The varied natural colors and gently ruffled texture of flagstone bring warmth and visual interest to any living space. Flagstones have been in use since the 13th century, and were the flooring of choice for castles in England and Scotland. Flagstone is durable, simple to maintain and easy to clean. If your flagstone is looking a little too medieval, a bit of TLC with some household vinegar will have it looking new again.
Remove Dry Debris
Before cleaning your flagstone, remove all dust and debris. Wipe down walls with a soft whisk broom or lint-free cloth. Sweep patios and walkways with a sturdy broom, paying special attention to corners and especially to any damp, shady spots where leaves gather. The combination of dampness, shade and decomposing vegetation is a recipe for mold and algae, which can discolor your flagstone and make it slippery to walk on.
While bleach is the most effective household product for killing mold and algae, it can damage and discolor your flagstone. Vinegar contains natural antibacterial agents which are also effective against mold and algae, but won't harm your walls, patio or walkways. Pour a small amount of undiluted vinegar onto a stained area and go over it with a scrub brush. Let the vinegar soak in and sit for at least 30 minutes. Rinse the spot with clear water and let it dry. Repeat as needed to remove all traces of the stain.
Clean Your Flagstone
Mix together equal parts white vinegar and warm water. Make sure you do not use apple cider vinegar, balsamic vinegar or any other variety that is not clear, as they can stain your flagstones. Spray your flagstones with the vinegar and water solution, being careful not to soak any nearby vegetation. Vinegar isn't as toxic to plants as bleach is, but it can still damage them. Let the solution sit for at least 30 minutes and then rinse it with clear water.
Care and Maintenance
For long-term maintenance, sweep or dust your flagstones as needed. In the case of shaded patios or walkways, this should be done at least once per week to keep algae and mold from developing. Make sure that potted plants aren't leaking water onto your flagstones, and dry underneath the feet of metal patio furniture after it rains to help avoid rust stains. Wash your flagstone once a month with a vinegar and water solution, and consider power washing with a commercial cleaner once a year, making sure to keep the pressure low so that you don't damage the grout.