Also useable is a tile sealer, sold in tile stores. Neither of these sealers have a shine, nor will they change the color of the tile. Thompson's Water Seal will also work. Q. I've had a sealer on my deck for 10 years. It still looks good.
Sealers last only a year or two before needing reapplication.
If the wood is pressure-treated, it doesn't need sealing, not when it's at least 10 years old.