Sweatin' like a poodle at Michael Vick's place.

[mgbinspect]

OK, here's one for the brain-trust involving my own little pad.

I bought this place as a rental, and when times got tough, I unloaded my bigger home and moved into this little 1040 SF pad.

The old folks that lived here were "old school". They painted the bathrooms with gloss or semi-gloss paint. Every time you shower, in spite of a brand new vent fan that seems to push air pretty good, every surface in that bathroom gets dripping wet with condensation and in about three weeks mildew begins to pop up on the surface.

I'm thinking I'll need to just yank the drywall and start over with flat paint so the drywall can take on and slowly give up the moisture, which is why it hasn't gotten done... Who has time for that? It's the old, "Cobbler's children have no shoes" deal.

I know there may be some that disagree with flat paint in a bathroom, but my last house had flat paint in three bathrooms and the nine of us (five females, and you know they like scalding showers) never cause any condensation on the walls. We never had a millisecond of trouble with mildew, etc.

So, any ideas short of a total gut of the bathroom?

[David Meiland]

First thing to do might be to measure the fan flow with the door closed. Changing the wall paint so that the drywall can absorb and give off moisture seems highly improbable. Is the showerhead one of the watersavers that atomizes the water into a fine mist? If so that doesn't help.

Anyway, get the ventilation right, including a timer that keeps it running after you leave the room.

[mgbinspect]

First thing to do might be to measure the fan flow with the door closed. Changing the wall paint so that the drywall can absorb and give off moisture seems highly improbable. Is the showerhead one of the watersavers that atomizes the water into a fine mist? If so that doesn't help.

Anyway, get the ventilation right, including a timer that keeps it running after you leave the room.

The fan is brand new. My son-in-law replaced the motor and fan. It seems to roar and is heard outside, but you may have a point. I should check the real air flow.

As a matter of fact, it is the very shower head you mention. That's a good suggestion.

Thanks!

[Jim Morrison]

I don't think that paint is your problem. I haven't looked it up in a long time, but you can google yourself up a bathroom fan sizing chart. Just measure the cubic feet of your bathroom and buy the appropriately sized fan. Until then, I'd leave the bathroom door open when I showered, if possible and check to make sure that your vent hose is properly connected and unblocked.

[mgbinspect]

I don't think that paint is your problem. I haven't looked it up in a long time, but you can goggle yourself up a bathroom fan sizing chart. Just measure the cubic feet of your bathroom and buy the appropriately sized fan. Until then, I'd leave the bathroom door open when I showered, if possible and check to make sure that your vent hose is properly connected and unblocked.

My thinking was, in my delusional mind anyway, that possibly drywall acts a bit like a sponge, harmlessly absorbing moisture that would typically condensate on a glossy finish and then slowly giving it back through evaporation. Our bathrooms in our last home never experienced any noticeable condensation on flat painted drywall surfaces.

The bathroom in question is pretty small and condensation happens pretty darn quickly.

The fan needs to be checked out for sure. I'll do that. The cracked door is a good idea as well.

And the shower head is definitely one of those atomizing units. That was a great point. I'm sure changing that out will help, although I like and will miss it.

[David Meiland]

Lots of bath fans make lots of noise. The trick is to test it with the door closed. If the door is not undercut enough that can restrict fan flow. If the installer used 50 feet of pipe and 8 elbows to get out, that can restrict fan flow. The pipe could be blocked, etc.

[Tom Raymond]

Mike Holmes does the 'tissue test'. Hold a tissue up to the fan to see if it has enough oomph to move the tissue. That will tell you a lot[]

[John Kogel]

I'd leave the bathroom door open when I showered, if possible and check to make sure that your vent hose is properly connected and unblocked.

That's a funny one. []

[Jim Katen]

I recall Jeff May doing some research on bathroom fans. He concluded that they're all too small to remove moisture quickly enough to be effective at preventing condensation. He had to use a 20" box fan.

- Jim Katen, Oregon

[mgbinspect]

Yeah, I'll keep ya'll posted. I think the shower head is the biggest single culprit. It IS one of those very low flow super fine spray shower heads, and it definitely kicks up a lot of moisture. I hadn't really given it a thought, but I plan to change it out this weekend.

The guts of the fan are only about 45 days old. I'll check the pipe and destination.

[hausdok]

I recall Jeff May doing some research on bathroom fans. He concluded that they're all too small to remove moisture quickly enough to be effective at preventing condensation. He had to use a 20" box fan.

- Jim Katen, Oregon

I have no doubt about that.

