MANUFACTURING AND USING THE SAME
Year: 1884

page_text: MANUFACTURING AND USING THE SAME, to be as described under; the
six following headings:
I. A description of the Slab.
II. The process of manufacturing the Slab including a description of the
Mould.
III: The method of using the Slab and the special constructions consequent
thereon.
IV. A description of the application of the Slab to other than ordinary work
(such as Chimney Shafts et cetera).
V. The advantages of this method of construction.
VI. The invention claimed.
I. Our invention consists of a Slab of concrete or any other suitable material
having a finely finished (plain or ornamental) face and a sunk, panelled, or recessed
back. The sunk recess is equal in depth to about half the thickness of the Slab
and is so sunk as to leave a narrow parallel margin all round the Slab whilst the
inner edges are undercut in order that the Slabs when in position may be thereby
securely keyed to the mass of concrete behind them. In the top and bottom edges
of the Slab are vertical dovetailed inortices, those in the bottom extending right
through to the panel which is here dished out to facilitate the operation of pouring
in the cementing material to bind the Slabs together; while those in the top edge,
in order to retain the cementing material, only extend through to within about half
an inch of the panel. A narrow groove is formed all round the. edge of the Slab
with the object of joggling the Slabs together and also preventing the concrete
filling-in from oozing through and running down the face of the work. This groove
may be partially or wholly omitted and is in certain cases formed on the face or
back of the Slab, this being effected by a simple alteration in the mould.
set with breaking-joints (which is done by the use of half Slabs) the mortices of
the Slubs in the course below correspond with the mortices of those in the course
When

page_text: above and are filled-in with a plastic material which hardens and keys the several
Slabs together. The Slab may be made to any size and proportion but it is better
to maintain a fixed height and to alter the length to suit the various kinds of work.
We find 12" by 18" by 1" a very convenient size and if this be adhered to we
make, for work which is confined solely to the use of these Slabs, short Slabs
(12" x 16" x 1"), half-Slabs (12" x 9" x 1") short-half-Slabs (12″ × 7"x1"),
and closures (12" x any length x 11"). With Slabs of these dimensions any specific
measurements may be worked to and proper bond ensured. Figures IX and XI in
the drawings appended, represent the back and face views of the Slab and Fig: X
shews the Slab exposed in section. Figures I and II shew Slabs used for angles
both internal and external. In figure XVI is shewn a half Slab for an internal
angle, and in figure XVII is shewn a half-Slab to be used in all other positions,
except at the angles, to cause proper bonding of the Slabs.
II. Wo cast the Slabs in moulds made of a solid wood or metal frame having four
immoveable sides (Fig: XII). Disorders resulting from wear and the consequent
imperfections in the manufacturo of Slabs made in alterable moulds are thus
avoided and the production of clean and accurate Slabs is thereby ensured. In each
of the two longer sides of the mould are two perforations into which are placed
metal keys to form the dovetailed-mortices in the top and botton edges of the Slab.
Other perforations are made in the sides of the mould for the purpose of fixing the
square metal tongues to form the groove round the edge of the Slab. The dove-
tailed-keys are put into their respective mortices and the tongues are also put into
their respective places, those on the top and bottom edge of the mould passing
through the dovetailed-keys. The frame is now placed on a bench having a wood,
metal, glass, or other suitable top and inside it is put an indiarubber core (or cores)
which forms the panel (or panels) at the back of the Slab. The core is made in the
shape of the lower portion of a pyramid cut by a horizontal plane parallel to its
base and is inverted and kept (by means of dowels at its back) in a position
parallel with the sides of the mould and so as to form an equal margin round the
Slab. It is shewn in the drawing numbered XII at X and Y.: In order to use
less indiarubber we make only the edges of this core of that material and fill-in the
centre with wood or metal. The core being constructed of indiarubbor enables us
to withdraw it easily when the plastic material of which the Slab is composed, has
set. The mould is now ready for the purpose of casting a plain Slab and has only
to be filled-in with the material and trowelled-off. When sufficiently hard the
tongues and keys are removed and the Slab is easily taken out. For a Slab to
which mouldings, sets-off, or any ornaments are to be applied, the ornaments are
first cast in suitable moulds, or if made of solid material is worked, to the
dimensions (length or breadth) of the Slab,-allowing, besides their proper projection
.beyond the face of the work, an extra width for tailing into the Slab. They are
then placed in the mould and the plastic material is made-good up to them and
then trowelled-off. Figures III and IV shew Slabs with vertical or horizontal
mouldings applied to them. Besides making rectilineal Slabs we make them
convex or concave and to any curve either on plan or elevation. (Figs: VII
and VI). To do this the sides of the mould are bent to the required curve, or
a white-metal pattern is made and bent, and castings are taken from it. For
domicular and pyramidal and conical construction special moulds are made for each
course. The inner shell of these constructions is first built up to the apex and the
filling-in is carried on with the rise of the outer shell. No centering is required
for this construction. We also apply thin slabs, as well as mouldings, of marble or
other ornamental materials to the face of the concrete slab whilst it is in a plastic
state and so arranged as to be securely keyed to the concrete when it has set.
III. To build a structure and to use these Slabs to the greatest advantage we
adopt the following method :-
The trenches are excavated to the required depth and to an uniform level
Boards are then fixed to the necessary batter by means of the irons and in the way

