Project Ideas

TB86
TILE INSTALLATIONS WITH GROUT JOINTS LESS THAN 1/8-INCH
WIDE
Technical Bulletin
Technical Services 800-282-8786
custombuildingproducts.com
Traditionally, tile or stone grout joints measuring more
than 1/8" wide were filled with a grout including an
aggregate – sand. Grout joints less than 1/8" were
filled with a “non-sanded” grout and 1/16" was the
smallest joint recommended for tile installations.
Today’s advanced grout formulations grouts such as
Fusion Pro® Single Component® Grout, Prism® Color
Consistent Grout and CEG-Lite™ 100% Solids
Commercial Epoxy Grout provide additional options
for small grout joints. This is due to their finer and more
variably-sized aggregates such as glass, limestone or
sand. Now, most grout joints greater than 1/16" can
also be filled with one of these products containing
aggregates.
There are exceptions and limitations and a mockup of
the tile installation will confirm suitability of the grout for
the project. Here are some types of tiles that may still
require use of a grout without aggregates, such as
CUSTOM’s PolyBlend® Non-Sanded Grout.
Polished stone, bisque, metal and other soft tile types
Sand and other aggregates may scratch and
permanently damage the tile surface during the grout
installation. This may be a consideration in hot weather
when grout can dry prematurely during cleanup and
aggressive scrubbing can increase the force of the
sand abrasion. Always perform tests prior to grouting
to determine if the grout will scratch the tile.
Lugged or self-spaced tile types
Tiles with preset spacing or lugs on their edges, such as
commonly available subway tiles, may have 1/16"
spacing when stacked in straight patterns. However,
the joint is reduced to 1/32" when stacking these tiles in
a broken joint/brick pattern. This is due to the rounded
edges and lugs not lining up; the joint width is actually
smaller or has very little depth where the spacing lug
and tile edges make contact. Grouts with sand or
glass will only fill the top 1/32" or less of the joint and it
will be difficult or impossible to place the grout and
finish it correctly. Grout strength and durability is also
compromised as very little grout is actually placed in
the joint. Aesthetically, the appearance of these joints
is unacceptable and often referred to as a “fuzzy joint”
due to the exposed sand and aggregate particles.
Chamfered edged stone or tile
Stone and other tiles that have a slight chamfer are at
times placed with a 1/16" spacing, the minimum joint
width requirement. As in the case of lugged tiles, the
chamfered areas may not support a grout with
aggregates and cracks will occur. The grout will have
to be finished to the top of the joint only and cleaned
away from the chamfer in the installation process.
Rectified and square-cut edges should be selected
when flush filled joints are the desired look for the
installation.
For questions about grouts and grout joints, contact
Custom Building Products Technical Services
Department at [phone] or email
[e-mail].
The information in this bulletin is presented in good faith, but no
warranty, express or implied, is given nor is freedom from any
patent in as much as any assistance furnished by CUSTOM with
reference to the safe use and disposal of its products provided
without charge. Custom Building Products assumes no obligation or
liability therefore, except to the extent that any such assistance shall
be given in good faith.