peripheral tiles 16 and progressing through areas 21, 22, etc. To a right-hand area 23 of the band 20. Lower courses are cast in the same direction as the rst or upper course.

Various cementitious materials can be employed in casting the tiles depending upon the desired weight, texture, porosity, etc. of the ultimate tile. It is preferred that the cementitious material should assume an initial set or become form-retaining in a relatively short period of time so that the pouring form can be lifted rather promptly and moved to an adjoining area of the band being covered. A cementitious material that has been found very satisfactory is made by mixing one bag of Portland cement, four pounds of asbestos floats, and about two bags of aggregate. The latter may be a conventional sand-rock aggregate if heavy tiles are desired or may be a lightweight aggregate such as perlite, shale, vermiculite, etc. for tiles of lesser weight. 'Ihe asbestos floats (nely subdivided asbestos) serve to give the mixture more body and ability to maintain its shape when the pouring form is removed. They also permit pumping of the cementitious material at stilfer consistency if this type of placement is desired. It should be understood however that binders other than Portland cement can be used, e.g., foam concretes alone r with other aggregates, plastics alone or with other aggregates, etc.

Referring particularly to FIGS. 2 and 3, the pouring form 18 includes an upper upright form member 24 and a lower upright form member 25 held in parallel spaced relation by means to be described and providing casting spaces 26 therebetween. The form 18 is somewhat foreshortened in FIG. 2 for purpose of illustration. Commonly each casting space 26 will be of a length substantially greater than its width, eg., a form 18 may be of a length of 48-72 or more with a width of about 10-14.

The upper form member 24 is shown as formed of heavy sheet metal bent to form an upright portion 24a and a flange portion 24b. This upper form member provides a downwardly facing scoring edge 27 which may be straight or serrated to contact the knobby surface of the sloping support surface but which is preferably spaced a slight distance thereabove by suitable support means spaced from each other along. the length of the upper form member 24 as suggested in FIGS. l and 2.

Functioning for this purpose and to space the members 24 and 25 and outline the casting spaces 26 are two transverse end form members 28 and 29 and one or more intermediate form members 30 welded to or otherwise joining and spacing the form members 24 and 25. At least the upper and lower ends of the lower edge of each of the

form members

28, 29 and 30 engage the knobby surface to support the form 18 with the scoring edge 27 slightly above the knobby surface for a purpose to be described. In the illustrated embodiment the lower edge of each of the

form members

28, 29 and 30 is in a straight line to engage the knobby surface throughout the length of such form member. The

form members

28, 29 and 30 bound the lateral sides of the casting spaces 26 and are of a shape substantially corresponding to the cross-sectional shape of the desired tile. The top of each

such form member

28, 29 and 30 provides a screed surface 33.

The lower form member 25 is shown as a length of angle iron welded or otherwise secured to the end form members 28 and 29 so that its lower flange is angled slightly with respect to the screed surfaces 33 and support surface 10, see FIG. 3, Support means are provided spaced from each other along this ange to hold it above the surface 10 to provide a spill-out space 36 between a spill-out edge 37 of the flange and the support surface 10 for a purpose to be described. The end and

intermediate form members

28, 29 and 30 function as such a support means. The spill-out space 36 is of uniform height throughout its length, preferably about half or somewhat less than half the thickness of the desired tile at its lower or thicker end.

Handles

38 and 39 may be respectively welded to the upper and lower form members 24 and 25 the handle 39 preferably angling forwardly of the lower form member for better operation of a screed utilized in a manner to be later described.

In addition to the straight or closed-end pouring form described above the invention preferably includes a terminal pouring form 40, shown in FIG. 4, used to pour the terminal tile of a course adjoining one of the perimeter or peripheral tiles such as b. This terminal pouring form includes upper and lower form members 44 and 45 spaced to dene a casting space 46 therebetween which is here not divided.

The upper form member provides an upright portion 44a and a flange portion 44b the former terminating in a downwardly facing scoring edge 47. Like the scoring edge 27, the edge 47 may contact the knobby surface of the sloping support surface 10 but is preferably spaced a slight distance thereabove by suitable support means spaced from each other along the length of the pouring form 40 as suggested in FIGS. 4 and 5. Functioning for this purpose at one end of the pouring form is a transverse end form member 49 welded to or otherwise joining and spacing the form members 44 and 45. At least the upper and lower ends of the lower edge of the end form member 49 engage the knobby surface to support the scoring edge 47 a small distance thereabove. In the illustrated embodiment the lower edge of the member 49 lies in a straight line to engage the knobby surface throughout its length. Functioning to support the other end of the scoring edge is a leg 51.

The end form member 49 closes one end of the casting space 46 and is of a shape substantially corresponding to the cross sectional shape of the desired tile. The top of this member 49 provides a screed surface 53.

