ANSWER:
It is possible to put a thin layer of grout over existing grout, but there are some important considerations to keep in mind. The depth of the existing grout is a crucial factor in determining whether this can be done successfully. In your case, with a depth of 1/8 inch, it may or may not be adequate depending on the type of grout you plan to use.
When considering grouting over existing grout, it is important to choose the right type of grout. Latex modified grout is commonly recommended for this purpose as it offers better bonding and flexibility. This type of grout is designed to adhere well to various surfaces, including existing grout lines.
Before applying the new layer of grout, it is essential to thoroughly clean the existing grout. This will help ensure proper bonding between the old and new grout. Use a grout cleaner or a mixture of water and vinegar to remove any dirt, mildew, or stains. Scrub the grout lines with a stiff brush and rinse thoroughly to remove any residue. Allow the grout to dry completely before proceeding.
Once the existing grout is clean and dry, you can mix the new grout according to the manufacturer’s instructions. Apply the grout to the grout lines using a grout float, making sure to fill in the gaps evenly. Use a diagonal motion to ensure full coverage and push the grout into the spaces between the tiles.
After applying the new grout, use a damp sponge to remove any excess grout from the tile surfaces. Rinse the sponge frequently and continue wiping until the tiles are clean. Be careful not to remove too much grout from the joints.
Allow the grout to dry for the recommended time specified by the manufacturer. Once it is fully cured, you can use a grout sealer to protect the new grout and enhance its durability. Applying a sealer will also make the grout easier to clean and maintain in the long run.
It is important to note that grouting over existing grout may not always yield the best results. If the existing grout is significantly damaged, cracked, or crumbling, it may be better to remove the old grout completely and regrout from scratch. This will provide a more stable and long-lasting solution.
In my personal experience, I have successfully grouted over existing grout in small areas where the depth was adequate and the existing grout was in good condition. However, I have also encountered situations where the new grout did not adhere well to the old grout, leading to cracking and separation over time. Therefore, it is crucial to assess the condition of the existing grout and choose the appropriate approach accordingly.
To summarize, it is possible to put a thin layer of grout over existing grout if there is enough depth to do so. A depth of 1/8 inch may or may not be adequate depending on the type of grout used. Latex modified grout is recommended for better bonding and flexibility. Properly cleaning the existing grout is essential to ensure the new grout adequately bonds. However, it is important to assess the condition of the existing grout and consider removing it completely if it is significantly damaged.