just got off the phone with a tenant down in Louisiana....said she's got mold on a few of her ceilings in the house

I know that she pretty much runs the A/C damn near 24/7, could this have anything to do with the mold???

I was thinking that it is too cold inside and with the heat/humidity outside it was causing problems.

The attic is insulated with I think R9 or R13 'glass

I plan on leaving CA on Friday evening for our lovely 36hr drive down South to do some other repairs...this was not on my list

A/C usually dehumidifies air.... what kind of vapor barrier do you have on the house? maybe that has something to do with it

...ummmmm???? I don't know

we never touched the outside walls or wood paneling.....

up in the attic, only the sheetrock and the insulation (pink rolled stuff)

You need 3 things for mold and mildew to grow. (1) Food- dirt etc, for the mold & mildew to grow on. (2) Moisture and (3) darkness. The A/C should be dehumidifing the house, so you may have other moisture issues

Mueller,
I gotta go with TimT on this one, not running the A/C in LA will cause mold.
The vapor barrier goes on the inside of the wall, on the backside of the drywall. Typically the backing on the insulation (the part that gets stapled to the studs) is the vapor barrier, but in humid climates where there is a large temp. difference inside and out, a second barrier is needed. This often consists of a sheet of plastic that goes floor to ceiling and is stapled to the studs just before the drywall is installed. All this keeps condensation out of the insulation and I guess it will help keep moister out of the house in general. Moister typically comes from the ground (no vapor barrier under the slab) or form inside the house (poorly vented showers, leaky pipes, leaky roof etc.).

Find the source of the moister and you will find the source of the mold.

Oh yeah, if she is running the A/C constantly (basically a necessity if you live in LA) and she is still not getting the moister out of the house, check the drip pan for the A/C. The drains on these often get clogged causing the pan to over flow or vent moister back into the house.

Clorox and Killz are the best things I have used to kill mold.

Good luck
-Pete

Yer gonna have to go up into the attic and look for mold or water leaks.

Don't ask me how I know... Darned attic roof vent (heater)


Former Florida boy Ken

You're probably dealing with mildew. Problem is everyone is so uptight about mold these days they panic everytime they see a little mildew. Yes, you will have to figure out the source of the moisture and try to stop it. If you don't find an actual leak of other source you may have to install a dehumidifier. I personally don't like vapor barriers in the walls. The walls are supposed to breath with climate changes and a barrier will trap condensation on one side or the other depending on the weather conditions.

I do know that the "Black Mold" deal has been real bad here in Texas. My inlaws and several others that I know have had their entire house gutted and remodeled to get rid of the stuff. Due to a loophole in the way the Texas homeowner's insurance form was written, the insurance companies took a soaking. Lot's of remediation/remodel shops popped up overnight. Insurance rates have sky-rocketed. Anyway I talked to a friend in New Orleans, he said the loophole in the Texas Insurance form, is not in LA's. He said in New Orleans the old houses are covered in it, they just gut and remodel. Doesn't get rid of it, just hides it for few years. Anyway if you are in Beaumont, fell free to contact me for dinner or whatever. PM for my no#.

Moisture barriers are to keep moisture out of the insulation. Wet insulation = loss of R value = higher heating/cooling costs.

In cold climates, the warm moist inside air cools and condenses against the cold dryer outside air.

The reverse happens in warm climates. Warm moist outside air condenses against the colder inside aircondishioned air.

Every break in the vapour barrier lets moisture into the insulation (electrical wall pulgs, light fixtures, even the staples used to hold it to the studs cause leaks) Wet insulation causes mold and paint to flake off outside walls.

Mike,

is this a attic mounted AC/heating unit? If so, (as mentioned above) the drain could be blocked and water could be getting into the insulation and causing the mold to work thru the drywall, showing inside the house.

Now the bad part, if the drain is the cause it's a simple matter to unplug it and reroute it so it can't happen again.

The drywall might have to be replaced if it is mushy. Don't poke at it till you find out the cause. It can be let dry and painted with alumumum paint to stop the mold from showing thru the paint again. Paint stores sell expensive "stain stopper" paint, but it's basicly just alumumum paint. Coat with the alu paint and then repaint with your regular house paint.

