IMPROVEMENTS IN ROOFS, PARTLY APPLICABLE ALSO TO FLOORS AND PAVEMENTS
Year: 1873

page_text: LETTERS PATENT to William Alexander Lyttle, of the Grove,
Hammersmith, in the County of Middlesex, Engineer, for the
Invention of "IMPROVEMENTS IN ROOFS, PARTLY APPLICABLE ALSO TO
FLOORS AND PAVEMENTS."
Scaled the 4th April 1873, and dated the 4th January 1873.
PROVISIONAL SPECIFICATION left by the said William Alexander
Lyttle at the Office of the Commissioners of Patents, with his
Petition, on the 4th January 1873.
I, WILLIAM ALEXANDER LYTTLE, of the Grove, Hammersmith, in
the County of Middlesex, Engineer, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN ROOPS, PARTLY APPLICABLE ALSO TO
FLOORS AND PAVEMENTS," to be as follows:-
With the view of rendering the roofs of dwelling and other houses
cheaper, more cool in hot weather, and less likely to catch fire externally,
I propose to construct them flat, and so arranged with relation to the
vent by means of which the rain water is allowed to escape, that by
closing that vent at a point inside the watertight boundary of the roof,

page_text: the water shall completely cover the roof if supplied in sufficient
quantity. By this means neither sparks nor flame can ignite or heat the
roof, and the spontaneous evaporation will suffice to render the rooms
next the roof deliciously cool in summer.
Instead of simply plugging the escape water pipe above referred to by
inserting a solid plug or other stopper I prefer to insert a short piece of
tubing standing upright, and of such length that when inserted, and the
water has risen to its top, it shall overflow down through it into the
escape water pipe before any has escaped over the watertight boundary
of the roof at the sides or ends of the house. Under this arrangement
the top of the house must be covered with a waterproof metallic or other
sheathing, so as to be exactly similar to a shallow water tank, and when
a constant or frequent water supply can be secured, an arrangement may
be made by a ball-cock or self-acting supply valve, by means of which
the water shall, when desired, be always maintained at the same depth.
A lightning conductor connected electrically with this sheet of water or
wet roof, and also with the earth in the usual way, will act with greater
protective power by reason of the increased conducting surface connected
therewith, and also through the inductive action between the sheet of
water and the thunder cloud overhead.
The waterproof covering of the roof must be carried upward inside the
coping or parapet, and around any skylight and any trap or other door
so far as to prevent the escape of any water, except through the escape
pipe above mentioned.
Any existing description of water-tight arrangement will answer, but
I prefer a roof made with an outer covering of asphalte, and more
especially of the asphalte described in my Letters Patent of last year,
numbered 31, and entitled " Improvements in the Preparation and
Laying Down of Bituminous Asphalte for Pavement."
A roof so constructed can be covered in with a glazed conservatory,
and used as such, with a grated second floor at such height from the
water-tight roof above mentioned as to clear the surface of the water
when the water is laid on. Asphalte being preserved like gutta percha
by being kept covered with water, it will be an advantage, whether the
roof is covered with glass or not, that it be kept covered with water,
which may be used as an aquarium.

