Failure Number 7 Concrete Slabs Without Discontinuous
Capillary Pore Structure.
Expansion joints! Expansion Joints!
Expansion joints are mandatory to
allow the stone assembly including the stone, setting materials, grout and
adjacent restricting materials to accommodate moisture and thermal
Requirements for expansion joint
Minimum ½ inch joint with maximum
spacing at 16 feet apart in all directions;
Minimum 3/8 inch joint with maximum
spacing at 12 feet apart in all directions;
Minimum ¼ inch joint with maximum
spacing of 8 feet apart in all directions;
Minimum 1/8 inch joint with maximum
spacing of 4 feet apart in all directions.
These rules include all
installations on exteriors of buildings, all installations exposed to sunlight
or temperature changes, and all installations exposed to moisture.
We recommend doubling the rule for
interior applications and caution exceeding these rules.
In addition, expansion joints are
required where tile and stonework abut restraining surfaces, such as perimeter
walls, dissimilar floors, curbs, columns, pipes, ceilings, handrails,
doorframes, and where changes in backing material occur.
Expansion joint through tile and
stone installations over structural joints must never be narrower than the
All expansion, control,
construction, cold and seismic joints in the structure should continue through
the tile and stonework including all horizontal and vertical assemblies.
For additional information consult
the Handbook For Ceramic Tile Installation, Published by the Tile Council of
America, Assembly Method EJ171.
The expansion joint detail has been
the center page of the handbook for the past 20 years however was relocated in
The failure of the installing tile
and stone contractor to coordinate and install or have installed by other
contractors the correct expansion joints to these requirements and the
specifications, contributes to the most failures that occur in California on
commercial and institutional projects.
In addition, we are observing large
custom homes with no expansion joints and resulting loss of bond of flooring
assemblies. The lack of expansion joints
is exacerbated by the lack of scarifying the concrete slab prior to