Preventing mildew in shower?

[dave1949]

For the ventilation, you might be able to find a higher CFM capacity fan to replace the current one. Also, to be really effective, the fan needs to vent to the outdoors. I have seen some that do not, they just make a lot of noise and accomplish little in the way of removing steamy air. Can you verify the fan exhaust actually gets out of the house? Ventilation is the true cure for the problem, the Kilz will make it more resistant or tolerant of prolonged humidity.

 

[Pilot]

It does vent outside.

I think the problem with the vent is it's location--it seems to suck air in from the next room. The vent is between the next room and the shower. The only way I see to make the vent work is to relocate it directly above the shower or run a duct over to the shower ceiling, which would look ugly. Can't do it above the ceiling because of the direction the joists run--there's another floor above.

 

[dave1949]

It does vent outside.

I think the problem with the vent is it's location--it seems to suck air in from the next room. The vent is between the next room and the shower. The only way I see to make the vent work is to relocate it directly above the shower or run a duct over to the shower ceiling, which would look ugly. Can't do it above the ceiling because of the direction the joists run--there's another floor above.

If recessed can lights are an option (to replace the existing shower light if there is one), they do make light+fan combo units that are rated for use in a shower. I agree, the ideal would be to have the fan in, or very close to the shower.

 

[WayneB]

To be honest with you once its started its a pain to get rid of and not have it keep coming back, I do bathroom and kitchen remodels and I remember one time a home owner had this same problem on and on , would kill it out for a few month but it would come back, I looked outside the bathroom window and notice a large oak tree within 8 ft of the house with Moss growing on the side facing the window, I asked her does she ever open the window? her reply was yes all the time in the spring of the year, I said to her there's you're problem, The spores from that moss is getting into the bathroom, she said Wow! never thought of that before and that they been thinking of having the tree removed anyway, I was back there a year later after they had removed the tree, she said the mildew never has returned,

I think you should tear out the sheetrock that surrounds the tub inclosure mix spray of bleach/clorox and sray everthing down let it dry , and install either durarock or green board, then tile the above part of the shower/tub and use tile grout sealer you'll be good to go, I can see everyone now looking out their bathroom window,,
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I think this is a good approach to the problem. I went ahead and put tile in our shower area above the side walls and it has been over three years with mode free bathroom. I did the clean up and removed the mode before adding the tile. I agree with the green board too, although tyhat is a bit more work to get the project completed.

 

[dmccarty]

When I designed the house, I specified Panasonic vent fans for the bathroom.

Wow, I could not find the company but eventually I remembered their name. THAT is amazing! :laughing:

I bought some items from the company but today I would do some Internet comparison shopping. I don't know if their prices are good or bad. Service was just fine and the stuff we bought has worked as expected. More on that in a second....

Their bath vent fans are here:
EFI.org/store | Exhaust Only

Before I remembered the previous website, I found this calculator that shows how much CFM you need:
Panasonic Intermittent Ventilation Fan Selector

We used Panasonic vents in the bathroom rooms. That is not a typeo. :laughing: The master bath is not real big, not 5x7 either, but it has a small walkin closet, off a room that holds the sinks, bath tub, and shower, while the toilet is in its own little space off the main room. I don't remember the size of it all but I don't think the space is more than 12x12 or 12x10. It is larger than a standard bath of 5x7ish but it is not McMansion large.

The second bath room has three rooms. There is a large room that has the door INTO the bathroom and the sinks. Off the large room aka the sink room is two other rooms, one for the toilet and one for the bath. The bath and toilet rooms have doors. I designed the space so that the kids or visitors could be using the facilities with some privacy. The bath and toilet rooms are just big enough to hold the tub and toilet. The whole space would be maybe 12x12ish.

The baths have 10 foot ceilings so there is a decent amount of volume in the bath rooms.

I mention all of this to give you a size reference.

We put in these Panasonic fans. I sized the fans to handle the bathroom volume. When we were building, the inspector made us put in EXTRA vent fans in the toilet rooms. :confused2: Code is Code I suppose. The Panasonic fans were in the rooms where they were required to handle the moisture from the shower, baths, and sinks. Apparently the code requires vents in the toilet room.

This turned out to be a good thing. The Panasonic fans we installed are QUIET! Now we wanted quiet fans since we were sick of the noisy jet engine vent fans I have always had in bathrooms. The problem was that the vent fans are TOO quiet. :laughing::laughing::laughing: The fans are so quiet we have to turn on the noisy to code fans to remind us to turn off the Panasonics. :laughing::laughing::laughing:

We also installed small electric heater in the bathrooms which is really nice. We had timers installed so we could simply set the timer, the heat turns on and eventually, turn off. I wish we had the foresight to have done this with the vent fans. The wifey still leaves the things running.

We don't have a mold on the drywall. Everyone but me uses the kids bath, bathroom because it is small and heats up very well. Which means there is a huge amount of humidity in that space but there is no mold. The tile around the baths and showers is on cement board with Green board everywhere else in the bathroom.

If venting is NOT the problem, I would wonder if the shower walls are leaking and soaking the green board.

Later,
Dan

 

[hunterridgefarm]

Some good advice here.

Let me also add to the air circulation. When we built our house 5 years ago I put in a large walk-in shower in the master bath. It is tiled except for the ceiling and we have two vents in the bathroom. I had a problem with mildew on the ceiling and used a bleach solution to kill it and painted over with Kilz.

The biggest problem is lack of air circulation. I bought a medium size floor fan we use once we get out of the shower. I set it in front of the shower and turn it on high, it blows the moisture out, circulates the air and helps dry the shower. We do this every time we take a shower. Even if it only runs for 5-10 minutes. The last 3 years since doing this I have not seen a hint of mold or mildew.

 

[EddieWalker]

I'm a big fan of Zinsser primer. The oil based BIN is pure misery to work with because it sticks to everything, but it's just awesome. Most of the time I just use the 123 latex primer.

Household bleach is highly diluted. It works for laundry and wont damage your clothes. If you want to kill some mold, fungus and anything else on the wall, I use swimming pool SHOCK. it's a much higher concentration of bleach. It will make your eyes water and smell up the house. But it works!!!

Then I paint with a high quality exterior paint.

Eddie