Sealing Sandstone—Here’s How It Works

Sealing Sandstone Properly—Cleaning

Rain and dirt leave unsightly stains on patios and stairs. Before you can begin sealing the stone, these impurities must be removed. Sealing closes the pores of the stone, preventing further dirt from penetrating the stone and halting further weathering processes. 

• First, the stone must be cleaned. Under no circumstances should you use a pressure washer, as the high pressure forces dirt deeper into the stone and also damages the surface.
• Remove loose dirt. This can be done, for example, with a soft-bristled broom. It’s important to use it to remove loose debris such as dust, small stones, or leaves. 
• Now you can proceed by removing the more stubborn dirt. Use a brush for this. To avoid inhaling dust during this process, you can dampen the brush by briefly dipping it in water. This ensures that the dust stays on the ground and doesn’t get kicked up into the air.
• If there’s any stubborn dirt left that can’t be removed by brushing, try using a stone cleaner. 
• Moss and algae can be removed with an algae and green film remover. 

Sandstone – Sealing

Sealing the sandstone protects it from future soiling. It is much easier to keep a sealed surface clean and maintain it. A distinction is made between impregnation and sealing. These are similar, though impregnation is diffusion-open, meaning it preserves the stone’s breathability. However, the principle of operation remains the same in both cases. 

• If the surface has become wet during cleaning, wait until the stone has completely dried. Otherwise, the moisture would be permanently trapped in the stone, which can quickly lead to damage.
• Apply the waterproofing agent to the sandstone.
• The liquid can be applied to the sandstone with a brush, spray, or roller. 
• Now you simply need to wait for the liquid to dry thoroughly. Depending on the manufacturer’s instructions, you may also apply another coat. 
• There is no set timeframe for when the procedure must be repeated. As soon as you notice that the sealant’s effectiveness is wearing off, you should repeat the procedure.