After my masons re-set my 15 year old flagstone walkways and patio, they advised me it should be sealed, and recommended a siloxane based sealant. Foundation Armor's product is highly recommended elsewhere, and I concur. Although seemingly expensive, the product goes a long way, and it comes with very good instructions. I used a simple pump sprayer, two applications as only a thin spray was needed to saturate and penetrate the stone. Cleans up easily with soap and warm water.

The matte clear finish is barely noticeable, just slightly darkening the stone and it penetrated well. Now just waiting to see how durable this product is, but seems well worth it in preserving my flagstone.

Overall a great, easy to use product.