As before, the lower form member 45 is shown as a length of angle iron with its lower flange angled with respect to the screed surface 53. Suitable support means provide a spill-out space 56 between a spill-out edge 57 of the flange. The form member 49 functions as such a support means at one end of the pouring form 40. At the other or open end of this form a leg 58 serves as a support and is of such height as to make the spillout space 56 of uniform height throughout its length.

Toward the open end of the pouring form 40 the upper and lower form members 44 and 45 are secured to and spaced by a transverse spacing structure 60 comprising uprights 61 joined by an angle iron member 62 and a member 63. The spacing structure 60 is preferably disposed completely above the casting space 46 so as not to obstruct the open end thereof. It preferably angles away from the end form member 49, e.g., leftward from the left end of the form members 44 and 45, although this is not absolutely essential. The angle iron member 62 may serve as a handle to aid in the lifting and moving of the pouring form 20 as may also handles 64 and 65 respectively welded to the upper and lower form members 44 and 45.

Between the end form member 49 and the spacing structure 60 is a screed member having an upper screed surface 67 parallel to and of the same height above said support surface as the screed surface 53 of the end form member 49. This screed member is preferably in the form of a taut wire 69 having one end anchored to the lower form member 45 by a screw 70. The other end extends through an opening of the upper form member 44 drilled at the appropriate height and is maintained taut by being threaded through an opening of the flange por- .5 tion 44h around which it is looped to be secured by a screw 71. The wire 69 is strongly tensioned in its section traversing the casting space 46 and is easily replaced if broken.

In operation the straight or closedend pouring form 18 of FIG. 2 is first positioned over the left-hand areas 19, 21 and 22 of the lateral band 20. If desired it can straddle the perimeter tile b to cast a cap or surface layer thereon. The upright portion 24a of the upper form member abuts against and is aligned by the lower edges of the previously laid upper course of tiles, here the peripheral tiles indicated at a and by the numeral 16.

In this position an amount of cementitious material is poured, pumped or otherwise placed in the casting spaces 26, preferably to a localized level above the screed surfaces 33. A fiat screed, indicated by the dotted lines 75 of FIG. 3, is then drawn downward along the screed surfaces 33. This determines the top surface of the three tiles and applies pressure to the cementitious material forcing the excess through the spill-out space 36 to form a spill-out portion 77 extending downwardly into the next lower laterial band with irregular but progressively decreasing thickness. This spill-out portion 77 aids in supporting the thick ends of the tiles when the form is later lifted and serves other desirable functions. The tiles in the lower or second band are subsequently cast over the spill-out portion 77. The tiles will be divided by the members 30 and the right-hand end of the last tile will be shaped by the end form member 29. lf some of the cementitious material exudes between the lower edge of the end form member 29 and the support surface 10 or if this member provides a spill-out space similar to the space 36, the next cast tile will overlay the spill-out portion.

Several of the pouring forms 18 can be positioned endto-end along the course and can be filled in sequence, the first-filled form being lifted first and placed in a succeeding position. In this way the entire course can be progressively cast up to the last or right-hand area 23, which is cast by use of the pouring form 40 of FIG. 4. This pouring form permits casting of the last tile to fill the area 23 which is usually of a length greater or less than the previously cast tiles. It can be positioned with its end form member 49 abutting the perimeter tile b and with its legs 51 and 58 straddling a previously cast tile. The casting space 46 is then filled, the left-hand end of the resulting tile being formed against the end of the last cast tile produced by the pouring form 18 of FIG. 2. In casting the last tile of the course the end form member 29 may abut the precast peripheral tile b' either at its inner edge (if no cap is to be poured thereon) or its outer edge (if such cap is to be poured simultaneously with the last cast tile ofthe course). Irrespective ofthe space between the previously cast title and the peripheral tile b the intervening space will be spanned by the form members 44 and 45 which can straddle any portion of such previously cast tile. The last cast tile of any course may thus be of any length and will lill the remaining space up to the peripheral tile b.

When the pouring form 40 is lifted after casting of the last tile of a course the end form member 49, if adjacent the inner edge of the precast tile b', will leave a narrow space or score line separating the cast material and the precast tile. It is desirable to form similar narrow spaces or score lines at the junction of such last cast tile and its predecessor. In this connection at a suitable time after pouring a suitable scoring tool may be pressed into the cast material to the depth of the support surface or slighly thereabove. This may also be done at the junctions of earlier-poured tiles of the course. If desired each unitarily cast tile may be similarly scored at intermediate positions along its length to provide a desired pattern.

