Improvements in or relating to Slabs or Blocks for Building.
Year: 1896

page_text: Date of Application, 22nd Feb., 1896-Accepted, 4th July, 1896
COMPLETE SPECIFICATION.
Improvements in or relating to Slabs or Blocks for Building.
A communication from MELCHIOR RAINOLD GIDEON LÖSCHKE and ALEXANDER
OPELT, Manufacturers, of 42 Grunaerstrasse, in Dresden-Altstadt, in the
Empire of Germany.
1, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex
Chartered Patent Agent 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 :-
Slabs, blocks or plates for building purposes, made of plaster with or without
the admixture of other substances such as coal ashes are well known. It is well
known also that they are to a certain degree brittle and fragile.
It is found that the strength of such material can be considerably increased, if
pulp (wood-pulp) is added to the liquid plaster paste (which may contain an
admixture of coal ashes or the like). The quantity of pulp to be added depends
on the circumstances. Where great strength is required (for instance in slabs for
ceilings), the quantity of pulp will be about one tenth of the volume of the other
constituent parts (including the water for mixing); where less strength is required,
the proportion of the pulp added can be smaller. It is found suitable to proceed
in the following manner;-
A sufficient quantity of plaster, water and sifted coal-ashes for a certain number
of slabs or blocks is thoroughly mixed in big troughs. To this liquid paste is
added a certain amount of pulp, mixed with water. The mass is poured into iron
frames or moulds on flat tables covered with a rubber facing (as a support for the
moulds and the material in them) pressed in hard and smoothed with smoothing
tools. The rubber support of the slab can be ribbed to produce on the underside
of this slab a rough surface to take plastering; but of course slabs with a perfectly
smooth surface can be produced by omitting the ribs. After the mass has set, the
slabs are taken out of the frame or mould and preferably roughened on the edges
with a scraper, in order to make the plastering or cement adhere to them when the
joints between adjacent slabs are afterwards filled. The completed plates are
dried in airy drying-sheds between battens for the purpose of preventing
warping.
For the production of 2 square metres of ceiling slabs for instance 10 litres of
coal-ashes, 20 litres of plaster, 22 litres of water and 5 litres of pulp are used;
for one square metre of slabs for walls 20 litres of coal-ashes, 20 litres of plaster,
25 litres of water and 5 litres of pulp are mixed together as described.
The slabs produced in this way are cheap and in spite of their great strength
can be easily sawn and nailed, without fear of breaking pieces from them.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondents and in what manner
the same is to be performed I declare that what 1 claim is ;--
1. A process for producing slabs or blocks of building material, characterised by
the admixture of pulp with this plaster paste mixed with water and other
substances substantially as described.
2. Slabs or blocks of building material of plaster and wood pulp with or with-
out the admixture of other substances.

page_text: 3. For the production of slabs or blocks of building-material a mixture of the
materials described in or about in the proportions herein before set forth with
reference to ceiling slabs.
4. For the production of slabs or blocks of building-material a mixture of the
materials described in or about in the proportions hereinbefore set forth with
reference to wall slabs.
Dated this 22nd day of February 1896.
BOULT & WADE,
Agents for the Applicant.