Why is My Client’s Grout Turning Yellow?
By Frederick M. Hueston, Stone Forensics
Over the years I have received many calls from stone
and tile restoration professionals asking how to identify the cause of grout
yellowing and resolve grout yellowing problems. The reasons for this
discoloration are many. Testing can help determine what is causing the problem.
Solutions vary, depending on the cause. Here are the details.
Top Ten Reasons for Grout Yellowing
1. Shampoos,
soaps, etc. – Many of the personal items your clients use contain chemicals
that can cause discoloration, and hence yellowing of grout. This is especially
true of hair dyes and shampoos that contain coloring agents.
2. Body
oils – Skin and hair oils contain many contaminants that can cause
discoloration of not only grout but also tile. These body oils are what cause
the familiar yellow stain, ring-around-the-collar.
3. Sealers
and waxes – Sealers and various waxes can contain polymers that can discolor over
time and cause yellowing.
4. Grout
types – There are numerous grout types that are prone to yellowing. White epoxy
grouts are notorious for turning yellow.
5. Cleaning
products – Certain cleaners, especially those that contain dyes, can cause
discoloration of grout. Household bleach commonly discolors grout.
6. Iron
– Certain water supplies contain iron. Water containing iron can deposit
minerals on the grout that can oxidize and cause a yellow discoloration. If the
water used to mix the grout during installation contained iron this can also
cause discoloration. Check your water supply for iron.
7. Dirty
water – Water used to mop floors can rapidly get dirty. The dirt, oils, etc.
will settle on the grout lines and cause a yellow cast. Encourage your client,
or the cleaning or janitorial services they use, to keep mop heads clean and
change mop water often.
8. Smoke
– Cigarette smoke can settle on grout lines, causing the grout to turn yellow.
9. Aerosol
sprays – Sometimes aerosol sprays, such as hair sprays and even air fresheners,
cause grout discoloration.
10. Bleed
over – Certain tile types, such as white marble, contain iron. Iron from the
tile can bleed into the grout and oxidize, causing the grout to turn yellow.
How to Test for Yellowing
As mentioned above, there are many reasons why grout
can turn yellow. Here are some suggestions for inspecting the grout to
determine the cause:
1. Determine
what cleaning products and toiletries have been used in the area. Look up the
SDS on the product to determine whether products contain dyes, polymers, or
other ingredients that may cause grout to turn yellow.
2. Test
the grout lines for iron using a product from Alpha Tools called RSR 2000.
Place a small dab on the grout and wait several minutes. If it turns purple, it
is positive for iron.
3. Test
the water for iron if iron oxidation is suspected. Test kits can be purchased
at most home centers or water supply stores. If iron is present in the water, suggest
that your client install a water filtration system.
4. Try
to determine the grout type. Epoxy grout can be problematic.
5. Take
a knife and scrape the grout. Examine the scraped area to see if the
discoloration is on the surface or all the way through. Surface discoloration
usually indicates chemical discoloration.
Once the cause of grout yellowing is determined, you
can attempt to resolve grout yellowing problems. Be sure to instruct your
client about using preventative measures such as discontinuing the use of
stain-causing products, smoking outside, installing a water filtration system,
etc.
How to Clean Yellowed Grout
To clean yellowed grout, you will need sulfamic acid,
which can be purchased at most home centers and can also be found at most tile
supply companies, and a good floor wax stripper, which can be purchased at most
janitorial supply houses. Ask for an alkaline-based floor wax stripper. Caution:
Sulfamic acid will damage marble surfaces.
Here are cleaning instructions:
1. Sweep the floor thoroughly, removing any loose
dirt, dust, etc. For showers and walls, wipe with a dry rag.
2. In a cleaning pail, mix warm water and a good floor
cleaner or ammonia. For showers and walls, use a clean rag and for floors, use
a clean mop to clean the grout. Empty the pail.
3. Next, mix alkaline stripper with warm water, being
sure to follow the directions on the bottle.
4. Apply a small amount of this solution to the grout.
Allow it to stand for several minutes. Agitate the solution with a scrub brush,
toothbrush, or similar type brush. Apply additional solution if the grout
begins to dry.
5. Pick up any excess solution with a mop or a wet
vacuum.
6. Rinse the grout with plain, warm water. Empty the
pail.
7. Mix sulfamic acid with warm water, per the directions
on the label.
8. Apply the acid solution to the grout and agitate.
9. Rinse the grout several times with clean water and
allow to dry overnight.
10. Once dry, seal the grout with a good penetrating
sealer.
If the above technique does not work and the grout is
in good condition and not falling apart, then apply a high-quality grout color
sealer. As a last resort, remove and replace the grout.
