Improvements in Slabs for Building and like Purposes.
Year: 1895

page_text: Date of Application, 4th Oct., 1895
Complete Specification Left, 4th July, 1896-Accepted, 8th Aug., 1896
PROVISIONAL SPECIFICATION.
Improvements in Slabs for Building and like Purposes.
I, GUSTAV DE BRUYN, of 48, Hirschgraben, Hamburg, in the German Empire,
Architect, do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in slabs for building and like purposes.
Building slabs made of plaster have been hitherto laid and set by having mortar
applied to their two adjacent ends and then being placed in position in the same
manner as bricks are laid and set. By using this method it is very difficult to set
the slabs correctly and perfectly vertical as the mortar hardens so quickly that the
slabs cannot be moved after being placed in position without injuring the joint.
Attempts have been made to remedy these disadvantages by forming the ends of the
slabs with grooves or flutes adapted to be filled with the mortar the unfluted portions
of the surface serving to support and fix the position of the slab.
This arrangement has, however, the disadvantage that the mortar, which must be
placed in the grooves or flutes before the slab is placed in position as the said grooves
cannot be got at from the outside after the slab has been placed in position, does not
dry quickly enough because air cannot come in direct contact with it. The operations
of setting, and of spreading mortar on, the slab must therefore proceed simultaneously
for the reason that the grooves are not open to the exterior and when placing the
slabs in position the disadvantage, mentioned with regard to the first method, is
present.
Now it is the object of the present invention to remedy this and to this end I
provide the ends of the slabs, which are to make the joints, with a groove or recess so
arranged that it can be got at from the outside and that the said slabs can be placed
in position and set perfectly vertical before mortar has been spread on the same, that
is to say, when they are still quite dry. The mortar can be applied to the joints when
the wall or other structure is partly or completely built up. My improved arrange-
ment has the advantage that the application of the mortar is quite independent of the
laying of the slabs, whereby the said slabs can be laid perfectly, and that the mortar
when applied is uncovered at the outer side as is the case with ordinary brickwork so
that air has free access to the same. By this separation of the two operations and
the setting of the slabs before the introduction of the mortar a great amount of
labour is saved amounting to 100% over that necessary when using the ordinary
grooved slabs.
As moreover the setting of the slabs can be accomplished very accurately it is
not necessary to plaster the wall or the like for papering purposes as it can be
papered without preparation.
In carrying out my invention I provide the slab with a groove or recess at the top
of the right half (looking at one face of the slab) the said groove extending preferably
through half the thickness of the slab and with a second groove in the upper half of
the right hand end of the slab which groove is continuous with the first groove and
extends to the same depth through the slab. I further form a groove or recess at the
bottom of the right half of the slab similar to that formed in the top and also a groove
at the upper half of the left hand end of the slab similar to that formed in the right
hand end. The opposite face of the slab is grooved in the same way except that the
grooves are formed in the reverse position so that the grooves of the two faces shall
not come opposite to and lead into one another.

page_text: When employing the slabs for building a wall, for instance, those of each horizontal
row are similarly arranged but the slabs for the different rows are alternately reversed
in such a manner that the grooves in the bottom halves of the slabs of one row come
opposite those in the top of the next lower row.
By this means spaces are formed in the wall or the like which are adapted as above
described to be filled with suitable mortar. The mortar is always uncovered at one
side so that it can easily and quickly dry and the slabs become very strongly united
by reason of the alternate arrangement of the joints.
The grooves are preferably tapered towards the interior of the slab but they may be
made parallel or tapering towards the exterior.
I sometimes form the slabs without grooves on their bottom faces but in this case
the grooves in the top faces are made correspondingly deeper so that the strength of
the horizontal joint remains practically the same as before. This modification has the
advantage that each row can be set perfectly vertical over the preceding row with
slabs of the same height as the above described slabs.
The arrangement of the grooves can be modified so as to form spaces of different
shape for the mortar, for instance, straight and rectangular. It is also not necessary
that the grooves should extend to the centre of the slabs as they can extend
further than the centre or the different grooves of each slab can extend to different
depths.
A very suitable material for the manufacture of my improved slabs is chemically
prepared plaster of Paris and ashes with suitable light additional materials. The
mass is poured into a mould in a fluid condition the mould being preferably made of
iron so that the slabs may be formed with as sharp angles and as flat surfaces as
possible. Instead of plaster and ashes other suitable material, such as, for instance,
cement could be used.
Dated the 4th day of October 1895.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Slabs for Building and like Purposes.
I, GUSTAV DE BRUYN, of 48, Hirschgraben, Hamburg, in the German Empire,
Architect, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :-
This invention relates to improvements in slabs for building and like purposes.
Building slabs made of plaster have been hitherto laid and set by having mortar
applied to their two adjacent ends and by then being placed in position in the same
manner as bricks are laid and set. By using this method it is very difficult to set the
slabs correctly and perfectly vertical as the mortar hardens so quickly that the slabs
cannot be moved after being placed in position without injuring the joint. Attempts
have been made to remedy these disadvantages by forming the ends of the slabs with
grooves or flutes adapted to be filled with the mortar, the unfluted portions of the
surface serving to support and fix the position of the slab.
This arrangement lias, however, the disadvantage that the mortar, which must be
placed in the grooves or flutes before the slab is placed in position as the said grooves
cannot be got at from the outside after the slab has been placed in position, does not
dry quickly enough because air cannot come in direct contact with it. The operations
of setting, and of spreading mortar on, the slab must therefore proceed simultaneously
for the reason that the grooves are not open to the exterior, and when placing the
slabs in position the disadvantage, mentioned with regard to the first method, is
present.