page_text: shown in figures XIX and XX, and concrete is placed between them and allowed to
set. The boards are then removed. This operation is continued in sections until
the whole of the footings of the building have been brought up to the ground-level.
An asphaltic or other damp-course is next laid upon the footings and upon this is
set the horizontal Sole Slabs (shewn at XVIII) which are accurately levelled and
form the wall-base. As soon as the wall-base has been fixed round the building
the quoin-slabs are next put in position and may consist of special quoin-slabs
having a groove on one face instead of on the end (shewn at I. II. XIV and 30).
The key-mortices in the lower edge of the Slabs in the first course coincide with
the key-mortices of the wall-base whilst those in the upper edge of the Slabs
coincide with those in the lower edge of the second course (see figs: XXI and XXII)
and the Slabs are fixed by pouring a quick-setting liquid cement into the key-
mortices which holds the two firmly together. We use for keying the Slabs
together such cements as compounds of bitumen and those substances which liquify
on being heated and harden on cooling besides ordinary cements. The liquid
cement is also poured into the groove extending round the edge of the Slab.
Thus the courses are built up. Where openings occur the jambs and lintel (and in
window openings the sill) are cast in solid concrete or worked in stone or any
building material and the Slabs are made to butt against them (Fig: 23); tho
groove in the Slab corresponding to a similar one in the solid block. When
necessary, for the sake of good bond these blocks are made with recesses similar to
those formed in the back of the Slab (as shewn at À lig: 23) or they may be the
counterpart of them (as shown at B. 23), thus securely binding the whole mass
together when the space behind has been filled-in. Lintels over window or door
openings may also be made in the same way as described for chimney breasts
(shewn in fig: 28), the formation of passages and air spaces for purposes of venti-
lation being thereby facilitated. It is preferable to make the solid blocks of the same
height as the Slabs, or vice versa. For carrying floors at different heights of the.
wall, sets-off are made (figs V and 24), openings are formed, or corbels (fig XV) are
moulded on the Slabs (in the same way as described for mouldings) and upon these
the floors are constructed in the usual manner. Besides the ordinary methods of
constructing floors and ceilings we employ T or I iron joists with a modification
of our Slab keyed on to the undersides of them by means of bituminous cement
poured, at intervals, round the lower flange of the iron joist which is placed in a
dovetailed cavity formed in the Slab as shewn in Fig: 31. The iron joists with
the slabs keyed to them are then placed in position and levelled at the proper
distances apart, and other Slabs rebated so that their face shall appear flush with
the faces of the Slabs beneath the joists, are filled in between then with breaking
joints: thus forming the ceiling beneath the floor. The upper sides of these Slabs
have recesses formed in them in the same manner as described for walling and when
the plastic concrete is shot between the iron joists and, supported by the Slabs
beneath, has set a solid concrete floor is forined the top of which may be finished-off
in the usual manner. Chimney breasts externally are constructed in the same way.
as other portions of the wall (Figs: 24 and 28) except over the opening for the fire
place where Slabs having dovetailed mortices in the sides (as well as the top) are
used and these are keyed together by means of a cement before they are put in
position and are then put across the opening thus forming the skeleton front of a
lintel. A kind of center made of wood or other suitable matorial with the lower
edge projecting beneath the skeleton lintel and so arranged that it may be with-
drawn (as shewn in Fig: 28) is used for tho gather of the flues, and flue pipes or
a core is used to form the flue. Plinths and heavy cornices which do not come
under the description of sets-off and mouldings, are inade solid and laid as a course
but it is not necessary that these should extend through the wall but should only
have sufficient tailing to keep them in position until the concrete tilling-in has set.
Gables, pediments, and the like are built up in the same way as. the walling and
steps are left which are filled-in with solid masonry (in the same way as described.
for openings) or Slabs are cast by a simple arrangement of the mould to the

page_text: required angle and a coping, as shewn in figs: 26 and 27, is fixed thereon. We
construct roofs of concrete (asphalted or tarred) or of wood and cover them with
slates or tiles or in any other way. The fixing of lead work such as flashings or
aprons is provided for by the moulding of raglets in the Slabs where they are
required. To facilitate the erection of ornamental chimnies and chimney-stacks,
externally, it is preferable to use a smaller Slab than that used for ordinary con-
struction. Figures VIII and XIII shew the method of making spandril Slabs over
arches whilst arches are constructed in the usual manner, the voussoirs being made
in solid blocks.
IV. Besides the ordinary construction detailed above this system is most
economical for constructing circular work (Fig: 25) and work which is dependent
upon tides such as embankments and also the construction of docks. In circular or
any other form of chimney-shaft we sometimes construct the flue as well as the
outside of the shaft, of these Slabs whilst in some cases we employ fire bricks for
the flue lining. One especial feature of the Slab is that for tidal work it may be
fixed in position for any length of time before the filling in is done (in these cases
the Slabs are made heavier), thus enabling it to be used in the construction of
coffer-dams, sea or dock walls et cetera. We also employ them for the construction
of lighthouses, fortifications, tanks, silos, retaining walls, windmills, Gasometer and
other wells, and gunpowder magazines.
V. The advantages claimed for this system of Building construction are:-
a. It enables concrete to be used alone in every kind of work both domestic and
public without placing so many restrictions on the rules of art as heretofore and
without infringing the rules of sound building construction.
b. The face of the work may be finished (with or without mouldings) as the
building proceeds and there is no liability of the surface to crack and peel off, as in
cases where the face is finished after the structure is raised; or the face of the work
may be left rough or treated in any other way to form a key for plaster if such is
desired. Provision for fixing joinery may also be made by inserting Slabs made
with breeze and such materials for a matrix.
c. It possesses all the advantages of a concrete structure over stone, brick or
such materials and at a reduced cost and is an improvement on present methods,-
dispensing with the use of considerable building plant.
d. The shell of the structure may be built up to practically any number of
courses and the concrete may be filled-in at any convenient height,-
-a great
advantage where, for experiment, the effect of a building is desired to be seen before
great labour has been expended, as by this means the same result is achieved at a
less cost.
e. Cavities or passages for ventilation, electric lighting or any other purpose may
be easily formed during construction.
f. Circular work both on plan or elevation (see Figs: 25. VI. and VII) may be
constructed at a very small cost above plain work and in some cases (Fig: 29) even
cheaper.
g. A cheapening of the cost of certain kinds of heavy engineering and acceleration
in the rate of erecting structures.
h. An excellent system for constructing dock walls as the water may be entirely
prevented from penetrating the joints of the work.
i. The Slab may be manufactured in any plastic material which afterwards
hardens as well as in any solid material which can be worked to the required shape,
or may be a composition of both and it possesses the advantages of being easy of
transportation and manipulation as well as the non liability to cast or warp in a
green state.
j. Structures may be built partially of brick or any other building material
combined with these Slabs. In making additions to the thickness of old walls no
cutting is required. The Slabs are merely fixed in front of the old wall and the
filling is put in between the Slabs and the wall, the latter having been well damped

