The biggest concern with a bathroom floor is water, in two forms: spills & splashes, and steam & humidity.

Relative Humidity in the Home

The air is able to hold onto a certain amount of moisture at any time. Warmer air can hold onto more than colder air, but at any particular moment, there is only a specific amount it can handle. If the air has 75% of that amount in it, the relative humidity is 75% - relative, again, because temperature (and air pressure) change the capacity. Once the air has more than 100% of the moisture it can handle, we get condensation on surfaces, and steam in the air. At least in a house we get steam.  Outside we get rain.

This can occasionally matter to floors more than pools of water do, because so many flooring materials absorb moisture. Even if their surfaces are covered with spill resistant finishes, the atmosphere and its humidity can flow around gaps, into little cracks, and under boards. However slow the process, natural materials like wood can gradually absorb moisture, especially in a room where high humidity is a regular occurrence. Also, it's likely that the floor is going to be cooler than the air in the room. If moisture filled air cools near the floor, it can release its moisture as floor condensation even if the room is otherwise unsteamy.

Good Options In Humidity

When considering humidity, there are some good options and some I don't recommend. At the top of the good list would be vinyl flooring. Installing your exact floor-shape cut out of a full sheet will be your best way to keep moisture from getting underneath, though if something tragic happens, a tear, or a break in the seal where floor meets wall, taking care of the resultant problem becomes extra difficult, because you basically have to rip this kind of floor out to dry anything underneath it.

Vinyl plank flooring is probably better. It installs as a floating floor or loose lay. The planks themselves are 100% waterproof, so they won't absorb the vapor. Also, if moisture traps underneath, vinyl would provide mold or mildew nothing to "eat", as would hardwood. The planks also won't be hurt if your bathtub overflows. In that circumstance, you could pull the planks up and dry them, then having quick and better access to your subfloor, you could fully dry that, then you would simply put your dried off floor onto your dried off subfloor. Inconvenient? Oh yeah, a flood always will be, but inconvenient and fixable is a cool breeze on a hot day next to the threat of having to rip up hardwood and replace it, on top of the inconveniences.

The latest development in plank flooring is called Wood Plastic Core, which could be described as an engineered vinyl, or as a 100% waterproof laminate floor, though the former is more accurate. In terms of material, it's closest to a vinyl plank, but it's also much thicker, and pretty rigid, so it functions like a laminate.

Here's a standard piece of vinyl planking atop a sample of Wood Plastic Core. The WPC has that yellow core topped by a layer of vinyl with the style of floor you like, and then a cork underlayment.

We carry COREtec™ and other brands, with more styles and options coming and going monthly. Both the thickness and the material with which it's made make it even warmer than vinyl plank. While not technically true, it really is the best answer we have to the requests we always get for a 100% waterproof laminate floor.

It can look very nice too. Vinyl doesn't have to look like a plasticky, patterned kitchen floor from the 1950's. Personally, I like those, but I lean retro; that's quirky me.   You shouldn't have to be stuck with them.

If your only concern is humidity, ceramic tile and stone would be great options.  The stones and tiles themselves would be impervious, but they can be cold on the feet, very slick when wet, and the grout must be maintained.  

Also just considering the steam, you could get away with either bamboo flooring or engineered hardwood. The very substance of bamboo is naturally resistant to moisture. Think about it – it can grow in ponds. Engineered hardwood flooring is specifically and well designed to be less responsive to the environment in general. Swelling, warping, cupping, rotting, all things which would threaten a solid hardwood floor, shouldn't happen with either the engineered hardwood or bamboo.

Bad Options In Humidity

The aforementioned solid hardwood is not your friend on a bathroom floor. It is very responsive to humidity and temperature changes, is a great food source for any mold attempting to grow underneath, and it won't have a moisture barrier beneath it to protect the subfloor because solid hardwood is nailed down. That also means that if there is a flooding catastrophe, to remove and replace it will be more than a little, weekend chore.

While increasingly better with these issues, at the moment, laminate flooring is not a great choice either (I say "for the moment" because laminate technology tends to leap forward in surprising ways.) 

While cork doesn't rot and is more resistant to moisture than wood, it is still not impervious to the humidity issues.

Carpet? In a bathroom? Just say no.

Good for Sitting Water

The splashing issue is less complex to sort out, as it's almost pass/fail. 

Carpet will soak, hold, and be ruined by spills. Mold loves a lot of carpeting material. 

Solid hardwood is almost as bad of an option in high spill areas, with laminate just behind it. 

Properly finished or sealed, engineered hardwood, bamboo and even cork can be made to work. With each, you can't let spills stay down for too long, or the water will seep through cracks between the planks. They're on the positive side of the list, but they aren't the best. 

Working upward, our best options remain the stone and ceramic tile options, then vinyl plank flooring and sheet vinyl at the top. With the rocky tiles we still have to worry about soaking the grout, but otherwise a spill is a non-issue. Vinyl plank is beaten here by sheets only because sheet vinyl has no cracks through which water may seep. Otherwise, both are great with spills.

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David has written and made videos about flooring products and installation since 2011 at Floors To Your Home (.com), where he is also the PPC Manager, a Researcher, a Website & Marketing Strategy Team member, Videographer, Social Strategist, Photographer and all around Resource Jito. In my spare time I shoot and edit video, put together a podcast, explore film history, and mix music (as in ‘play with Beatles multi-tracks’). Connect with  W. David Lichty

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