# Bathroom moisture a real problem



## netsrik (Mar 30, 2008)

We are getting ready to put our house on the market and really want to solve this problem before we do w/out too much expense.  I just can't pass this problem onto the next person.  Our house is almost 10 years old.  It's 6 x 13 with a tub/shower unit.  The exhaust fan is 100 CFM but really doesn't seem to pull much.  You can put a piece of toilet paper to it and it'll hold but it doesn't really "suck" onto the fan like it's getting pulled up.  The tub/shower unit is on an outside wall and there's a cold air exchange that runs behind the wall behind the head of the tub.  I haven't had any problems wiping the mildew off the walls and ceiling, but the walls will literally look like moisture is running down them.  It does seem worse in the wintertime, but will notice it during warmer weather also, just not quite as bad.  If you take a shower and leave the door shut, the exhaust fan won't really clear the mirror.  I think the cold air exchange could possibly have something to do with it, (but I hope not a lot because there's not much we can do with that) and our bathroom is usually pretty cold because we don't really heat it, but the water temperature is pretty high.  Do you think just lowering our water temperature and possibly getting a low flow shower head would help.  Also, our walls are painted with a flat paint, and I thought maybe a different paint would help.

Any suggestions??


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## glennjanie (Mar 30, 2008)

Yes, use lower water temperature, the low-flow head and paint with mildew resistant latex enamel. Increase the fan to 300cfm and I think you'll have it knocked.
Glenn


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## netsrik (Mar 31, 2008)

thanks so much, Glenn.  I haven't seen a fan with 300 CFM but I'll be checking that out!!


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## sunroom wizard (Mar 31, 2008)

The 300cfm fan should be the answer to this. Do a search for them online they'll show up.


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## Hube (Apr 2, 2008)

netsrik; The 100 cfm fan you have should be able to do the job, IF installed properly. 
a 6 x13 bathroom with (i assume) a normal 8 ft ceiling=  624 cu ft. 
A 100 cfm fan should be able to move approx 600 cfm every 6 minutes, and over an hour should move approx 6000 cfm. which would be equivilent to approx 10 air changes in an hour.
8 to 10 air changes in an hour is what is normally recommended for a bathroom, so your present fan should be more than adequate.
Either you are not running the fan long enough or there is  restrictions in the exiting air flow. Are you sure the fan's "backdraft" is opening upon start-up? Also, is the exhaust piping free and clear of any debris,etc. and does it expel the exhausted air to the outside?
What size is this exhaust piping? 4" or larger? Hopefully it is not 3"


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## Quattro (Apr 2, 2008)

If you want to upgrade the exhaust fan, I highly recommend the Panasonic brand. They are relatively expensive (~$130) for a fan/light combo. However, they are extremely quiet, and very efficient at moving air. Upgrade the vent pipe while you're at it. 

Another thing to consider is a louvered door on the bathroom. Drawing air from the adjacent room (or hall) will help move the moist air out the vent. 

At the very least, get up in the attic and check to be sure your current vent is clear, as Hube suggested.


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## Hube (Apr 2, 2008)

Quote by Quattro;
" get up in the attic and check to be sure your current vent is clear, as Hube suggested".... 

A better plan would  be to get up on the ROOF and check the vent out.
Hopefully the vent terminates to the outside air.
Terminating a vent in an ATTIC space is an absolute "NO-NO"


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## Quattro (Apr 3, 2008)

Not much you can do on the roof. However, from the attic you can remove the vent pipe from the roof jack and the fan itself, and check it out.


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## Hube (Apr 5, 2008)

Quattro said:


> Not much you can do on the roof. However, from the attic you can remove the vent pipe from the roof jack and the fan itself, and check it out.


**********************************************************
Wrong!! from the ROOF you can remove the cap,etc and look into the pipe to see  if it is obstructed.
From the attic you will never be able to remove the outside part of the pipe from the roof jack, as the caulked weather skirt  will prevent this from happening. And even if you could you would never be able to recaulk around the weather skirt without going onto the roof.