page_text: with water. The same system of employing only one facing of Slabs to the work
applies to retaining walls, walls for Railway platforms and such like.
VI. We claim as our invention:-
(1.) The peculiar form of Slab herein described, or any modification thereof,
which may be manufactured in a plastic material possessing the properties of
hardening, or in a solid material or partly of both.
(2.) The method of manufacturing and using this Slab and the particular use of
indiarubber, in forming undercut work in concrete described herein as well as the
principle of connecting the Slabs by means of a cement.
(3.) The special methods which I have described of forming (a) footings for
walls; (b) chimney flue gatherings; (c) sets-off; (d) copings to gables; (e) concrete
ceilings and floors; (f) fixings for joinery; (9.) and of applying mouldings and
other ornamental work to the face of structures in concrete.
(4.) The application of concrete and other Slabs to curvilinear construction
(domies; cones; vertical or horizontal cylinders) and also to the construction of
Pyramids.

page_text: Improvements in the Form of Building-slabs for Concrete
Construction and the Method of Manufacturing and
Using the same.
CONSTRUCTION AND THE METHOD OF MANUFACTURING AND USING THE SAME and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :—
This invention is described under the following headings :-
A. A description of the slab.
:-
B. A description of the mould employed for, and the method of, manufacturing
the slab.
T. A description of the different forms and modifications of the slab.
A. A description of the methods of using the slab and a description of the
- special constructions consequent thereon.
E. A description of other than ordinary kinds of work, to which this system is
especially applicable.
Z. The advantages of this system of concrete construction over those already
in use.
H. The invention claimed.
A. The slab may be formed wholly of concrete or any other suitable material, or
combination of suitable materials. In order to convey a clear idea of its form, it
may be said (in the technical terms of Joinery) to resemble a rectangular piece of
one-and-a-half-inch two-panelled framing, flush one side, sunk square, and flat the
other side. Instead, however, of its being sunk square (i.e at an angle of 90°), it
is sunk and undercut at about an angle of 60°. In the top and bottom edges of
the slab, at a distance equal to exactly a quarter of its length from each end, are
formed mortices, or (preferably called) key-holes, generally of dovetail form, having
the smaller sectional area at the entrance of the hole; those in the upper edge of
the slab not quite extending through (what would be called in the technical
language of Joinery) the rail, whilst those in the bottom extend right through the
(so called) rail until they meet the panel, where one of their sides is approximately
flush with, and forms an extension of, the plane of the panel. These key-holes, as
well as being of a dovetail form and of the section shown, may be of cylindrical
or any other form and section, provided they be pierced in an oblique direction.
We do not, however, confine ourselves to any particular form of hole so long as
the required key is obtained. In the edges of the slab, equidistant between the
face and back, runs a groove which encircles the whole slab. That portion of
the groove in the upper edge of the slab occurring between the two key-holes is
preferably not made of an even depth but is made deeper as it approaches each
koy-hole and its shallowest portion, which is of the same depth as that encircling
the slab, is exactly midway between the two key-holes. [The purpose for which