page_text: A concrete or cement floor laid on joists with laths or battens, and
covered outside with the asphalte, answers well. Great strength is
imparted to the cement or concrete if it is incorporated with a small
per-centage of blood; the proportion of blood varying from two per cent.
to any greater or less amount according to the fineness or coarseness of
the solid particles of the concrete or cement, as well as its absorbent and
caustic characteristics. In each case the quantity must be found by trial
if the minimum proportion of blood is desired to be used.
Instead of mixing blood with the whole of the concrete it will be
found most economical to lay a stratum of common coarse concrete or
cement in the first instance, and then top this with a stratum of fine
blood cement as described. A concrete bed topped with blood cement
in this way, with or without a thin layer of asphalte on its upper surface,
forms a foundation for wooden block pavement equal to the wooden
boards now laid underneath such pavement, and will serve when laid
underneath granite pavement to prevent its wearing uneven. A
foundation like this also adds largely to the strength of any kind of
asphalte or other paving material.
A very durable and water-tight arrangement of flooring for roofs
consists of a stratum of concrete or cement moistened when set with
dilute glycerine slightly thickened with glue or size, then a thin layer of
very plastic waxy asphalte made according to my above mentioned
Patent. Next on the top of this a thin layer of cement or plaster with
or without admixture with blood, and with or without the application of
glue and glycerine; and lastly, the strong outer layer of asphalte. The
inner layer of waxy asphalte performs the function of the stratum of
puddled" clay used to prevent leakage through the banks of canals.
The solution of glue and glycerine is for the purpose of retaining so
much dampness in the cement as to exclude the air from the waxy
asphalte and so to preserve its plasticity. The intermediate layer of
cement between these two layers of asphalte under this arrangement
may be wetted with "oil of creosote" instead of the glycerine solution.
66
When a granite pavement is provided with a foundation as described
above, it is better at the same time to joint the stones either with fusible
asphalte or with slips or wedges of wood.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Alexander Lyttle in the Great Seal
Patent Office on the 27th June 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ALEXANDER LYTTLE, of the Grove, Hammersmith, in the County of
Middlesex, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourth day of January, in the year
of our Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Alexander Lyttle, Her special
licence that I, the said William Alexander Lyttle, my executors,
administrators, and assigns, or such others as I, the said William
Alexander Lyttle, 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 Inven-
tion for "IMPROVEMENTS IN ROOFS, PARTLY APPLICABLE ALSO TO FLOORS AND
PAVEMENTS," upon the condition (amongst others) that I, the said 2
William Alexander Lyttle, my executors 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 immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said William Alexander Lyttle, 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:-
With the view of rendering the roofs of dwelling and other houses
cheaper, more cool in hot weather, and less liable to catch fire externally,
I propose to construct them flat with a surrounding water-tight parapet,
each roof or convenient section of roofing being provided inside the 3
boundary of the water-tight parapet with a vent hole or valve, from

page_text: which a horizontal vent pipe shall extend into the ordinary vertical
piping outside the house, by means of which the rain water is now
allowed to escape. By closing that vent or valve the water will com-
pletely cover the roof if supplied in sufficient quantity, and by this
means neither sparks nor flame can ignite or heat the roof. The
spontaneous evaporation of the water when it is retained on the roof
will suffice to render the rooms next underneath the roof deliciously
cool in summer.
Instead of simply plugging or otherwise completely stopping up the
vent hole of the escape water pipe above referred to by inserting or
applying a solid plug or other stopper I prefer to insert a short piece of
tubing standing upright, see A, Figure 1, and of such length that when
inserted and the water has risen to its top it shall overflow down through
it into the escape water pipe, shewn in dotted lines B, C, Figure 1, before
any has escaped over the water-tight boundary of the roof at the sides
or ends of the house. The upper surface of the water on the roof is
indicated by the dotted line D, A, E, Figure 1. Under this arrangement
the top of the house must be covered with a waterproof, metallic, or
other sheathing, so as to be exactly similar to a shallow water tank, and
when a constant or frequent water supply can be secured an arrange-
ment may be made by a ball-cock or self-acting supply valve, by means
of which the water shall, when desired, be always maintained at the
same depth. A lightning conductor connected electrically with this
sheet of water or wet roof, and also with the earth in the usual way,
will act with greater protective power by reason of the increased con-
ducting surface connected therewith, and also through the inductive
action between the sheet of water and the thunder cloud overhead.
The waterproof covering of the roof must be carried upward inside
the ordinary or ornamental parapet, see F, G, Figure 1, and around any
skylight and any trap or other door so far as to prevent the escape of
any water except through the escape pipe A, B, C, Figure 1, above
mentioned.
Any existing description of water-tight arrangement, metallic or
otherwise, will answer, but I prefer a roof made with an outer covering
of asphalte, natural or artificial. Of the latter class the bituminous
cement specified in my Letters Patent, numbered 31, of last year, is
specially suitable. The title of this Patent is "Improvements in the
Preparation and Laying Down of Bituminous Asphalte for Pavement."

