Generally, you should be okay to mix up some grout and touch up any trouble spots in your new grout. Stuff like pin holes, scratches or low spots can be touched up with fresh grout the next day. The trick is to blend in the new grout with the old so make sure you mix it the same way that you mixed it the day before.
ANSWER. ANSWER - It is possible to grout over existing grout if there is enough depth to do so. 1/8 inch depth may or may not be adequate depending on the type of grout used. A latex modified grout may work, but you have to properly clean the existing grout to ensure the new grout adequately bonds.
However, you must make sure you are re-grouting with the same type of grout you originally used. If not, the second layer will not adhere well to the first and you will have to do the same job over again in a few months' time.
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.
The shortest time after laying tile that you can grout is 24 hours. However, it is much better to wait at least 48 hours before grouting. This is to give the mortar ample time to set and dry before pressure is applied. Choose a nice and dry day to lay your tile.
Unsanded grout is the other type of cementitious grout. And, like sanded grout, unsanded grout typically takes up to a full 72 hours to cure. You'll also need to apply a penetrating sealer when using unsanded grout in a bathroom. Epoxy grout, made by combining a hardener with epoxy resin, takes just 24 hours to cure.
New grout can take 24 or even 48 hours before it dries completely. It depends on the humidity and temperature in the room where the grout is installed.
It is important to wait until the grout has set in before wiping the tiles clean, as premature wiping can result in gouges. However, don't wait too long, or the grout will dry onto the tiles, potentially causing irreversible damage.
Optimally, no more than 30 minutes should pass for the initial wiping off of excess grout. This process must be performed gently with a wet grout sponge during regrouting. Once the grout application is complete and excess grout removed, there will be a second waiting process.
The main cause for this variation in color is uneven drying of the Portland cement in the grout. There are jobsite conditions and factors which create the conditions for uneven drying and improper cement hydration.
Use a shop vacuum to thoroughly remove dust. Use the wand attachment on the shop vacuum to get into the crevices. Then clean the grout with bleach or a mildew remover to remove all traces of mildew. Rinse and dry until there is no standing water in the joints, but try to leave joints slightly wet before you grout.
There are two ways you can change the colour of your grout. You can either remove the old and replace it with new, or you can dye your existing grout. The latter will only work if you currently have light grout and you want to dye it darker.
STEP 6: Let grout rest (slake) for up to 10 minutes.
Allow the grout to “slake,” the term for letting it rest for five to 10 minutes so that the chemicals can bond.
Make sure your tile surface is completely dry before you attempt to remove any haze. This typically takes about 24 hours. Consult your installation professional—or, if you DIY-ed it, your grout's packaging—for the exact amount of time. But do not wait more than 10 days to remove grout haze.
Once the grout has started to harden (20 to 30 minutes), begin sponging. Don't use just any sponge, especially one from the kitchen; choose a “hydrophilic” sponge. Make sure the sponge is damp, not wet, and sweep diagonally across the face of the tile and wipe the grout off the tile surface.
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.
This results from a few key causes: Exposure To The Elements. A common problem for wet areas in the home, like the bathroom or shower, grout tends to crack here as a build-up of water slowly eats away at the material. General Wear and Tear From Traffic.
Even if the grout appears to be hard, achieving the correct color will require time for excess moisture to evaporate. We know you've been looking forward to seeing your finished product, but don't get ahead of yourself! We recommend waiting for at least 48 hours after installing a grout before you apply a sealer.
Grout Must Set and Cure
That usually takes between 48 and 72 hours. If you can avoid walking on your floor for that amount of time, that would be ideal. Once the grout is fully cured, you can walk on your new tile flooring with no concerns about damaging it or causing tile pieces to shift.
You'll want to wait at least 24 hours before taking a shower so the new seal has time to set. Consider testing your seal by spraying water against your new grout. If some parts of the grout absorb the water, you may want to revisit that spot later on.
The standard cement grout commonly found in most hardware stores and used in most residential homes takes around 48-72 hours to cure. But it is worth pointing out that you need to know how to mix grout the right way. If too much water is added it will obviously take longer to dry and won't do its job as well.