page_text: this is designed will be explained under the heading A:] The inner edges of the
(50 called) framing are, as mentioned above, undercut and appear of dovetail form
in either a horizontal or vertical section through the slab. We do not, however,
confine ourselves to this sectional form but employ upon the inner edges of the (so
called) framing any form of sinking or projection that will give a suitable key-hold
to the mass, of concrete behind the slab, such as moulded projecting studs,
projecting beads (or reeds), sunk circular recesses, hollows and such like.
The form of slab generally used is that of a rectangle and the dimensions found
to work-in to the best advantage are twelve inches high by eighteen inches long
and one and a half inches in thickness. Wo do not however, restrict ourselves to
the rectangular form nor to these dimensions but manufacture and uso slabs of
rhomboidal, triangular, and hexagonal form as well, or indeed of any form that will
give a complete surface when they are combined; and we manufacture them to any
dimensions that may be found to be of the greatest practical utility.
Figure 1 sheet IV, shews in orthographic projection, the roctangular plain slab:
a is the face, b the back, o the key-holes, and d the groove (deeper at e).
Figure 2 sheet IV, shews the slab of hexagonal form.
For slabs of special form see heading, with which are included all, except the
simple slab.
'
B. For moulding the slabs we employ a metal frame, figure 5 sheet IV, having
rigid sides the angles of which are incapable of alteration. The inner surfaces of
this frame are accurately planed and linings (a, B, Y, and 6) of hard vulcanized
india-rubber or other suitable material preferably with a thin face of soft rubber
or such like material, are so fitted to these surfaces that they may be withdrawn
with the slab when it is cast. These linings are manufactured of such a section
that they may give the required form to the edges of the slab during the process
of moulding. The lining &, forming the upper edge of the slab, has connected to
it, arrangements e for forming the key-holes in that edge; these consist of india-
rubber socks of the same external form as the key-hole and are fitted on to
projections from the internal face of the lining as shewn at ¢ A back, or bed, 7,
fitting the metal frame, is inade to enter it from the underside and to touch tho
linings, which are made of less depth than the sides of the frame. This bed,
made of wood or metal, with a covering of a material to which cement will not
adhere, or wholly of metal or other suitable substances, has arrangements 6, by
which the frame is securely fastened to it during the process of moulding the slab,
in order to prevent its jumping up and down, consequent upon jarring the mould.
Soft indiarubber cores, for forming the undercut portion of the back of the slab
as well as the key-holes in the lower edge of the slab, are laid upon the bed and
connected therewith by dowels. Only the portions of these cores forming the
undercut work need bo of indiarubber, the remainder being made of any material
to which cement will not adhere.
In order to manufacture a plain slab, the back, or bed, 7, is first put upon the
bench, the frame λ is then put over it and, extending only for a short distance
down the edge of the bed, is held securely in that position by the fastenings 0,
which prevent the frame from slipping down entirely over the bed. These
fastenings are released when the slab bas become sufficiently hard, in order that
the bed may eject the slab from the rigid frame. The linings a, B, Y, and ô, aro
next inserted in the frame and extend down to the bed, upon which they are made
to rest. The soft indiarubber backs, or cores, i, are then secured in the required
positions, by means of dowels, to the bed. In securing these cores care must be
taken to see that the projecting portions к, forming the key-holes in the lower edge
of the slab, are properly connected with the tongue on the linings by means of tho
groove for that purpose, and that the centres of these projecting portions coincide
with quarter divisions of the length of the slab, which is the position of the key-
holes. The mould is now ready for the operation of casting a slab. The concrete,
mixed in the proper proportions is next deposited in the mould and the mould is

page_text: then jarred in order to liberate the air from the concrete and to cause the concrete
to take, without flaws, the form of the mould. The face is then finished-off by
floating, trowelling or otherwise. If, however, it is desired to ornament the slab in
any way such as by the addition of mouldings, these, having provision for a
suitable key and separately worked or moulded beforehand to the required forms
and lengths, may be inserted in the plastic slab which is then finished-off to them.
Facings of any other material besides concrete are applied in a similar way, whilst
the slab is in a plastic state, and when the slab has become hard, form with it, one
solid mass. As soon as the slab has properly set the bed 7 is disconnected from
the frame at the fastenings 8 and the slab with the linings, is forced out of the
rigid metal frame λ by pressing it down over the bed 7. When the slab and
linings are quite clear of the frame, provided the slab is hard enough, the linings
may be removed. In the proper course of things the cores; and the socks K, left
in the key-holes in the upper edge of the slab, should next be removed, but as the
frame and linings are removed from the slab whilst it is in as green a state as
possible, the cores and socks are allowed to remain until the slab is thoroughly
hard in order to prevent the arrises from being broken away. Finally the slab is
removed from the bed and the cores are taken out. The operation is repeated
de novó for as many slabs as are required, the mould and its parts being always
kept perfectly clean.
г. Figures 2 and 3 sheet II and figure 4 sheet IV, are quoin-slabs of the same
type as the plain slabs described under heading A, the rectangular slab measuring
thirteen-and-a-half-inches one way, and four-and-a-half inches the other, and of
the usual height, whilst the hexagonal slab is divided in the centre. These slabs
are made for internal (figure 3) and external (figure 2) angles and of both hands.
It will be observed that the rectangular slabs give half-slab bond and that the
key-holes of all the quoin-slabs occur at the angle.
Figure 2 sheet I, shews slabs used in the construction of a 9″ and 131″ chimney
jambs, four-and-a-half inches one way by nine inches the other.
Figures 4 and 9 sheet I are illustrations of squint-quoin-slabs for internal and
external angles.
Figures 1 and 2, sheet V, shew slabs circular on plan and on elevation, the
drawings of which will be sufficiently explanatory. These are used in the
construction of cylinders.
Slabs used in the construction of domes are shewn in figure 3 sheet IV. Those
for cones (including of course truncated cones, such as some forms of chimney
shafts) would be of a somewhat similar shape, with the exception that the curvature
would be in one direction only instead of two.
For the construction of pyramids, the quoin-slabs are made to return at the
required batter and the straight portion of the work is done with the ordinary
slabs.
The slabs used in the construction of ceilings and floors are shown in figure 1
sheet II and figures 1 and 2 sheet III. It will be seen that the groove round the
edge of the slab is replaced by a rebate; that the key-holes are dispensed with;
and that the rails of the (so called) framing are channelled-out in the form of a
dovetail to enable them to be keyed to the iron joists by which they are suspended.
Only about two-thirds the number of slabs composing the ceiling are channelled-
out in this way: in the remaining one-third part these channels are omitted.
Slabs for forming sets-off are also shewn in the drawings figure 3 sheet V and
are manufactured in the same way as slabs with mouldings upon their face, as
before described.
Figure 4 sheet II shews the form of slab used for inserting corbels into the wall,
Ornamental forms of the slab are shewn in figures 5, 12 and 13 sheet I.
A wall-base-slab for a quoin to a thirteen-and-a-half-inch wall is shewn' in
figure 8 sheet I, that for the straight portion of the work being continued in the
same way as that for the returned portions. Besides this form of wall-base-slab,
which is used to gauge the thickness of the wall as well as to start the slabs, we

