FAQ

TB21
EFFLORESCENCE ON GROUT
Technical Bulletin
Technical Services 800-282-8786
custombuildingproducts.com
This technical bulletin addresses concerns and
questions about the causes, prevention and treatment
of efflorescence and mineral film discoloration on
Portland cement grout.
Efflorescence can form shortly after grouting, resulting
in a brand-new installation that may look splotched or
completely covered with a white crust or film, to the
dismay of the owner and the installer.
Efflorescence is a mineral deposit that sometimes
leaches or migrates to the surface of the grout. These
minerals occur naturally in Portland cement, which is
present in the grout and many building materials that
come into contact with the tile assembly. Many kinds
of mineral salts have been detected in samples of
efflorescence including sodium sulfate, potassium
sulfate, sodium carbonate, calcium sulfate, sodium
bicarbonate and calcium carbonate.
Additional minerals can also come from the water
used during the installation of the grout or
accumulated on the surface of the grout during
maintenance. Grout mix consistency, environmental
conditions and installation techniques beyond the
grout manufacturer’s control can also influence the
occurrence of efflorescence.
Dense bodied tile such as porcelain, polymer-modified
setting mortar and dense substrates prolong the time
grout takes to become firm before clean-up. Water
mixed with the grout has nowhere to go but out
through the grouted joint, and will carry minerals to the
grout surface. A wet grout mix and/or clean-up before
the grout is properly firm will create the conditions for
efflorescence to occur, especially in cooler weather.
Grout selection can reduce the risk of efflorescence
appearing on your grout. Prism
®
Color Consistent
Grout is formulated with specialized cement that does
not contribute to efflorescence. Fusion Pro
®
Single
Component
®
Grout is a blend of polymers and inert
fillers that does not contain Portland cement and will
not effloresce. By selecting the right grout, the installer
can leave the project knowing that efflorescence will
not appear the next day.
Although unsightly, the mineral deposits can be safely
removed by following a few simple steps.
What to do if you have Efflorescence
In most instances, efflorescence can be removed and
future growth inhibited with Aqua Mix
®
Eff-Ex
®
over
unsealed cement grout. Heavy contamination of
efflorescence salts may require a mild acid wash.
Aqua Mix or TileLab Sulfamic Acid Crystals is a mild,
odorless acid that is intended for use with ceramic or
porcelain tiles that are not sensitive to acid attack.
Aqua Mix Cement Grout Haze Remover may also be
used. Care should be exercised when removing
efflorescence from the grout between natural stone
tiles that may be sensitive to acid etching.
Grout must cure a minimum of 7 days before
attempting to remove efflorescence with an acid
wash. Aqua Mix Eff Ex may be used the following day
of grouting. Follow the manufacturer’s directions when
using any products to remove efflorescence. Always
test in a small inconspicuous area and allow it to dry
completely prior to treating the entire installation.
Never seal grout that is not satisfactory in color,
hardness or appearance. Normal sealers are not
designed to correct a “problem” grout job.
Application of sealers over a problem grout will only
tend to enhance the issue and prevent usage of
simple corrective measures.
Always observe product precautions and wear
appropriate safety equipment. Acid cleaners must not
be used on soft natural stone such as marble,
limestone or travertine installations. Non-acidic
cleaners must be used for these acid sensitive
materials. Contact CUSTOM Technical Services for
recommendations.
Custom Building Products offers a full line of tile and
grout care and maintenance products. Contact the
Technical Service Department at 800.282.8786 if you
have questions concerning these methods or products.
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.
TB21 4/17R