In forming the next lower course of tiles the pouring form 18 abuts or straddles the precast tile c, the tiles being cast in sequence as before. The upper form member 24 abuts, against the lower edge or edges of the tile or tiles of the previously-cast course. The scoring edge 27 of this upper form member automatically penetrates the spill-out portion 77 of the previously-cast tiles of the adjacent upper course, thus automatically scoring this junction to a position slightly above the supporting surface 10. If scoring is not completely to the support surface the shrinkage of the cementitious material when hardened will crack any joining portion of the tiles of the ltwo courses so that they remain independent olf each other 1n use.

The tiles of a previously cast course thus align the form of the next course so that when the lowest course of the roof is poured adjacent the peripheral tiles 15 at the eave line all courses will have parallel and straight shadow lines. If the height of the spill-out

spaces

36 and 56 is made equal to or less than the height of the precast eave tiles 15 at their narrow sides there will be no spill-out portion 77 on such peripheral eave tiles 15. However the pouring form 18 can be used to pour a cap of the cementitious material on these precast eave tiles if they are of substandard height.

The roof may be capped by a ridge cap 8 shown in FIG. l. This may be cast in sections by conventional forms.

The resulting roof is in effect composed of a plurality of independent tiles having lower surfaces corresponding to the undulations of the knobby surface on which they are poured. They need not be otherwise secured to the support structure of the roof as their weight and their adhesion to the knobby surface suices to maintain them in position. These tiles can independently expand and contract without danger of tearing the waterproof layer formed by the felt 12. They can be left in their natural state or they can be painted. The finished roof will have distinct shadow lines in view of the fact that the thinner upper edge of each tile is adjacent the thicker lower edge of the tiles of an adjacent upper course. The resulting roof has excellent insulation properties because of the thickness of the cementitious material. It is as permanent as the waterproof -felting 12 and greatly increases the life of the latter in protecting it from the sun.

Various changes and modifications will be apparent to those skilled in the art from the foregoing description and are within the scope of the appended claims.

I claim:

1. A method of forming a tiled roof surface of cementitious material on a sloping support surface, including the steps of:

(a) casting on an upper portion of said sloping support surface an upper tile of cementitious material having an upper edge and having a lower edge spaced downwardly along said sloping support surface from said upper edge of said upper tile;

(b) restraining the upper portion of the cementitious material of said lower edge of said upper tile against movement downwardly along said sloping support surface while simultaneously permitting cementitious material below said upper portion of said lower edge of said upper tile to ow downwardly along said sloping support surface to form a lower, spillout portion;

(c) removing the restraint against movement of said upper portion of said lower edge of said upper tile downwardly along said sloping support surface after said lower edge of said upper tile has set suiciently to substantially retain its cast shape; and

(d) casting on a lower portion of said sloping support surface, spaced downwardly along said sloping support surface from said upper portion thereof, a lower tile of cementitious material having an upper edge overlying said lower, spill-out portion of said upper tile and having a lower edge spaced downwardly along said sloping support surface lfrom said upper edge of said lower tile. 2. A method of forming a tiled roof sur-face of cementitious material on a sloping support surface, including the steps of:

(a) casting on an upper portion of said sloping support surface an upper tile of cementitious material having a thin upper edge and having a thick lower edge spaced downwardly along said sloping support surface from said upper edge of said upper tile;

(b) restraining the upper portion of the cementitious material of said lower edge of said upper tile against movement downwardly along said sloping support surface while simultaneously permitting cementitious material below said upper portion of said lower edge of said upper tile to flow downwardly along said sloping support surface to form a lower, spill-out portion;

(c) removing the restraint against movement of said upper portion of said lower edge of said upper tile downwardly along said sloping support surface after said lower edge of said upper tile has set su'iciently to substantially retain its cast shape;

(d) casting on a lower portion of said sloping support surface, spaced downwardly along said sloping support surface from said upper portion thereof, a lower tile of cementitious material having a thin upper edge overlying said lower, spill-out portion of said upper tile and having a thick lower edge spaced edge of said upper tile and said upper edge of said lower tile; and

(f) scoring said lower tile, and at least part of the underlying lower, spill-out portion of said upper tile along a horizontal line at the junction of said lower edge of said upper tile and said upper edge of said lower tile, and to a depth close to said sloping support surface.

4. A method of forming a tiled roof surface of cemen- 10 titious material on a sloping support surface, including the steps of:

(a) securing precast peripheral tiles in abutting relationship along the sides and bottom of said support surface thereby leaving a central portion of said support surface bounded by such peripheral tiles said central portion including a substantial area of said support surface;

(b) subsequently sequentially casting tiles of cementitious material in lateral courses with some of the cast tiles being immediately adjacent said precast peripheral tiles to substantially lill said central portion with said sequentially cast tiles; and

(c) utilizing such precast tiles to align at least some of the sequentially cast tiles therewith.