page_text: employ another form which may be used for any thickness of wall and which is
shewn in figures 3, 7 and 11 sheet I. This latter form does away with the
necessity of manufacturing them for specified thicknesses of walls [Their uses
will be described under heading A.]
Figure 1 sheet I shews the method of leaving a provision for the subsequent
bonding of a wall into work which has already been built. The slab occurring at
that part of the work is made thicker than the rest and provided on its face, with
a dovetailed recess which gives sufficient bond to the future wall.
Special slabs are made to which joinery may be fixed, in lieu of the use of wood
blocks or slips. Their form, however, does not differ from that of the ordinary
slab but the aggregate used in their composition is such as to allow nails to be
driven into the slab.
The slab itself may be modified in several ways to suit different classes of work.
Where necessary for certain kinds of work, especially heavy engineering, the
groove round the edge of the slab may be omitted or in lighter work, for the sake
of convenience, portions of the groove may be omitted, or, as in the case of ceiling
slabs, the groove may be replaced by a rebate. Instead of using two keys in the
upper and two in the lower edge of each slab, one only may be used or in certain
cases, both may be altogether omitted: e.g. the hexagonal slab may be built up
without keys of any kind, but in that case the grooves are necessary to prevent
the slabs from being thrust outward, by the pressure of the béton; whilst in the
case of the rectangular slabs the groove may be omitted and the keys retained.
Key-holes may also be formed in the vertical edges of the slab by which they
may be joined together to form the faces to lintels over fire-place openings as
shewn in figure 6 sheet V.
In all the special forms of slab mentioned under this heading we do not confine
ourselves to any particular method of manufacture except in those cases where
modifications of the mould described herein may be employed.
A. To construct a building by means of these slabs, the trenches are first
excavated in the usual manner and the concrete forming the footings is deposited
between boards, or casings of any other suitable material, as shewn in figures 4, 5,
and 6, sheet V. The footings having been brought up to the required height, either
form of the sole-slab, or wall-base-slab, described under heading I, is next accurately
levelled and set upon the footings-In case the wall-base-slab shewn in figures 3,7
and 11, sheet I, be used it may be found necessary to deposit a layer of concrete
between that laid on the inner and that on the outer face of the wall as well as
bedding them, in order to give greater stability to the shells of the structure. If
the aggregate of which the concrete is composed be of a porous nature, such as
burnt clay, an asphaltic or other damp-course is used between the wall-base and
the footings. If however it be of gravel or any other non-porous material, no
dainp-course is required-The first course of slabs is next placed in position upon
the wall-base, the vertical joints of the slabs being laid breaking with the vertical
joints of the wall-base, and the key-holes in each coinciding. Into the key-holes is
poured a quick-setting cement, preferably a bituminous such as "White's hygeian
cement," which is allowed to set and securely hold the first course of slabs to the
wall-base. In case it is desired, for any reason, to do away with the use of a wall-
base, we employ slabs of greater thickness than those ordinarily employed, for the
first course, and these, as well as being bedded upon the footings, may be further
secured by a deposition of concrete between those forming the inner and those
forming the outer face of the wall. The first course having been properly laid, the
courses above are continued in the way described hereafter. We prefer, however,
to use the wall-base, as it ensures better and more accurate work.
The second course of slabs is laid upon the first course, with the vertical joints
of each breaking and the key-holes of each course coinciding, a quick-setting
cement is poured into them in the same way as described for the bed joint between
the wall-base and the first course. Thus are the courses connected to each other.
As we do not restrict ourselves to any form of key-hule neither do we restrict

