As with cementitious grouts, do not overmix or mix too quickly.
Grout is often mixed or worked improperly, with too much water which washes the pigment out. It's written on the bag. The type of water used can also cause problems if there are a lot of minerals in your water. In that case, I believe they can use distilled water.
The grout, once mixed, should readily stick to the end of a putty knife. When you grab a glob of grout from the mixing bucket, it should not droop off the putty knife. If the grout is runny and can be poured like a milkshake, too much water has been added.
Myth #2 - Just add water! Adding a bit more water will get more working time with your grout. Excess water weakens your grout mixture. If water is added to “stretch out” the working time of your grout, it changes the structure of the mixture.
The only way to rectify this problem is to scrape out the grout and to completely replace it – which can be done by using a grout rake or remover. Once the joints are clean, apply the correctly-mixed grout.
Under certain circumstances, a white powder can form on grout, especially on floor tiles. This is a natural phenomenon called efflorescence. It is due to soluble salts rising to the surface of a cement based product. When they dry out on the surface, the remaining salts appear white and powdery.
The abrasive and alkaline effects of wet grout can be very hazardous to the eye. Exposure to airborne dust or wet grout may cause immediate or delayed irritation of the eyes. Depending on the level of exposure, effects may range from redness to chemical burns and blindness.
Soak a piece of wire wool in warm water and then rub it over the grout you want to remove. You can also use a chemical grout stripper, although this should be your last resort as it can damage your tiles. Test it on an inconspicuous area first to make sure it doesn't etch or stain your tile.
The ideal grout (both sanded or un-sanded) looks stiff but has a creamy consistency as you can see in the image below. We recommend using a Margin Trowel (mixing trowel) for mixing grout. When you mix the grout with a margin trowel, you'll know the grout is ready when it looks like this.
However, a common guideline is to wait approximately 15 to 30 minutes after applying the grout before wiping off the excess. This initial waiting period allows the grout to firm up and achieve a workable consistency.
Step 4: The Slake and Final Mix
Once you're pleased with the consistency, let the grout mixture sit, or “slake,” for about 10 minutes.
You can apply new grout right over the top of the old grout. To do this, all you need is a grout removal tool. Use the tool to strike out the old grout, making sure the depth is at least 2mm, which is about the thickness of two dimes stacked one on top of the other.
Check the color and condition in some of the higher-traffic areas of the room. If you notice any chipping or cracking in the grout, it won't respond well to cleaning and will most likely just break apart if you try to clean it with any kind of physical force.
The consistency of grout should. resemble smooth peanut butter. It should be malleable but not dripping from the trowel when lifted. If the mix. is too stiff or dry powder is visible, add more water.
ANSWER - If you are using a cementitious grout it should harden. If you used too much water in mixing the grout and/or too much water in cleaning the grout during the installation of the grout you can weaken the grout causing it not to harden.
There are a number of factors that can cause cracks and issues in the grout. But if cared for properly, grout can last for up to twenty years.
To remediate this type of problem to make the grout to be more consistent in color there are products called "grout colorants" that are epoxy based and match some of the typical grout colors. After properly preparing the existing grout joint you paint it over the joint which could be a bit tedious of a process.
Acidic Cleaners
Cleaners that have a high chemical pH or are acidic will begin to eat away at your grout and make it more fragile and porous. Stay away from cleaners that contain vinegar and citrus. This will eat away at the top layer of the grout and cause the need for replacing grout lines sooner.
There is always risk when treating the symptom rather than the problem, but if you don't see any other indications of problems then you could re-grout it with the cementitious grout making sure it is done properly the third time, or grout with an epoxy grout that will be more resistant and durable, but is more ...
Have you ever noticed a white powder appearing on the surface of grout and/or tiles in your home? Don't panic, it's efflorescence – a salt deposit left behind as water evaporates from the surface, which isn't harmful but can spoil the aesthetic of your tiles.
You can often remove efflorescence haze from small areas by washing it off with a 50/50 solution of white vinegar and water. For large areas, use a haze remover or sulfamic acid mixture 1. If this is a new tile installation, you must wait 7 days to 10 days before acid washing.