Is there a way to design/create a shower that is less prone to mold?

Question

I think I've had it with traditional tiled showers...I can't stand the site of mold in between tiles, on the tiles! on shower curtains, on shower doors, etc.

I think I'm pretty clean, but I always will see little bits of mold.

How can I build a shower that would minimize mold growth?

What materials would help? What about concrete? Can I treat the surface with anything?

What kind of enclusure structures would work? Can I treat the shower curtain with anything? What if the door were stainless?

Do I build a dehumidifying unit into the bathroom?

I'm looking for the ultimate bathroom/shower design.

I know that what ever the solution, cleaning will still be required...

Answer 1

General construction advice for 'general' showers:

In/on the walls:

• use RedGard as a vapor barrier over the cement board
• use paperless or blueboard sheetrock
• use mildew resistant pain
• adequately vent the room with a proper exhaust fan

In the shower construction itself:

• seal all caulk properly
• make sure standing water can't puddle

Now, all that said, I pretty much agree. Showers as they are today aren't really designed as well as they should be IMHO.

For inexpensive solutions, I'm actually a fan of the more modern pre-moulded systems. You can get systems that look quite nice for under $1500 that come in 3 or 4 full-wall sections with gasket seems. I know folks tend to consider them 'cheaper' than a true tiled shower, but I actually find them much more intriguing from an engineering standpoint. They just make more sense to me in a modern home.

For more quirky/unique solutions, I've seen:

• metal sheeting. Corrugated Galvanized sheets, for example. Copper as another.
• all glass
• sealed monolithic concrete (note that concrete is extremely porous so would have to be sealed with something like an epoxy coating)

And...most recently...we stayed at a new hotel a few weeks ago where the shower walls were made out of solid slabs of the same counter-top material as the vanity. It looked really nice actually, I'm guessing it was a Corian like product.

Answer 2

There is nothing unsanitary or unclean about a properly built and maintained tile shower enclosure, but maintenance and cleaning are key. Regular degreasing (with a detergent or soap), descaling (with a dilute acid) and sterilizing (with bleach or hydrogen peroxide) are key. Almost universally, any mold and mildew issues are solely the fault of the owners not cleaning the surfaces properly and often enough.

We build a dozen or more showers every year, and after many years of experience, the only ones that have problems are ones that aren't kept clean - and even those can usually be salvaged by a thorough cleaning and sanitizing prior to simple caulking and sealing.

Regardless of what anyone tries to convince you of, a well-built shower will need sealing annually, and caulking every 5 years. If you are going longer than this between either, you aren't cleaning aggressively enough or with the right chemicals, and if you are, and you don't reseal or recaulk when it's needed, you are creating the environment for more growth of mold and mildew and contributing to the breakdown of other components of the system the shower is built from.

@tester 101 is right - the least amount of maintenance will come from molded seamless plastics. But even they need regular intensive cleaning and resealing from time to time.

Answer 3

After doing some research, I found that there is:

• moisture resistant caulk
• paint that has antimcrobial additives

Adding a ventilation fan helps...with proper usage of course, i.e. running it for 5 minutes after showering.

So potentially using those elements in the shower/bathroom would help quite a bit.

Answer 4

Mould will grow in a moist environment, and showers are wet.

Any areas where water pools should be eliminated. Dehumidifiers (e.g. ventilation fans) are good, but they only help by removing and possibly circulating the air (i.e. exhausting existing air results in drier air from elsewhere in the house replacing it in the shower room, thus reducing humidity).

The main problem with moisture occurs due to condensation. This happens when water is present in the air, and it condenses due to a temperature decrease (warm air holds more water than cold air). Hence, no amount of exhaust ventilation will result in all water evaporating. In my shower room, for example, when it's cold, water condenses on the window and walls, then droplets merge and it dribbles down the wall collecting more water as it goes. It also condenses on the ceiling, which unfortunately happens to have an outside air vent above it in the attic.

One solution to this is to heat the air in the room (warm air absorbs more moisture, which can then be evacuated with an exhaust fan). Warming the shower room before having a shower will prevent some condensation, as the walls and ceiling of the room will be warmer, and thus less likely to cause the air in contact with it to cool and thus water to condense.

I'm planning on installing the Panasonic FV-11VHL2, but any means of heating (e.g. having the heater/HVAC on) and evacuating (exhaust fan) should do the trick.

A couple of other points (from experience):-

• Full panel glass shower doors don't have cavities inside which water can accumulate when caulk sealant deteriorates. Notice how for this shower door there is no track at the top or bottom. Such tracks are usually hollow and moisture can pool, attract mould and its spores, and potentially travel elsewhere via capillary action.
• Mix anti-mould mixture with paints before painting if they don't already contain it (something like Krud Kutter MC-2 Paint Mildewcide)
• Ensure that any caulks used have a Mildewcide in them. Research online the effectiveness of such caulks before buying. Over time, however, even the best caulks will have their effectiveness reduced. In this case, remove and recaulk.
• Seal tiles and grout periodically with a good sealant.
• Consider wiring the ceiling fan to a humidity-sensor timer, that allows timed operation (i.e. manually operated countdown time function), but also automatic activation if it senses the humidity level is too high.

Answer 5

A: Get a humidity sensing exhaust fan. Most have adjustable sensors. Some will operate for X minutes after the humidity has dropped below the set point.

Set it to something reasonable like 70% (Might have to be higher in coastal climates)

This will shorten the 'wet time' after each shower.

B: Teach users to wipe down the shower after use. This can be done with their towel, or with a squeegee. This reduces the amount of water the fan has to evaporate.

C: Mix up a spray bottle that is roughly half 8% cleaning vinegar and half winter windshield washer fluid. WWF is basically wood alcohol and water, about half and half. After diluting it with vinegar you are left with 25% alcohol. This should be a good anti-mold agent. The vinegar will remove hard water stains. Spray the shower once a week with this mix, and let it set.

The vinegar will attack grout. Clean the grout and reseal it before starting on theis regime.

If your water doesn't leave lime deposits, and you don't like to use alcohol (it is poisonous.) you can dilute bleach 10-20 to 1 and use it. For obvious reasons, don't spill on your clothes. Bleach may attack the chromework too. That's why I went to WWF for cleaning my pruners and grafting tools.

A third fungicide you can use is copper sulfate. Use about a tablespoon in a quart of water. I suspect it is also hard on chrome finish.