page_text: ourselves to any method of filling the key-holes to connect the courses together.
As well as filling the holes completely with a cement, we employ dowels made of
any suitable material and these having been dipped into a bituminous or other
cement, are inserted in the key-holes. Another method we employ is to temporarily
insert metal dowels, or rods, and to withdraw them when they can be dispensed
with. These dowels extend vertically through the slab (or part of the slab) of one
course into that below. The portion of the groove (in the centre of the slab)
between the keys will have been filled in with a portion of the cement poured into
the key-holes, by reason of the groove having been made deeper there; the remaining
portions of the groove encircling each slab may be filled with a grout of portland
cement. The groove, when filled, acts as a joggle-joint does in masonry and also
prevents the plastic béton from oozing through the joints of the work and running
down its face.
The filling between the slabs may be done at any period of the work according
to convenience, except where sets-off occur, when it is necessary to fill-in up to
them in order to support the weight of the slabs above.
In forming openings, the jambs (figure 10 sheet I), head (figure 6 sheet I) and
sill are first moulded or worked, from the building material employed, to the
required form and to the height of each course and then fixed in position with the
vertical ends of the slabs butting against them, the grooves in the ends of the slabs
coinciding with similar grooves worked or moulded in the masonry for the purpose
before described. The jambs, and sometimes the head, are further recessed or are
made with projections by which the béton is enabled to get a good key-hold upon
the masonry and securely bond it to the monolith. Chimney-openings and flues are
formed in the way shewn in figure 2 sheet I, where c represents the casings for
forming the opening. The centering for forming the flue-gather is shewn in figure 7
sheet V; pipes, or a core, are employed to form the flue itself. It will be observed
that slabs are not used to face the béton where the roughness of the face formed by
casings is of no practical disadvantage. The lintel over the chimney-opening may
be constructed of slabs of the usual form but having also key-holes in their vertical
edges, as beforementioned. A sufficient number of these being keyed together to
span the opening, they are connected with the lower course, forming the jambs, in
the usual manner and the centering for forming the flue-gather, shown in figure 7
Bheet V, being fixed, the béton is deposited between the slabs forming the face of
the lintel and those forming the outer face of the wall. Lintels of any form, or
indeed arches, may also be used for this purpose. If necessary, in certain kinds of
work, we apply the mantel-jambs and shelf and frieze to the elabs forming the
chimney-jambs and breast, in the same way that we apply mouldings or other
ornament to the slabs, (before described herein). In the lintels, jambs, and sills of
window-openings provision may also be made for ventilation and cores or pipes
may be inserted in the walls in connection therewith. For the purpose of carrying
floors, sets-off are formed (8. figure 1, sheet III), or corbels are inserted in the walls,
or openings may be left in the walls for the insertion of joists, in the same way as
shewn for inserting corbels, figure 5 sheet II. The joists may be inserted before
the béton is deposited between the slabs or else dummies may be then inserted to
be afterwards replaced by the joists themselves. The special floor and ceiling
construction shewn in figure 1 sheet II and figures 1, 2, and 3, sheet III, may be
described thus:-A continuous row of the slabs p (figure 2 sheet III), having a
dovetailed chase in each of them for that purpose, are first keyed to the lower
flange of each iron joist o by means of a bituminous or other cement and the
combination is then fixed in position, with a space of 3 feet from centre to centre,-
the edges of the slabs adhering to (or rather supported by) the iron joists o being
rebated on their edges so as to receive and support an intervening row of slabs 9
(likewise rebated), having the dovetailed chase omitted and the heading joints of
which are laid to break with those supported by the joists. For the construction
of double floors, as shewn in figure 1 sheet III, the iron joists are preferably made
with a double flange on their lower edge (in this case the top flange may be omitted)

page_text: and are fitted to iron girders (figure 3 sheet III) which cross in the opposite
direction to themselves. The provision of a double flange secures the covering of
the cross girder on its underside, by the ceiling slabs. The béton r is then deposited
to the required depth, upon the slabs forming the ceiling and having been allowed
to set, forms a solid floor and finished ceiling. The upper surface of the floor may
be finished-off in any of the usual ways. In case an ornamental ceiling be required
the slabs forming it are prepared beforehand in any of the ways described herein
for the walls. With this system of constructing floors the corbelling (in case the
floor is to be supported upon corbels) may be made in the form of a continuous
moulding and to appear as a cornice in the chamber beneath the floor. This cornice
may be applied in one of the several ways beforementioned herein.
Courses of masonry may be inserted in any portion of the work but crae
should be taken to provide koy-holes for fixing the slabs occurring above the
courses.
Roofs as well as being constructed in the ordinary way, may also be constructed
in the same way as described herein for floors (and if necessary, a curvature may be
given to the ironwork supporting the slabs) and the walls of the structure may be
built up to suit the work. If necessary a blocking-course or any such device
consequent upon certain forms of roof, may be formed of the slabs.
Raglets for flashings may be formed in the slabs employed above the roof.
The method of forming gables and copings to gablos is sufficiently explained by
the drawing, figures 4 and 5 sheet III; a plan of the underside of the coping-stone
being shewn in figure 5, whilst figure 4 is a vertical section taken through the
coping parallel with the face of the work.
E. The classes of work that come under "other than ordinary work" are the
following:-
1. Circular work on plan and elevation, or cylindrical construction, as in curved
roofs,
2. Domical construction.
3. Conical construction, including truncated cones.
4. Pyramidal construction, such as spires and shafts upon a polygonal or square
base, and also battering walls.
1. The slabs having been moulded to the necessary curve and the wall-base also
(supposing one is to be used), the walls are built up exactly in the same way as for
straight work. In cases where the plan of the work is entirely circular it can be
constructed with less difficulty than straight work. Instead of forming square
quoins it is also less difficult to form a bull-nosed angle (figure 8 sheet V) in this
system. Under this heading would come such constructions as circular towers,
certain kinds of chimney-shafts, linings to gasometer and other wells, circular wards
for hospitals, curvilineal roofs, et cetera.
2. Figure 3 sheet IV shews our system of domical construction. The slabs
having been moulded to the required form and thickness, with a curvature in two
directions, and the wall-base also having been moulded to the exact curve. of the
plan, the latter is first accurately laid level at the springing height of the dome.
The dome is built up with an inner and an outer shell, a section of which is shewn
in the drawing figure 3 sheet IV. The inner shell is, preferably, first built up
course by course from either the inside or the outside (each ring of the shell being
made complete before another course is commenced) in the same way as described
for the ordinary walling except that a template with a plumb-line attached, or other
suitable arrangement giving the necessary inclination of the slab, is used to determine
its position in fixing. The scaffold upon which the work is done (supposing it to
be done from the outside) may be suspended from the projecting portions of the
backs of the slabs forming each course of the inner shell, these having been made
of suitable strength for that purpose. The inner shell having thus been completed,
the outer shell is next commenced and the béton is deposited between the shells, as
the courses of the outer shell are built up. If, however, we find it advantageous
in any case, we carry up the inner and outer shells of the dome together. The

