Improvements relating to Plaster Slabs or Composite Boards for Building Purposes.
Year: 1896

page_text: Date of Application, 31st July, 1896-Accepted, 12th Dec., 1896
COMPLETE SPECIFICATION.
Improvements relating to Plaster Slabs or Composite Boards
for Building Purposes.
We, ADOLF MAOK and OTTO MAOK, Manufacturers, of Ludwigsburg in Württemburg,
in the German Empire, 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:-
The present invention has for its object to produco a building material and walls
which are weather-proof and fireproof, besides possessing insulating properties,
strength and cheapness, and which do not require any finishing process such as the
application of brown coats and white coats hitherto necessary for plaster boards.
The plaster boards hitherto found in the market had to be coated with a mixture of
sand, lime and cement, generally called brown coat, or with plaster of Paris, generally
called white coat, in order to obtain a smooth and uniform surface and to render them
damp proof, which operation costs much trouble, time and money.
An attempt has also been made to produce plaster boards having a rough surface,
which surface consists of grit or chips of stone, and which is intended to facilitate the
plastering of buildings; but this kind of plaster slab also requires a white or finishing
coat; moreover, these brown and white coats are frequently detached after a short
time by the influence of the weather, that is to say, by damp air and moisture,
especially in the case of outer walls or in rooms where much dust and steam is
produced.
In conflagrations when the finished surfaces of plaster boards are exposed to
water jets, the coating is apt to come off, thus reducing the resistance of the matorial
to fire.
The new plaster boards or slabs, also called "Mackolith," are made as follows.-
We take a mould similar to those generally used in the manufacturo of plaster
boards, and lay upon the bottom of the mould a board, to which are attached ledges
of indiarubber, so as to form a skeleton into the interstices of which are laid thin
plates of earthenware or other suitable facing. This facing is preferably wedge-shaped
both longitudinally and transversely, so that it will be enveloped by the plastic mass
and cannot separate accidentally from the same. The remaining space of the mould
is now filled with a liquid mortar poured into the same, and wooden laths are pressed
into the mortar in such a manner that they will be situated behind the joints of the
face plates. The wooden laths thus embedded in the mortar not only impart a firm
hold to the plaster board, but greatly facilitate its attachment to wooden lattice work
or beams by means of screws or nails.
The accurate and regular division of the board ensures a uniform surface of the
plaster slabs.
As soon as the mortar has solidified, the plaster slab may be taken out of the mould
and allowed to dry in the air. In a similar manner plaster slabs may be made which
have facing on both sides. In some cases the wooden laths may be omitted, or may
be replaced by wire netting, iron bars, or other devices adapted to strengthen or
stiffen the slab.
The process is applicable, not only to flat plaster slabs, but also to convex or concave
slabs, and to building blocks of various shapes.

page_text: The thin plates of earthenware which constitute the surface or coating of our new
plaster slabs are bad conductors of heat, and materially improve the insulating
properties of the slabs.
The insertion of wooden laths in the manner described increases the strength of the
new plaster boards considerably and facilitates their fixtureto beams or joists, and as
the earthenware facing plates mentioned above need be only a few millimetres thick,
they are much cheaper than a weather-proof plastering or other liquid coating applied
in the usual manner.
The improved plaster slabs or mackolith is applicable in a variety of ways, but
chiefly as a weatherproof and fire-proof insulating outer cover for wooden and iron
lattice work, or as an inner cover in the shape of walls, ceilings and floors which can
be easily washed, which latter is important from a sanitary point of view, especially
for hospitals. It may be used also as a practically indestructible insulating material
for localities with damp air, such as basements, cellars, laundries, dye works and
stables.
In the accompanying drawings,
Fig. 1 is a plan and Fig. 2 a transverse section of a rectangular mould for making
plaster boards according to this invention;
Fig. 3 is a transverse section on a larger scale, showing the mould, together with
the face plates laid within the same, the plastic mineral mass, the laths embedded in
the latter, and the wooden board serving as a temporary base.
Figs. 4 and 5 show three parallel layers or courses of mackolith mounted on
woodwork.
Figs. 6 and 7 show a portion of the same on a larger scale, together with the means
for fixing the mackolith on woodwork; Fig. 7 being a section along line A-B
of Fig. 6.
Fig. 8 is a vertical section showing a method of attaching ceilings of mackolith to
iron joists.
In these figures a represents the mould which should be made of two or more parts,
as is usual in the manufacture of plaster boards; b represents a rectangular network
of indiarubber forming panels for the insertion of face platos; c are the face plates of
ordinary earthenware, terra-cotta, coment, plaster, or other suitable material. They are
bevelled on the sides and provided with dove-tailed recesses in their base. The
thickness may be from one eighth of an inch upward, according to the size and material
of the said face plates.
d represents the plaster or other plastic mineral matter cast into the mould;
e, wooden laths embedded in the plaster; f, the wooden board serving as a base for
the mould; and g, screws for fixing the plaster slab to the woodwork.
In Figs. 4 to 7 each plaster slab does not form a plain rectangle as in Fig. 1, but
has a projection at one end and a corresponding recess at the other, in order to inter-
lock with the contiguous plaster slabs. The letters m, n, o, p, q, r in Fig. 7 indicate
the outline of a plaster slab.
In Fig. 8, A represents iron joists or girders, B a ceiling of mackolith, and C a
wooden floor.
Owing to the great solidity and lightness of mackolith, and to the wooden slabs
embedded in it, mackolith is suitable also for temporary structures, such as exhibition
buildings, and the slabs can afterwards be screwed off and used for other purposes.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. A plaster slab or composite board for building purposes provided with thin plates
of earthenware or other suitable facing material embedded into the plastic mass as a
substitute for the application of a brown coat or a white coat, and with wooden laths
to increase the stiffness or strength of the slab and to facilitate the use of fastening
screws or nails, or with wire netting, iron rods or similar substitutes, substantially as
described and for the purpose specified.

page_text: 2. The manufacture of plaster slabs or composite boards in the manner substantially
as described.
تيمم
1
FAIRFAX & WETTER,
433, Strand, London, Agents.