page_text: A roof so constructed can be covered in with a glazed conservatory
and used as such, with a grating or second floor at such height from the
water-tight roof above mentioned as to clear the surface of the water
when the water is laid on. Asphalte being preserved like gutta percha
by being kept covered with water it will be an advantage under any
circumstances to maintain a constant covering of that liquid on the
roof. If the water is used as an aquarium the growth of the plants will
prevent its becoming offensive through stagnation.
A concrete or cement floor laid on joists with laths or battens in the
usual way and covered outside with asphalte answers well. Greater
strength is imparted to the cement or concrete if there is incorporated
with it a small per-centage of blood, the proportion of the latter varying
from two per cent. to any greater or less amount according to the
fineness or coarseness of the solid particles of the concrete or cement,
as well as its absorbent and caustic characteristics. In cach case the
quantity must be found by trial if the minimum proportion of blood is
desired to be used.
Instead of mixing blood with the whole of the concrete it will be
found most economical to lay a stratum of common coarse concrete or
cement in the first instance, and then to top this with a stratum of fine
blood cement as described. A concrete bed topped with blood cement
in this way, with or without a thin layer of asphalte on its upper
surface, forms a good foundation for wooden block pavement, and will
serve when laid underneath granite pavement to prevent its wearing
uneven. A foundation like this also adds to the strength of asphalte or
other like material used as pavement.
A very durable and water-tight arrangement of flooring for roofs
constructed in accordance with the water tank principle herein-before
described, or for ordinary flat roofs, consists of a stratum of concrete or
cement, A, B, Figure 2, moistened when set with dilute glycerine,
slightly thickened with glue or size, then over this a thin layer of very
plastic waxy asphalte, C, D, Figure 2, made according to my above
mentioned Patent. Next on the top of this the strong outer layer of
asphalte E, F, Figure 2. The waxy layer C, D, may be spread on brown
paper and so laid on the layer A, B, Figure 2, or paper dipped in the
waxy material in question and laid in one or more sheets, superimposed,
may be used as the intervening layer between the strata A, B, and E, F.
These three layers are shewn in Figure 1 resting in the same order on

page_text: the line of boarding K, K', the latter being sustained by the joists M, B, N.
An intermediate layer of common cement or paper may be provided
if desired between these two layers of bituminous cement under this
arrangement, and it may be wetted either slightly with "oil of creosote,"
designated also dead oil of coal, or with the glue and glycerine solution
already described. The object of this arrangement, as well as of the
moistening of the stratum A, B, Figure 2, with glue and glycerine, is to
check both the drying action of the air and to prevent the layer C, D,
becoming hardened in consequence of its waxiness becoming absorbed
or diffused throughout the mass with which it is in contact. This inner
layer of waxy material performs the same water intercepting function
as the stratum of "puddled clay," used to prevent leakage through the
banks of canals.
The water-tight roof constructed as described may be fitted with a
pipe, if desired, leading down into the house, and so furnished with
branches and cocks on each landing or floor that the water on the roof
may be made available for the extinguishing of fires within the house.
When it is intended to keep a constant covering of water on such roofs
it is expedient to form the water-tight lining F, G, Figure 1, of tho
parapet with an inclination outwards, amounting to about 45 degrees or
more from the perpendicular, so as to counteract the outward thrust in
a horizontal plane exercised by water when freezing.
In order to make it possible to lay asphalte or other bituminous
cement, in one or more layers in any desired manner, directly upon a
bottom or backing of boards without an intervening layer of plaster and
without any caulking, "tongueing," or other special jointing of such
boards I propose to cover the joints of such boards by means of thin narrow
strips of metal or hoop iron A, L, B, Figure 3, secured by tacks A, B,
driven close to, but outside, the edge of such strips of metal. The flat
heads of these tacks overlap and so hold down the metal strips whilst
receding from the latter as the wood shrinks, and the metal strips
prevent the bituminous cement or asphalte from sinking into the joints
of the boards and so becoming uneven. This last arrangement is
applicable in the case not only of the water tank roofs herein-before
described but to all flat or sloping roofs covered with asphalte, as well
as to all boarded house floors, and to the wooden boarded decks of
ships, which may be covered upon the upper surface with any kind of
asphalte.

page_text: Having now described the nature of my Invention, and the best means
known to me for carrying the same into effect, those means however
being obviously capable of many modifications, without material
departure from the same general principles, what I claim is,--
Firstly. The construction of water tank roofs upon the principles 5
herein-before described.
Secondly. The use of blood in the substratum of concrete or plaster,
as and for the purpose described.
Thirdly. The use of a waxy intercepting substratum underneath the
outer layer of asphalte or other bituminous cement employed in the 1
covering of roofs.
Fourthly. The use of a mixture of glue or size and glycerine to
prevent the hardening of the waxy intercepting substratum as described.
Fifthly. The closing of the joints of wooden roofing or flooring by
mcans of metallic strips, in the manner and for the purpose herein- 1
before specified.
In witness whereof, I, the said William Alexander Lyttle, have
hereunto set my hand and scal, this Twenty-seventh day of
June, in the year of our Lord 1873.
W. A. LYTTLE. (L.S.) 2