As a teenager, I learned that the ceiling fan in the upstairs bath wasn't good enough to remove all of the moisture that would accumulate in the bath during a shower. I learned to use a large towel as an exhaust fan; I would stand off to one side and swing that towel like a fan really fast on a vertical axis between the floor and ceiling and it would pull in fresh air under the door (or through the window in warmer weather) and push more air out of the ceiling fan and dry the bath out really fast.

40+ years later, I still find myself assisting the ceiling fan with the same technique. When my wife walks into the bath when I'm done with it, it's dry in there. When I walk into the bath when she'd done with it, there's condensation all over everything and I have to grab the towel and do the fan thing.

Panasonic makes some really powerful and quiet ceiling fans. You have to mount them to the attic framing and run a duct down to a collector box at the ceiling of the bath, but they're kind of awsome.

ONE TEAM - ONE FIGHT!!!

Mike

[mgbinspect]

So, just curious, does anyone think that flat painted drywall offers any assistance at all or is my theory just plain flawed? [:-wiltel]

[hausdok]

Flawed

OT - OF!!!

M.

[Tom Raymond]

Uhm, Mike is in Virginia. This time of year a jet turbine wouldn't remove the moisture from the bathroom before it condenses.

I was in Lynchburg in June. At 90+ degrees the RH was so high, even in my climate controlled hotel room, that I started sweating as soon as I shut the shower off. Possibly before the last drop left the showerhead.

[mgbinspect]

Uhm, Mike is in Virginia. This time of year a jet turbine wouldn't remove the moisture from the bathroom before it condenses.

I was in Lynchburg in June. At 90+ degrees the RH was so high, even in my climate controlled hotel room, that I started sweating as soon as I shut the shower off. Possibly before the last drop left the showerhead.

It is indeed a curious phenomenon. Regarding humidity, Floriday has nothing on Central Virginia. They're both about as bad as it gets.

[Marc]

So, just curious, does anyone think that flat painted drywall offers any assistance at all or is my theory just plain flawed? [:-wiltel]

No significant assistance offered. Drywalled ceilings would sag between the joists before long if they did indeed absorb that much humidity.

I sometimes switch the central AC fan from 'auto' to 'on' before taking a shower. It pulls air from elsewhere in the house to lower the negative pressure developed by the bath exhaust fan when the bath door is closed. This allows a better performance of the exhaust fan.

Marc

[David Meiland]

The wall surface is cold, so vapor turns to liquid when it comes in contact, and I bet a very large percentage of the vapor turns to liquid with a tiny percentage diffusing into and thru the drywall. Changing the paint sheen will not change this appreciably.

We have two bathrooms, they are both about 60 square feet and the same cubic volume. The one I built is served by a 120CFM Panasonic inline fan that moves about 95 CFM with the door and window closed, as measured by an Energy Conservatory device suggested to me by someone here at TIJ. The showerhead is low flow but does not produce a mist, it produces droplets. The inlet to the fan is in the ceiling directly above the shower. You can't steam that room up much at all. The other bathroom has an older 50CFM fan that moves about 35 CFM, and you can make it foggy in there. In building new homes and remodeling baths I have been able to get pretty much every bathroom to vent well. The keys are to oversize the fan, run a clean duct, and undercut the door.

[mgbinspect]

So, just curious, does anyone think that flat painted drywall offers any assistance at all or is my theory just plain flawed? [:-wiltel]

Drywalled ceilings would sag between the joists before long if they did indeed absorb that much humidity.

Marc

Now Les may say differently, since he also has done disaster restoration, but I found that only two conditions tended to cause drywall to actually sag downward: 1. ponding water over it, as would occur when a tub or shower drain leaks regularly or 2. through the weight of wet insulation on the drywall.

It always seemed that, in general, drywall could endure a pretty good soaking and dry out to be just fine. Of course, I was doing disaster restoration work before everyone began to freak out about mold. Back then, if the drywall didn't change shape, the industry standard in our area was to let it dry, stain-seal it, paint it and go on with life.

[Jim Katen]

. . . I found that only two conditions tended to cause drywall to actually sag downward: 1. ponding water over it, as would occur when a tub or shower drain leaks regularly or 2. through the weight of wet insulation on the drywall.

It always seemed that, in general, drywall could endure a pretty good soaking and dry out to be just fine. . . .

Out here, people sometimes put drywall on the walls & ceilings of unheated outbuildings. That drywall sags, buckles, generally turns to mush.

As for the flat paint vs glossy paint issue, I don't know the answer. I think that something is going on though. If you have a shiny wall next to a flat wall, the shiny wall will condense up faster than the flat one. Somehow I don't think it's related to absorbtion though. I'll have to ponder that one for a while.

- Jim Katen, Oregon

[mgbinspect]

. . . I found that only two conditions tended to cause drywall to actually sag downward: 1. ponding water over it, as would occur when a tub or shower drain leaks regularly or 2. through the weight of wet insulation on the drywall.