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## Square Eye (Apr 5, 2008)

Hube,
Most of the exhaust fans in this area are vented with flexible lines. They're not hard to detach from the roof jack and a man can easily reach up into the roof jack and clear any blockages. If this fan is vented with flexible line, the line could be crushed, there could be a blockage at the fan housing, he may discover that it was never vented to the outside at all... There are several reasons to check the attic. Personally, I've seen a vent fan buried under 10 - 12" of blown-in insulation. I don't know if it was forgotten or just installed without but it happens.


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## inspectorD (Apr 5, 2008)

Checking the line for bees nests and crushing effects is fine. But if you are over 8 feet long on a 100cfm fan....you get minimal air exhaust. Also if there is a negative pressure on the house side, the fan may get no exhaust out because the house needs it for makeup air to breath.
Without trying to figure it out in person, go for the bigger fan, check the lines for blockage and don't run over 12 feet in a direct line, with no more than 2 - 90 degree turns. Problem solved.
Just my opinion of course.


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## Hube (Apr 5, 2008)

[QUOTES by Square Eye;
Most of the exhaust fans in this area are vented with flexible lines.

 They're not hard to detach from the roof jack and a man can easily reach up into the roof jack and clear any blockages. If this fan is vented with flexible line, the line could be crushed, there could be a blockage at the fan housing, he may discover that it was never vented to the outside at all... There are several reasons to check the attic. Personally, I've seen a vent fan buried under 10 - 12" of blown-in insulation. I don't know if it was forgotten or just installed without but it happens
Answer;*********************************************************
On the average home you do not even have to go up on the roof to see if it is vented to the outside.The termination point should be able to be seen from the ground.And if it is not installed to the outside, then you obviously have to up on the roof sooner or later to install it properly.
And fyi,any part of the fan or   pipe that is buried under any insulation is  good because it will eliminate any chance of condensation forming on the fan and pipe parts, thus leaking or dripping down into the ceiling below.


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## Square Eye (Apr 5, 2008)

*clarification*
I've seen an exhaust fan buried under insulation with no ducting at all.

This is a serious moisture problem. If you suspect that an exhaust fan is not ducted properly, by all means, find out what's going on now!


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## woodman (Apr 9, 2008)

netsrik said:


> thanks so much, Glenn.  I haven't seen a fan with 300 CFM but I'll be checking that out!!



Yes, a 300 CFM would do it if you do not mind the noise. You can go to 'Graingers.com' They sell mostly industrial quality products. Personally I created a unit from a simpler 'box' fan and encased it in wood that includes a 'window shutter' look to hide the ugly fan. You can buy this for 15bux or so from any wal-mart, lowes, etc. Hope this helps. Remember, when in doubt, become creative.


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## Quattro (Apr 10, 2008)

Hube said:


> **********************************************************
> Wrong!! from the ROOF you can remove the cap,etc and look into the pipe to see  if it is obstructed.
> From the attic you will never be able to remove the outside part of the pipe from the roof jack, as the caulked weather skirt  will prevent this from happening. And even if you could you would never be able to recaulk around the weather skirt without going onto the roof.



Not to prolong this "argument", but you're coming off a little strong, eh? 

In my particular house, there is absolutely NOTHING you could do from the roof to check the condition of the vent pipe from the fan to the roof. Nothing. Nada.

Not sure why this went on so long anyway...we don't even know if the OP's fan vents through the roof, or out a sidewall. 

I guess what I'm saying is...as Bill Clinton says...chill out!


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## Hube (Apr 11, 2008)

Quattro said:


> Not to prolong this "argument", but you're coming off a little strong, eh? IS THAT JUST YOUR OPINION?
> 
> In my particular house, there is absolutely NOTHING you could do from the roof to check the condition of the vent pipe from the fan to the roof. Nothing. Nada. MAYBE NOT IN 'YOUR' HOUSE, BUT THERE ARE MANY OTHERS ON THE BLOCK!!
> 
> ...


 WHO THE HECK IS BILL CLINTON????
WHY SHOULD I CHILL OUT,I'M NOT EVEN WARM YET


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## inspectorD (Apr 11, 2008)

Well now...  Now that all the hot air has been vented from the room... 
What have you done to remedy the issue? 
Does it seem to be working or do you need more advice?
Just here to help.


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