What will dissolve old grout?

Over time, grout can become discolored, cracked, or just generally worn down. Old grout not only looks unsightly, but it can also allow moisture to seep into crevices and cause damage. Fortunately, there are several methods available for dissolving and removing old grout, making way for fresh new grout. This article will explore the most common and effective solutions for dissolving and removing old grout.

Why Does Grout Need to be Replaced?

There are a few key reasons why grout may need to be dissolved and replaced:

• Discoloration – Grout can become stained or change color over time due to moisture, grime buildup, or simply from age. A once white grout line can fade to yellow or brown.
• Cracking/Crumbling – Normal wear and tear can cause grout to crack, crumble, or develop holes and divots. This not only looks bad, but can allow water to seep behind the tile and cause damage.
• Unsightly Repairs – Attempts to patch or repair grout lines with a mismatched color can leave the grout line looking splotchy.
• Change in Taste – Sometimes grout is replaced to simply update to a new color or style preference.

Replacing old, worn grout creates a like-new appearance and prevents potential water damage behind tiles.

Dissolving vs. Removing Grout

When tackling an old grout replacement project, you have two main options – dissolving the existing grout or completely removing it:

Dissolving Grout

Dissolving grout involves applying a chemical solvent to the existing grout lines to soften and disintegrate the old grout. Once dissolved, the grout can be scraped out and washed away rather easily. The benefits of dissolving over removing include:

• Less time consuming than removing entirely
• Less risk of damaging the underlying tiles
• Smaller grout lines may be difficult to fully dig out

Removing Grout

Removing grout entails fully digging, scraping, and chiseling out the old grout lines. The benefits of complete removal include:

• Ensures all old grout is eliminated before re-grouting
• Allows inspection of the tile edges and underlying surface
• Wider grout lines and badly damaged grout may need to be fully removed

So in summary, dissolving grout is quicker and lower risk for smaller grout lines in relatively good condition. Completely removing grout can provide a more thorough clean slate for significantly damaged or wider grout lines.

Best Chemicals for Dissolving Grout

If opting to dissolve old grout, these are some of the most common and effective chemical solvents:

1. Sulfamic or Phosphoric Acid-Based Grout Removers

Sulfamic and phosphoric acid are the key active ingredients in many popular grout removers. Products containing these acids help soften and disintegrate old cement-based grout. They provide a relatively easy and low-mess option.

Key tips when using sulfamic/phosphoric acid grout removers:

• Check product suitability for your grout type.
• Pre-wet the grout lines.
• Apply a thick layer of the product and allow 5-10 minutes of dwell time.
• Reapply if needed for stubborn areas.
• Rinse thoroughly.
• Use caution and proper skin/eye protection.

2. Hydrochloric Acid

Hydrochloric acid (also known as muriatic acid) is a stronger acidic solvent that is also effective at dissolving old cement-based grout. It may be more suitable for thicker grout lines. However, it is also more hazardous to handle than sulfamic/phosphoric products.

If using hydrochloric acid:

• Use extreme caution and proper handling/ventilation.
• Pre-wet surfaces and avoid contact with skin/eyes.
• Test on a small area first.
• Limit dwell time to avoid damaging the tile itself.
• Thoroughly rinse surfaces.
• Neutralize afterwards with baking soda/water solution.

3. Urea-Based Grout Removers

For a more gentle grout removal option, look for products containing urea hydrochloride. This chemical will soften grout with less potential for tile damage versus harsher acid products. Urea removers may take longer to work but provide a safer option around sensitive tiles.

Manual Grout Removal Techniques

For wider grout joints or fully removing grout, these manual removal techniques can be used:

1. Grout Saw

A grout saw, rotary tool, or oscillating multi-tool outfitted with a rigid grout removal blade can be used to slice into and rake out grout. Apply light and steady pressure when slicing to avoid damaging edges of tiles. This method works well for larger grout joints.

2. Grout Rake

Manual hand tools called grout rakes feature a barbed metal edge that can scrape and pick out old grout. Grout rakes allow good control and precision for small grout lines.

3. Chisel & Hammer

For thick grout joints, a masonry chisel and hammer can knock out and pry up stubborn grout. Use a light touch and carve across the grout line carefully.

4. Steam Cleaner

A steam cleaner applies targeted, high-heat steam to soften and loosen epoxy-based grouts, allowing them to be scraped away. Take care not to damage tiles with the heat.

Steps for Re-Grouting After Removal

Once the old grout is successfully removed, follow these steps to refresh with new grout:

1. Sweep and wipe the tile to remove all debris and dust.
2. Apply grout sealer to the tile edges for protection.
3. Mix and apply new grout per manufacturer instructions.
4. Pack grout thoroughly into joints, holding float at a 45° angle.
5. Wipe diagonally across tiles to remove excess grout.
6. Allow proper cure time before cleaning and sealing.

Taking the time to correctly dissolve or remove failing grout and re-grout with new, waterproof grout will give your tiles new life and prevent future damage.

Tips for Preventing Grout Problems

To help prevent grout from needing replacement, keep these maintenance tips in mind:

• Seal grout annually to protect from staining and moisture.
• Caulk joints between tub/sink and tile walls to prevent water seeping under.
• Quickly wipe spills and clean grimy areas to limit staining.
• Install backerboard behind tiles for a smoother, more durable surface.
• Use a grout designed for your application and follow all manufacturer instructions.

FAQ About Dissolving and Removing Grout

Still have some questions? Here are answers to some frequently asked questions:

What is the easiest way to remove old grout?

For most tile jobs, using a chemical grout remover is the quickest and easiest method. Sulfamic or phosphoric acid-based removers are simple to apply to grout lines with minimal mess or damage risk.

Can I use muriatic acid to remove grout?

Yes, muriatic acid (hydrochloric acid) can dissolve cement-based grout. However, exercise extreme caution when handling muriatic acid and test a small area first, as it can also damage tile if left too long.

What removes epoxy grout?

Epoxy-based grouts require heat to soften and remove. Using a steam cleaner to target grout lines is the most effective method for epoxy grout. Grout saws can then remove loosened grout.

How long does it take to dissolve grout?

With a chemical grout remover, allow 5-10 minutes of dwell time to fully soften and dissolve the grout. More applications may be needed for thicker grout. Rinse thoroughly afterward.

Should new grout match old grout color?

Matching grout color is ideal if you have enough existing grout to sample or can find documentation on the original color. However, sometimes changing to a fresh, new color is preferred.

Conclusion

Removing and replacing old grout revitalizes the look of any tile surface. By dissolving or manually removing grout, you can create a clean foundation for fresh grout. Carefully follow product instructions for safe and effective results. And be sure to properly seal and maintain your new grout for a like-new appearance that lasts.