page_text: uppermost point of the dome (supposing no opening is to be left) is finished by
inserting circular slabs, one in the inner and one in the outer shell, the latter being
inserted after the béton. If, however, an opening is to be left, a kerb is fixed and
against this the shells finish as in vertical construction. It will have been observed
that the upper courses of the outer shell of the dome in figure 3 sheet IV, are
inclined at a very low angle to the horizon and in consequence, it is almost
impossible to key the courses of slabs to each other by means of bituminous coment,
as before described. In lieu of connecting the courses of slabs in that way, we
employ dowels inserted in the lower key-holes of the slabs to be fixed, connecting
them with those in the upper edge of the course below them. These dowels are
preferably made tapering to fit the hole and with their lower ends notched, or
nicked, in order to give a key-hold to a small quantity of cement deposited in the
lower hole, which may be of dovetail form. These dowels support the lower edge
of the slab. The upper edge is supported by a blocking from the inner shell of the
dome, which blocking when replaced by the béton (having become hard), may be
removed. Before the slab is put in position the groove of the lower course and the
groove in the lower edge of the slab about to be fixed are filled with neat cement
and a small quantity is also placed in the key-holes of the lower course. When the
slabs come together at the bed-joint, the cement in the groove of each is united
and thus forms a similar joint to that obtained in the ordinary way. The dowels
inserted in the key-holes become fixed by the cement surrounding them. The
courses of slabs inclined at a low angle being thus fixed, it only remains to deposit
the béton behind them, which in this case, is preferably done course by course until
the top of the dome is reached.
3. Conical construction is effected in the same way as domical but is much more
easily done by reason of the slabs having a curvature in one direction only.
4. Pyramidal construction is somewhat similar to conical, the only essential
difference between the two being that attention in setting has only to be paid to
the quoin-slabs (which are moulded to the required batter), the others being
regulated by them; whereas in cone construction the attention is directed to each
slab to see that it is of the proper batter.
Z. The advantages of this system of concrete building construction over those
already in uso are :—
1. It gives more freedom in the art treatment of concrete than heretofore without
in any way infringing the rules of sound construction.
2. It provides more economical methods of construction, especially for curvi-
linear work.
3. It produces a better finished structure than heretofore at a smaller cost.
4. The face of the work (whether ornamental or plain) may be completely
finished as the structure proceeds and not left, as is the usual method in concrete
construction, until the building is erected. This also applies to the special method
of constructing floors and ceilings.
5. It avoids the restrictions at present placed upon concrete construction by
supplying additional colours, in the form of thin facings of other materials as terra-
cotta, marble et cetera, applied to the surface of the slab, besides the few in which
concrete has heretofore been manufactured.
6. The heavy expenses often incurred in the alteration of structures in course of
erection may be almost avoided, as in this method of construction (viz: the
building up of a great number of courses of the shells without the filling) will give
the effect of the building and may easily be altered when only the slight expense
of fixing the slabs has been incurred.
7. The walls are kept thoroughly dry and moisture is prevented from penetrating
the face, first by the material of which the slabs are made and secondly by the
method of jointing the slabs. This advantage is specially seen in the application
of this system of construction to dock-walls.
8. The formation of cavities, channels, or passages in the walls for ventilation,
gas, water, electric-lighting, or other purposes, may be. easily effected by the

page_text: insertion of cores or pipes in the béton, and these may be further renderea
complete by the formation of openings, circular or otherwise, with covers formed
of the same material as the surface of the wall and having a frame of metal with
suitable fastenings, fitting into another frame fixed in the wall
9. Provision for fixing joinery may be made at any part of the structure without
inserting wood or other blocks or slips as in the ordinary methods.
10. Where running patterns upon slabs or tiles are used for decorative purposes
this system provides a means of accurately matching the patterns and setting them
flush when they are fixed.
11. Provision for the subsequent bonding of new work into an existing concrete
structure is provided for in a very effective manner.
12. By the use of these slabs thinner walls than those ordinarily built of concrete
slabs can be erected.
«
13. Curvilinear structures may be built more economically than at present,
14. The form of the slab facilitates its transport.
H. Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is
(1.) The peculiar forms of slab herein described or any modification thereof that
may be manufactured in a plastic material possessing properties by which it may
become hard, or in a solid material, or partly of both: all as before described herein.
(2) The application of thin-facings, mouldings, or other ornament in concrete or
any other material, to the face of the slab during the process of manufacture and
whilst it is in a plastic state so that when it has become hard, they form with the
slab, one solid mass. We are aware that hitherto blocks of concrete (and other
building material) have been fabricated at one operation with ornamental faces,
with facings of different materials, and with mouldings upon their faces; we .do
not therefore claim the manufacture, at one operation, of blocks (skeleton or other-
wise) of concrete having mouldings or other ornament upon their face; but what
we do claim is the application of facings, mouldings, and other ornament, made
beforehand of concrete or any suitable material, to slabs of concrete whilst the slab
is in a plastic state, which mouldings et cetera form, when the slab has become
hard, a permanent ornament to its face. All as before herein described.
(3.) We are also aware that slabs, tiles, and blocks, for use in concrete. con-
struction, have been wholly made of such materials as terra-cotta and other clay
ware as well as concrete itself, and that slabs, tiles, and blocks of certain materials
have been faced with certain other materials, and further that designs in coloured
gravel, stones, tiles, glass, and other material, have been made to form a facing to
concrete tiles, slabs, and blocks. We do not, therefore, claim any of these but we
claim exclusively as our invention the facing of concrete tiles or slabs with thin
facings (or slabs) of marble; granite, and such igneous rock; terra-cotta and other
clay ware; porcelain; slate; gypsum; Keenes and parian cements (hydraulically
compressed or otherwise); productions from furnace slag, from waste sand, and
from other silicious substances; all either in their natural or artificial state; in the
manner herein before described.
(4.) The methods of manufacturing this slab, particularly the use of soft india-
rubber, or any substance possessing similar properties, for forming undercut work
in concrete, as well as the use of thin facings of soft indiarubber for the lining of
moulds, and the system of sliding the linings out of the mould with the slab. All
as described herein.
(5.) The method of using this slab as interpreted by the following:-Hitherto
the great difficulty in constructing concrete walls of concrete and other slabs, has
been to prevent the slabs from being forced outwards or from toppling over by the
pressure of the plastic filling-in material (or béton) from the time of its deposition
between the slabs until it has become hard enough to form with the slabs, a solid
wall. Besides the system of forming the slabs of L (vertical or horizontal) section,
or with a kind of internal buttress and shoring them up from the outside, or of

