19th Century Techniques. Aside from the use of improved
tools and modern materials, installation methods have changed
little since the mid-19th century. M. Digby Wyatt, an architect
for one of the major 19th century encaustic tile manufacturers
in Britain, Maw & Co., described this procedure for laying
encaustic and geometric tiles in 1857:
First, either an even layer of bricks, a 2-1/2" bed of concrete
of quicklime and gravel, or a mixture of Portland cement and clean
sharp sand was laid to prepare a solid foundation for the tiles.
If the tiles were to be laid over an existing wooden floor, the
floor boards had to be pulled up, sawn into short lengths and
fitted between the joists. Concrete filled in the spaces and
made the base flush with the upper face of the joists, and created
a level surface finished within 1" of the finished floor
line. A layer of cement mortar was then laid on top. This allowed
the tiles to fit in the same amount of space as the floorboards
they replaced.*Before laying the tiles, skirting boards
or shoe moldings were to be removed, and replaced after the tiles
were laid. This eliminated having to cut the outer tiles to fit
exactly, and resulted in a neater appearance.
Next, the floor design was marked off with mason's string or chalk
lines which divided the space into equal quadrants. The first
section to be laid out was defined by two parallel strips of wood,
or guide pieces, about 4" wide. A level thickness of cement
was spread between these strips. The tiles, thoroughly soaked
in water, were laid in the cement and leveled with a straight-edge.
The foundation had to be kept wet while the tiles were being
laid. Small strips of wood temporarily placed at right angles
to the guide pieces helped keep elaborate patterns straight.
When the bed was hard, the joints were filled with pure cement
mortar-sometimes colored with lamp black, red ochre or other natural
pigments-mixed to the consistency of cream. Excess mortar was
wiped off the tiles with a piece of flannel or sponge.
A newly-laid tile floor could not be walked on for 4-6 days until
the cement hardened properly. Occasional washing would remove
the saline scum that often appeared on the surface right after
the tiles were laid.
20th Century Techniques. Almost 50 years later, in 1904,
the Tile Manufacturers of the United States of America published
Suggestions for Setting Tile with the intent of bringing
tile-laying up to a uniform standard. This guidance was very
similar to that given by Wyatt. But, there were some differences,
such as using hollow clay tile as a foundation material and heavy
tar paper when laying tile over a wooden floor to protect the
floor boards from the moisture of the mortar mix. Emphasis was
placed on using the best quality cement, sand, and purest water
to obtain a durable tile floor. Soaking the tiles before setting
was no longer necessary, but using stiffer mortar was suggested
to prevent it from rising up between the tiles.
"Preserving Historic Ceramic Tile Floors" an Historic Preservation Brief