The insulation will have to be removed in the attic where it's wet. It can be taken out and dryed (over time) but it's faster to just R & R it. Increasing the R value in the attic lesssens the interchange of the cold/heat moisture

Be careful in the attic, one slip and you will be patching ceilings (and bones if you fall thru). Get some 1' X 6" X 6' boards to walk on while up there. Place them across the joists.

You might want to put some extra vents in the attic while up there (gable end or roof type) in case it's trapped moisture that is causing the problem.

Drink plenty of water while up in the attic, you will need it this time of year.

Moisture barriers keep liquid water out of the wall, totally necessary.
Vapor barriers keep air from taveling through the wall, not necessary in all areas. If the humidity is so high that condensation is a constant problem then it may be necessary but has to be installed on both the interior and exterior, otherwise you are trapping condensation on one side or the other depending on weather changes. I prefer a wall that breathes, and deal with the humidity in other ways, but I've never lived in Louisianna.

Running the A/C all of the time means that the windows and doors are shut all of the time. Everytime she takes a shower, washes dishes etc. that puts moisture into the air in the home. Chances are that the interior humidity in the house is even higher than outside. Vapour barriers work both ways and unless you have a complete air exchange system built into the HVAC you will need to have a window open to air out the house from time to time.

We can get mildew issues up here in new "airtight" homes be it winter or summer. I run a dehumidifier all of the time in the basement and try to open all of the windows to air out the house as often as possible.

Good luck.

i hope this won't be too much of a nightmare. the attic has to have some venting as well. make sure the sofit vent holes aren't covered by the insulation. if they are you'll get no convection air movement. if you have to repaint use KILS for a primer and add some mildew retardent. make sure the bath fan is properly vented, and the kithen fan (if there is one) too. tell the tenent to run them during the day periodicly, even when not showering or not cooking. ac, i hate it. luckily, in werstern wa, all the windows open and a few fans do the trick on all but the hottest days.

kevin

yeah, both of those hottest days. you are right, Kevin, absolutely right. one of the reasons it is a nice place to live.

After doing some mold cleaning in our home, I found out quite a bit about it.

First of all, mold, mildew it's all basically the same thing, mold.

You have to kill it and clean it. Kill it with bleach, and clean it with detergent. We used a garden sprayer with a bleach solution to kill it, and then sprayed it with a detergent solution.

You need to have a respirator cartridge for the bleach vapors though.

Good luck!

PK

cheap insurance against mold ...

update....found out most of the areas affected are near the vents for the heater and a/c, seems that moisture is coming out of the vents????

central heater-a/c unit, built-into the main structure of the house, not in the attic....

Yup, I'm betting on a clogged drain or some other source of water on the floor around the furnace. If the evaporator coil can't get rid of the condensation (the drain), then the fan will pick up the condensation and blow it back into the house (kind of like the "swamp coolers" they use in dry climates). The fact that she hasn't complained about this in the past is another clue that points at the drain. I live in Missouri and it's humid as a MoFo. My attic has "0" vapor barrier and I have never had any problem with mold/mildew. Another thing to check is the under side of the evaporator coil. If she doesn't change the filter on a regular basis (show me one renter that does), dirt will collect on the bottom (or upstream side depending which way it's mounted [upflow/downflow/horizontal]) of the coil and prevent the condensation from draining off the coil properly. Use a snow brush, or some other narrow stiff bristle brush to get the big stuff, then spray the hell out of it with 409 cleaner and let it run.

This is unrelated to your mildew problem, but you'll also want to clean the crap out of the condenser coil (outside unit) by killing the power (duh) , and using a nozzle on a hose squirt the water through the coil in the opposite direction of the normal airflow. You may have to move the fan out of the way to do this, but you'll be amazed how much stuff comes out of it.

I owned/operated a HVAC company for 15 years and still have all my accounts at the wholesalers if anyone on this board is needing HVAC parts cheap I can hook you up(normally a 200% to 300% markup on parts if a local company does the work for you).


Kevin