IMPROVEMENTS IN PRODUCING CEILINGS OF PLASTER OR CEMENT.
Year: 1875

page_text: LETTERS PATENT to Richard William Hitchins, of Stoke Newington,
in the County of Middlesex, for the Invention of "IMPROVEMENTS
IN PRODUCING CEILINGS OF PLASTER OR CEMENT.
Sealed the 29th June 1875, and dated the 4th May 1875.
PROVISIONAL SPECIFICATION left by the said Richard William
Hitchins at the Office of the Commissioners of Patents, with his
Petition, on the 4th May 1875.
I, RICHARD WILLIAM HITCHINS, of Stoke Newington, in the County
of Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PRODUCING CEILINGS OF PLASTER OR CEMENT," to be as
follows:-
My Invention relates to improvements in producing ceilings of plaster
or cement, whereby the operations of lathing, pricking up, and floating
are dispensed with, and the time required for the plaster or cement
to dry after each of the two last named operations is economized, as the
foundation or body of the ceiling can be manufactured in advance, and
requires only to be nailed up and finished in the ordinary way.

page_text: By means of my Invention greater strength is obtained, and the
ceiling is less liable to crack and become detached.
My Invention consists in making the body or foundation of the
ceiling in slabs or sheets composed of two layers of plaster or cement,
with a sheet of canvas or other open woven fabric, or a layer of loose
fibres placed between them, a lath being also embedded in the plaster or
cement along two of the opposite edges of the canvas to stiffen the slab
or sheet in its span from one joist to another. The slabs or sheets thus
formed may be of rectangular or other convenient shape, and are nailed
to the joists. The edges of the slabs or sheets are bevelled so as to lap
joint with adjacent ones.
The slabs or sheets are made in the following manner:-A layer of
plaster of Paris in a moist or plastic state is spread evenly on a flat
surface surrounded by raised edges of the form to produce the desired
bevel of the edges of the slab or sheet, and upon this first layer of plaster
is laid a sheet of canvas or other woven fabric of proper size, or a thin
layer of loose fibres, which is made to embed itself into and adhere to
the plaster. Two laths are then laid along two opposite edges of the
canvas, upon which another layer of plaster is spread evenly, and before
it sets a rough broom is passed over the surface of this second layer of
plaster to form a key for the finishing coat. When the plaster is set the
slabs are nailed to the joists, as before mentioned, and the joints are
made good with plaster of Paris. The third or finishing layer of limo
and plaster is then applied to the ceiling in the ordinary way.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 2
filed by the said Richard William Hitchins in the Great Seal Patent
Office on the 4th November 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
WILLIAM HITCHINS, of Stoke Newington, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourth day of May, in the year
of our Lord One thousand eight hundred and. seventy-five, in the
3

page_text: thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Richard William Hitchins, Her
special licence that I, the said Richard William Hitchins, my executors,
administrators, and assigns, or such others as I, the said Richard William
Hitchins, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN PRODUCING CEILINGS OF PLASTER OR CEMENT," upon the
condition (amongst others) that I, the said Richard William Hitchins,
my exccutors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, should particularly describe
and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
:
'NOW KNOW YE, that I, the said Richard William Hitchins, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the accompanying
Sheet of Drawings and to the letters and figures marked thereon, that is
to say:
:-
My Invention relates to improvements in producing ceilings of plaster
or cement, whereby the operations of "lathing," "pricking up," or
"rendering" and "floating" are dispensed with. Moreover, the delay
necessary to allow the plaster (lime and hair mortar) to dry after each
of the two last-named operations is avoided, as the foundation or body
of the ceiling is manufactured beforehand, and requires only to be nailed
up and "set" or finished by coating with a thin layer of plaster or
cement in the ordinary way.
By means of my Invention greater strength is obtained, and the
ceiling is less liable to crack and fall.
My Invention consists in making the body or foundation of the
ceiling in slabs or sheets composed of two layers of plaster or cement,
with a sheet or sheets of canvas known as scrim," or other reticulated
fabric, such as wirework, (or it may be loose fibres) placed between them,
"

page_text: a lath being also embedded in the plaster or cement along two of the
opposite edges to stiffen the slab or sheet in its span from one joist
to another. The slabs or sheets thus formed may be of rectangular
or other convenient shape, and are nailed to the joists. The edges of
the slabs or sheets are bevelled, so as to make a scarf joint with the
adjacent slabs.
The slabs or sheets are made in the following manner :-A layer of
plaster of Paris or cement in a sufficiently moist or plastic state is
spread evenly on a flat surface or table surrounded by raised edges
forming a mould of the proper shape to give the edges of the slab or
sheet the requisite bevel, and upon this first layer of plaster (which may be
about 4th of an inch in thickness, more or less) is laid a sheet or sheets
of canvas or other fabric of proper size, or loose fibres laid parallel and
crosswise to one another,) the same being made to embed in and adhere
to the plaster. Two laths are then laid along two opposite edges of the
canvas, upon which another layer of plaster or cement about a quarter
of an inch thick is spread evenly, and before it sets a rough broom is
passed over the surface of this second layer to form a "key" for the
finishing coat. When thoroughly set the slabs are removed from the
bench; and exposed to the air to dry, after which they are ready to be
nailed to the joists, as before mentioned; the joints between the slabs
are made good with plaster of Paris, and the third or finishing layer of
lime and plaster or cement is then applied to the ceiling in the ordinary
way.
In order that my Invention may be more readily understood I have
illustrated it in the accompanying Drawing, which represents an under
side face view and an edge view of one slab or sheet as nailed to the
joists.
The slab is composed, as before mentioned, of two thicknesses of
plaster or cement a, b, with a sheet of canvas c (shown in red lines)
embedded between them; d, d, are two laths of wood embedded along
two opposite edges to stiffen the slab; e, e, are the ordinary joists, to
which the slabs are attached by galvanized iron or zinc nails f. The
edges of the slabs are bevelled, as shown, so as to partly overlap the
correspondingly bevelled edges of the adjoining slabs y shown in dotted
lines.
Having described the nature of the Invention, and the manner of
performing the same, I declare that what I claim as the Invention to be

page_text: protected
ene nefcine in part recited Letters latent is, the
manufacture of ceilings by making the body or foundation of the ceiling
in sheets or slabs composed as herein described, which are nailed to the
joists and finished with a final coat of plaster or cement, substantially as
set forth.
In witness whereof, I, the said Richard William Hitchins, have
hereunto set my hand and seal, this Third day of November,
in the year of our Lord One thousand eight hundred and seventy-
five.
Joists and unished with a final coat of plaster or cement, substantially as
set forth.
In witness whereof, I, the said Richard William Hitchins, have
hereunto set my hand and seal, this Third day of November,
in the year of our Lord One thousand eight hundred and seventy-
five.
RICHARD WILLIAM HITCHINS. (L.S.).
RICHARD WILLIAM HITCHINS. (L.S.).