5. A method of forming a tiled roof surface of cementitious material on a sloping support surface, including the steps of:

(a) securing precast peripheral tiles along the sides and bottom of said support surface thereby leaving downwardly along said sloping support surface from a central portion of said support surface bounded said upper edge of said lower tile; and by such peripheral tiles;

(e) said upper edge of said lower tile, including the (b) subsequently casting tiles and spill-out portions of underlying lower, spill-out portion of said upper tile, cementitious material in lateral courses to substanbeing cast with a thickness less than the thickness tially ll said central portion, said spill-out portions of said lower edge of said upper tile to provide a extending downwardly from the lower edges of the horizontal shadow line at the junction of said lower tiles in each of said lateral courses and supporting edge of said upper tile and said upper edge of said said lower edges of said tiles against movement lower tile. downwardly along said sloping support surface; and

3. A method of forming a tiled roofl surface of cemen- (c) using such precast tiles to align at least some of titious material on a sloping support sur-face, including the steps of (a) casting on an upper portion of said sloping support surface an upper tile of cementitious material having the subsequently cast tiles therewith. 6. A method of forming a tiled roof surface of cementitious material on a sloping support surface, including the steps of:

a thin upper edge and having a thick lower edge spaced downwardly along said sloping support surface from said upper edge of said upper tile;

(c) removing the restraint against movement of said upper portion of said lower edge of said upper tile downwardly along said sloping support surface after said lower edge of said upper tile has set sufficiently to substantially retain its cast shape;

(d) casting on a lower portion of said sloping support surface, spaced downwardly along said sloping support surface from said upper portion thereof, a lower (a) securing precast peripheral tiles along the sides and bottom of said support surface thereby leaving a central portion of said support surface bounded by such peripheral tiles;

(b) casting a top row of tiles and spill-out portions on said central portion to form a top lateral course, said spill-out portions being at the lower edges of such cast tiles and of lesser height than such lower edges;

(c) casting a next-lower row of tiles and spill-out portions on said central portion with the tops of such tiles overlying the spill-out portions of the tiles of said top row, to form a next-lower lateral course; and

(d) casting additional next-lower rows of tiles on the remaining area of said central portion to form additional lateral courses substantially filling such remaimng area.

References Cited by the Examiner tile of cementitious material having a thin upper UNITED STATES PATENTS edge overlying said lower, spill-out portion of said (e) said upper edge of said lower tile, including the underlying lower, spill-out portion of said upper tile, being cast with a thickness less than the thickness of said lower edge of said upper tile to provide a horizontal shadow line at the junction of said lower ROBERT F. WHITE, Primary Examiner.

ALEXANDER H. BRODMERKEL, Examiner,

Claims

1. A METHOD OF FORMING A TILED ROOF SURFACE OF CEMENTITIOUS MATERIAL ONA SLOPING SUPPORT SURFACE, INCLUDING THE STEPS OF: (A) CASTING ON AN UPPER PORTION OF SAID SLOPING SUPPORT SURFACE AN UPPER TILE OF CEMENTITIOUS MATERIAL HAVING AN UPPER EDGE AND HAVING A LOWER EDGE SPACED DOWNWARDLY ALONG SAID SLOPING SUPPORT SURFACE FROM SAID UPPER EDGE OF SAID UPPER TILE; (B) RESTRAINING THE UPER PORTION OF THE CEMENTITIOUS MATERIAL OF SAID LOWER EDGE OF SAID UPPER TILE AGAINST MOVEMENT DOWNWARDLY ALONG SAID SLOPING SUPPORT SURFACE WHILE SIMULTANEOUSLY PERMITTING CEMENTITIOUS MATERIAL BELOW SAID UPER PORTION OF SAID LOWER EDGE OF SAID UPPER TILE TO FLOW DOWNWARDLY ALONG SAID SLOPING SUPPORT SURFACE TO FORM A LOWER, SPILLOUT PORTION; (C) REMOVING THE RESTRAINT AGAINST MOVEMENT OF SAID UPPER PORTION OF SAID LOWER EDGE OF SAID UPPER TILE DOWNWARDLY ALONG SAID SLOPING SUPPORT SURFACE AFTER SAID LOWER EDGE OF SAID UPPER TILE HAS SET SUFFICIENTLY TO SUBSTANTIALLY RETAIN ITS CAST SHAPE; AND (D) CASTING ON A LOWER PORTIN OF SAID SLOPING SUPPORT SURFACE, SPACED DOWNWARDLY ALONG SAID SLOPING SUPPORT SURFACE FROM SAID UPPER PORTION THEREOF, A LOWER TILE OF CEMENTITIOUS MATERIAL HAVING AN UPPER EDGE OVERLYING SAID LOWER, SPILL-OUT PORTION OF SAID UPPER TILE AND HAVING A LOWER EDGE SPACED DOWNWARDLY ALONG SAID SLOPING SUPPORT SURFACE FROM SAID UPPER EDGE OF SAID LOWER TILE.