It always seemed that, in general, drywall could endure a pretty good soaking and dry out to be just fine. . . .

Out here, people sometimes put drywall on the walls & ceilings of unheated outbuildings. That drywall sags, buckles, generally turns to mush.

As for the flat paint vs glossy paint issue, I don't know the answer. I think that something is going on though. If you have a shiny wall next to a flat wall, the shiny wall will condense up faster than the flat one. Somehow I don't think it's related to absorption though. I'll have to ponder that one for a while.

- Jim Katen, Oregon

Yes, now that you mention it, drywall out in sheds and outbuildings does indeed tend to do that - front porch ceilings too. Unconditioned space is not a friend to drywall. That's for sure. I was more referring to sudden and accidental one time or short term stuff. Repeated soakings does destroy drywall. It gets pretty gross.

My interest is peaked. It would be tempting to put a piece of drywall in the bathroom in question and compare the moisture readings between the glossy painted and flat drywall surfaces after one of the condensation producing showers. Much of the house still has the same nasty semi-gloss paint, so we'd even have a control. Let's devise a testing procedure and I'll do it. [:-graduat

[Bain]

Just an opinion, but there may be some over-analyzing happening with this one. I assume that if the house is 1K square feet, then the bathroom is relatively small. If you take really hot showers, stay in there for ten or fifteen minutes, and the bathroom is approximately 8 x 8 x 8 (ceiling), well, you're gonna wind up with condensation on the walls. Rather than all the other stuff, you may want to try lowering the water temperature, especially with the atomizer shower-head.

As for the paint, I'm clueless. But generally, any kind of paint has low porosity and permeability, so I don't understand how it could be the culprit.

[mgbinspect]

Just an opinion, but there may be some over-analyzing happening with this one. I assume that if the house is 1K square feet, then the bathroom is relatively small. If you take really hot showers, stay in there for ten or fifteen minutes, and the bathroom is approximately 8 x 8 x 8 (ceiling), well, you're gonna wind up with condensation on the walls. Rather than all the other stuff, you may want to try lowering the water temperature, especially with the atomizer shower-head.

As for the paint, I'm clueless. But generally, any kind of paint has low porosity and permeability, so I don't understand how it could be the culprit.

My guess is, based upon all the things suggested, that as soon as I convert to a low flow steady stream shower head, conditions will be markedly better after a shower.

I'm just kinda curious about the flat paint because of the fact that our previous home never had any such problems with five women taking the typical scalding showers.

I suppose, when I think about it, your probably right, Bain. It makes sense that even flat paint surfaces would be pretty moisture resistant.

But I might still have fun with the experiment and report back to this thread.

[Bain]

Just an opinion, but there may be some over-analyzing happening with this one. I assume that if the house is 1K square feet, then the bathroom is relatively small. If you take really hot showers, stay in there for ten or fifteen minutes, and the bathroom is approximately 8 x 8 x 8 (ceiling), well, you're gonna wind up with condensation on the walls. Rather than all the other stuff, you may want to try lowering the water temperature, especially with the atomizer shower-head.

As for the paint, I'm clueless. But generally, any kind of paint has low porosity and permeability, so I don't understand how it could be the culprit.

My guess is, based upon all the things suggested, that as soon as I convert to a low flow steady stream shower head, conditions will be markedly better after a shower.

I'm just kinda curious about the flat paint because of the fact that our previous home never had any such problems with five women taking the typical scalding showers.

I suppose, when I think about it, your probably right, Bain. It makes sense that even flat paint surfaces would be pretty moisture resistant.

But I might still have fun with the experiment and report back to this thread.

Just so we're clear, I wasn't belittling anything you or anyone else said. It's just that when my gal takes a shower, she closes the door and leaves the fan off 'cause she doesn't want to be cold when she finishes. When I walk in the room, it's like a Turkish steam bath. I have my fan wired into a timer switch, and have (mostly) trained her to let the fan run for twenty minutes once she's finished.

The timer is actually pretty cool, and may help you cut down on the mildew. You can hit the switch and the fan will automatically shut down when you tell it to.

[kurt]

I'm a big fan (!) of timer switches and either Panasonic or FanTech inline fans up in the attic.

We've taken to running the exhaust duct branches to the shower ceiling & the water closet; exhaust fresh air through a shower, especially a steam shower, makes it nice.

I like the timers that have the incremental buttons, for 5, 10, 15 minutes, etc.

[mgbinspect]

Just so we're clear, I wasn't belittling anything you or anyone else said.

The thought never crossed my mind, bro. I don't take offense easily. We're cool. [:-thumbu]