Apart from filling gaps and acting as reinforcement between tiles, grout is also used to enhance aesthetics. That’s why it’s available in multiple colors.
The presence of dark spots on new grouts can be a bit irritating because that’s not the finish you were interested in.
But what causes dark spots on new grout lines? Keep on reading to find out and also learn how you can fix and prevent this problem in the future.
What Causes Dark Spots on New Grout?
1. Dirt Buildup
One of the most obvious causes of dark spots on new grout is dirt buildup. An area that has been freshly grouted needs to be enclosed until the grout fully cures.
If left open, kids or even pets can walk over the grout and stain the freshly applied grout. So, if you’ve noticed dark spots on new grout, find out if your kids or pets were playing in the room earlier.
And next time, make sure to keep that area out of bounds until the grout dries. And that isn’t a very long time because most grouts dry within a day or two.
2. Using Water with High Mineral Content
When preparing grout, you need to stick to clean and pure water. Using hard water may cause discoloration on new grout. Hard water is rich in minerals which may react when mixed with grout.
If the dark spots on your new grout are caused by hard water, the discoloration will be fairly consistent and distributed all over the place.
3. Uneven Pigment Distribution
Sometimes, insufficient mixing of grout can lead to an issue known as uneven pigment distribution. In a bag of grout, the color pigments are usually more concentrated at the bottom. So, if you don’t mix it well, the grout will be a bit darker in some areas.
4. Residue from Other Construction Jobs
Understandably, most construction jobs occur simultaneously. And at times, residue from other things can find its way into new grout and when it dries, that residue could turn into a dark spot.
It’s a good idea to always ensure residue from adhesives or other materials doesn’t find its way into new grout.
5. Forgetting to Seal the Grout
Sealant plays a crucial role in preventing dark spots from forming on grout. Therefore, if you don’t apply a sealant to new grout, there is a huge chance that a spill or dirt buildup will be absorbed and it will turn into a dark spot.
6. Efflorescence
In grout, efflorescence is when water-soluble salts move from the grout and come to the surface to form a grayish haze. On lighter grouts, this grayish haze caused by efflorescence may appear as dark spots
7. Mold
I understand how all homeowners feel about mold. But it could be the one causing dark spots on your new grout. Did you know that it only takes mold 24 hours to grow?
So, as you install new grout, mold may have found its way into the crevices. And after a few days, you may notice some black, green, or red spots.
If you suspect that the dark spots on your new grout are mold, please be very careful when dealing with it. Some mold variants are known to be very lethal.
8. Inadequate Cleaning
An integral part of installing grout is thoroughly cleaning it after installation. If the cleanup is done poorly, that can result in the formation of unsightly dark spots.
How to Remove Dark Spots from New Grout?
Because many factors cause dark spots on new grout, the ideal remedy will depend on what you’re dealing with.
However, the method I’ll be sharing below is used to address most of the issues listed above such as dirt buildup, mold, residue, efflorescence, and inadequate cleaning after installation.
Step 1: Prepare a Cleaning Solution
The first step in dealing with dark spots on new grout is by preparing a cleaning solution. You can use water and vinegar or dish soap.
You don’t need a very strong or harsh cleaner because the grout is fairly new. You’re also going to need a stiff brush and a scraper or a knife.
Step 2: Scrape the Dark Spots
You need to figure out the depth of the dark spot. This is where a knife comes in handy. Dig out the dark spot to identify how deep it is.
If the spot is on the surface, then cleaning it will be much easier. If it’s deep, you may have to consider re-grouting.
Step 3: Dip the Brush into the Cleaning Solution and Start Scrubbing
This is where the heavy work starts. Dip the brush into the cleaner and scrub on the dark spot as hard as you can until the stain disappears.
Don’t be afraid to apply a lot of pressure as long as the grout has dried. You may have to repeat this step at least two times.
Step 4: Mop the Area with Clean Water
Take a clean cloth, dip it in freshwater, and mop the area that you were working on. Make sure that you mop as much liquid as possible.
Then give the cleaned grout enough time to air dry. And that’s it, your new grout will no longer have dark spots.
Please note that, If the dark spots are a result of using hard water or uneven pigment distribution, the best solution here is to re-grout.
Are Certain Types of Grout More Prone to Developing Dark Spots?
There are indeed certain types of grout that are more susceptible to developing dark spots immediately after installation. A good example is light-colored grout.
The lighter the grout color is, the easier it is to stain. So, if you’re installing white or grey grout, prepare to deal with highly visible dark spots.
Also, more porous grout will easily absorb moisture and stains thus leading to the formation of dark spots. It’s best to stay clear of such.
It’s also worth mentioning that grout used in high-moisture areas is also more likely to develop dark spots. Don’t forget to seal the grout because, without this layer of protection, dark spots are inevitable.
Should I Hire a Professional to Remove Dark Spots from My New Grout?
As you can see from the method on how to deal with dark spots on new grout, you don’t need professional help.
The process is relatively easy and with a little bit of elbow grease, you can get rid of dark spots from new grout in minutes.
However, if your grout was installed by a professional tiler and dark spots have developed due to their mistake. You have the right to call them back and ask them to fix this issue for you.
A professional tiler should be aware of the dos and don’ts of grouting. If they used hard water or didn’t mix the grout correctly and now you have dark spots, they should be liable for the repairs.
How Long Should I Wait After Grout Installation Before Address Dark Spots?
New grout is usually very delicate. If you scrub it with a brush, you may end up removing the entire product from the tile gaps.
So, if you have spotted dark spots on the new grout, I’d advise you not to deal with it immediately. Give it a few days, preferably more than three.
This will be enough time for the grout to dry and then you can clean off the dark spots using vinegar, dish soap, and a stiff brush.