page_text: Now it is the object of the present invention to remedy this, and to this end I
provide the ends of the slabs, which are to make the joints, with a groove or recess so
arranged that access can be had to it from the outside and that the said slabs can be
placed in position and set perfectly vertical before mortar has been spread on the
same, that is to say, when they are still quite dry. The mortar can be applied to the
joints when the wall or other structure is partly or completely built up. My improved
arrangement has the advantage that the application of the mortar is quite independent
of the laying of the slabs, whereby the said slabs can be laid perfectly, and that the
mortar when applied is uncovered at the outer side as is the case with ordinary brick-
work so that air has free access to the same. By this separation of the two operations
and the setting of the slabs before the introduction of the mortar a great amount
of labour is saved, amounting to 100% over that necessary when using the ordinary
grooved slabs.
As, moreover, the setting of the slabs can be accomplished very accurately it is
not necessary to plaster the wall or the like for papering purposes as it can be
papered without preparation.
To enable my invention to be fully understood I will describe it by reference to the
accompanying drawings, in which :-
my
Figure 1 is a perspective view of a slab made according to invention:
Figure 2 is an elevation of a portion of a wall built with my improved slabs:
Figure 3 is a section to shew the shape of the grooves or recesses in the slabs:
Figure 4 is a view similar to Figure 2, the slabs being slightly modified:
Figure 5 is a cross section of the same.
Referring to Figures 1, 2 and 3, the slab is provided with a groove or recess a at
the top of the right half (looking at one face of the slab) the said groove extending
preferably through half the thickness of the slab to the median plane x-x and with a
second groove b in the upper half of the right hand end of the slab, which groove b is
continuous with the first groove a and extends to the same depth through the slab.
I further form a groove or recess c at the bottom cf the right half of the slab similar
to that formed in the top and also a groove d at the upper half of the left hand end of
the slab similar to the groove b formed in the right hand end. The opposite face of
the slab is grooved in the same way except that the grooves are formed in the reverse
position so that the grooves of the two faces shall not come opposite to and lead into
one another. This is clearly shewn in Figure 1.
When employing the slabs for building a wall, for instance, as shewn in Figure 2,
those of each horizontal row are similarly arranged but the slabs for the different rows
are alternately reversed in such a manner that the grooves a in the slabs of one row
come opposite the grooves a in the next row and so that the groove 6 of each slab
comes opposite the groove d in the adjacent slab, as clearly seen in Figure 2.
By this means spaces are formed in the wall or the like which are adapted, as
above described, to be filled with suitable mortar. The mortar is always uncovered at
one side so that it can easily and quickly dry and the slabs become very strongly
united by reason of the alternate arrangement of the joints.
The grooves are preferably tapered towards the interior of the slab, as shewn in
Figure 3, but they may be made parallel or tapering towards the exterior.
1 sometimes form the slabs without grooves on their bottom faces as shewn in
Figures 4 and 5, but in this case the grooves in the top faces are made corrc-
spondingly deeper so that the strength of the horizontal joint remains practically the
same as before. This modification has the advantage that each row can be set
perfectly vertical over the preceding row with slabs of the same height as the
above described slabs.
The arrangement of the grooves can be modified so as to form spaces of different
shape for the mortar, for instance, straight and rectangular. It is also not necessary
that the grooves should extend to the centre of the slabs as they can extend further
than the centre or the different grooves of each slab can extend to different depths.
A very suitable material for the manufacture of my improved slabs is chemically
prepared plaster of Paris and ashes with suitable light additional materials. The

page_text: mass is poured into a mould in a fluid condition, the mould being preferably made of
iron so that the slabs may be formed with as sharp angles and as flat surfaces as
possible. Instead of plaster and ashes other suitable material, such as, for instance,
cement could be used.'
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. Slabs for building and like purposes, having their edges provided with grooves
or recesses adapted to receive the mortar after the slabs have been placed in position,
substantially as, and for the purpose, hereinbefore described.
2. Slabs of the kind described in Claim 1 wherein the grooves or recesses on the
two faces are reversed in position with respect to one another as described.
3. The improved slabs for building and like purposes hereinbefore described and
illustrated in Figures 1, 2 and 3 and 4 and 5 respectively.
ed the 4th day of July l
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.