Structures.
Year: 1889

page_text: Date of Application, 19th Feb., 1889
Specification Accepted, 30th Mar., 1889
Structures.
I CHARLES CARROLL GILMAN of Eldora Iowa in the United States of America,
Manufacturer of Porous Terra Cotta 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 object of my invention is the construction of a cheap and durable asphalt or
cement covered roof, and I attain this object by the construction hereinafter described
and claimed.
The accompanying drawing is a perspective view of a roof embodying my
invention.
Referring to the drawing A represents the wooden rafters, placed preferably, about
twelve inches apart, and owing to the weight imposed they should be three inches
wide. I apply to the outside of said rafters slabs or blocks B of terra-cotta lumber
or a porous burned brick material, which are nailed to said rafters or secured thereto
in any other appropriate and effective manner. Said slabs or blocks should be from
three to four inches thick, about twelve inches wide, and from twelve to twenty four
inches long. I use this material because of its porous structure, which provides
numerous anchorages for the cement or asphalt covering and also because it is to a
very high degree a non-conductor of heat and cold, can be easily sawed or worked
with carpenters tools and will receive and hold nails. I apply to said slabs or blocks
a layer of mastic C made of asphalt, coal tar, or equivalent substance mixed with sand
or gravel or broken limestone. This mastic is rolled over the porous slabs, in the
manner that similar compositions are rolled upon streets and walks and to a depth of
about one inch. Instead of this mastic of asphalt, a layer of cement may be used.
This outer finishing layer of asphalt or cement becomes thoroughly united to the
porous slabs, so that it is impossible to detach it therefrom, protects the slabs from the
action of the weather, and forms with said slabs a roof which is proof against fire
and the action of the weather and prevents the penetration of heat and cold to the
Interior.

page_text: It is evident that the described combination of terra cotta lumber blocks and a layer
of mastic of asphalt is equally applicable to a framework of iron instead of to one of
wood.
I do not desire to limit myself strictly to terra cotta lumber, so called, as any
porous burned brick material having substantially the same properties is within the
scope of my invention.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is :-
-
The combination, with the wooden rafters of slabs or blocks of terra cotta lumber
or its equivalent, laid on said rafters and secured to the same by nails, said slabs
extending from rafter to rafter and a finishing layer of asphalt mastic or its equivalent
spread over the same, said layer adhering tenaciously to said slabs by reason of their
porous character substantially as described.
Dated this 19th day of February 1889.
C. C. GILMAN.
By Brewer & Son,
33, Chancery Lane, London,
Agents.