I have hard well water, no softener. Our new subway tiles have been up in the bathroom shower, all four walls and ceiling for a year and a half. We wipe down the walls after the last shower of the morning and DON'T USE BAR SOAP (we use liquid body wash). Those two adjustments were harder for my husband and grown sons who visit than me. They weren't the ones cleaning the bathroom! My grown daughter who visits has no problem with the rules at all :) Anyhow, my tiles still shine. If you look at them in certain light you can see...I don't know, evidence of when they need to be cleaned and it's not hard water residue because I can use Simple Green and a microfiber cloth to remove. Whereas on my kitchen granite where the water sits near the faucet I have to gently scrub with 000 steel wool (recommended by the granite people). With the daily care and no soap, I spend much less time cleaning the bathroom and the results are far more gratifying than the previous plastic tub surround.

The white cedar single stains described in this thread are mostly applied by dipping the shingles in stain at the factory which provides the best protection. Weatherwash is a brand of interior furniture stain that can be used on exterior wood with a protective coating of Weatherwash's Exterior Water Sealer. That seems like additional expense for less protection.

You have choices. 1) You can do the floor natural color and use all water based products to eliminate residual odors. 2) You can use a reliable oil based stain that is formulated to use with water based finishes and perhaps have some residual odor. 3) You can use water based stain and when the application is predictably unacceptable, you can choose selections 1 or 2 above. Other than water based aniline dye applied at full strength, I've not seen an acceptable water based wood floor stain. Which one were you looking at to recommend to your contractor?

Gaby what did you end up going with? Hi a have been through one contractor already because he would only put a clear on the floor as a sample why I ran around picking out stain colors! And now I have hired somebody else but he is an available to start till November. So I would love to know what you ended up doing to get the best possible outcome on your red Oak!