hi there, TImber stands up surprisingly well to water. You do have to be mindful that it isnt as durable as tiles and not splash water everywhere all the time but in reality most people dont. You need to seal the timber with a durable decking sealer. in this case the timber is 100 year old Australian hardwood as well so it will not rot in a hurry. You need to choose a timber species that is water resistant. Im not sure where you are but most countries have a few species that are. If you do that, then even if the surface deteriorates you can sand back and refinish the timber in 5 years. you cant do that with tiles!