page_text: supporting the slabs upon framing fixed against the faces of the wall, several
devices have been used to obviate this difficulty.
First. Temporary ties, or gauges, connecting together the slabs forming the two
faces of the wall, have been used and as soon as the plastic béton has become hard
(but not before), these have been removed.
Second. Permanent ties, or cramps, have been used and as their name implies,
have been allowed to remain in the wall and to be entirely buried in the plastic
filling-in material. These permanent transverse ties have been of two kinds, those
which were affixed as soon as the slabs were placed in position, and those which
were made to form part of the manufactured slab, as for instanco slabs (really
skeleton blocks) of Zor H, horizontal section.
And third. A small portion of the plastic filling-in material itself has been made
to act as a transverse tic, in the form of a layer deposited in a plastic state between
the slabs of every course and allowed (before the remaining part is filled-in) to set
and thus connect together the slabs forming each face of the wall,-a suitable 'hold
on the slabs in some cases, being given to the tie by a portion of the slab against
which it is deposited being made rough or with dovetailed lugs et cetera.
slabs in this latter system generally have comparatively wide bases, they may also
be bedded or jointed in cement and, provided temporary ties, or gauges, be placed
across their upper edges to connect the slabs forming each face of the wall, together,
the space between thein may be filled-in with the béton.
As the
All these devices, however, are not of permanent utility; they are only tem-
porarily required (i.e. up to the time that the béton has become hard and forined
a permanent transverse tie between the faces of the wall), for it is manifest that
the object of slab-concrete-construction is:-
a. To retain and mould the plastic concrete used in forming the wall;
b. To key or fix the slabs to the mass which they themselves have moulded; and
c. To form a facing to the wall.
When these objects shall have been accomplished there is no further need of any
tie whatever, beyond that which naturally obtains in a concrete wall.
In the systems hitherto adopted (excepting, perhaps, supporting the slabs upon
framing; where the slab alone is not used "to retain and mould the plastic
concrete used in filling "), transverse ties of some kind have been used for every
course. In our system, however, where the slabs are keyed course to course and
are thus prevented from toppling over, any kind of transverse tie to each course, to
be used during the process of construction (except that sometimes used in the
starting course of each structure and that used in inclined slab construction), is
entirely dispensed with and the courses of slabs above may depend solely upon the
courses of slabs below them for their stability and rigidity up to the time that
the plastic filling-in has been deposited and become hard between both faces of
the wall.
There is, however, in addition to this a more decided difference between our
system and those already in use and it is marked by the fact that the slabs
composing the shells of the whole structure, in many cases may be built up before
the filling-in is deposited between the slabs, and in none of the other cases of true
sinb construction can this be done. In fact, only in the "first" and "second
above mentioned can more than one course of slabs be laid before filling-in of some
kind must be done and even in these cases, if due regard be paid to stability, ouly
a limited number of courses can be built up without being filled-in.
"
cases
We therefore claim as our invention in building vertical concrete walls of slabs,
the entirely doing away with the necessity of using any kind of shoring to the
slabs from without the wall, and also doing away with the use of transverse ties to
each course during construction and up to the time that the béton, or plastic
concrete, deposited between the very slabs themselves, shall have become hard and
thus formed a natural tie between both faces of the wall by keying the slabs to its
mass. We effect this by keying the courses of slabs together at their bed joints or,
instead of making the bed joints level, by bonding one course into the other and

page_text: joggling them together, as in the case of slabs of hexagonal, rhomboidal, and other
forms. All as herein before described.
We are aware, however, that the same ultimate result may be attained by having
a bed joint of a sufficient depth to give stability to the slabs and then bedding
them in mortar or cement, but in such a case the slabs must become either
(1) blocks, or (2) skeleton blocks, or (3) what is the same thing as using blocks,
only one course can be built up at a time; and we except these three latter from
our claim.
(6.) The application of concrete and other slabs to curvilinear construction in
concrete and especially to constructions of domical, conical, and pyramidal form;
all as described herein.
(7.) The special methods we have described of forming:-(a) footings for walls;
(b) chimney-flue openings (notably the omission of slabs where a finished face is
not required); (c) sets-off; (d) copings to gables; (c) concrete ceilings and floors;
(f) fixings for joinery; (g) and of jointing the slabs together. All as hereinbefore
described.