I've had several mold remediation specialists come to my home each touting their preferred EPA approved mold killing agent including: Cal-brite, Fiberlock Shockwave, Microban BotaniClean. I've looked at the specs and can't tell the difference. Their prices very greatly. How do I know which one to use?
How to know which mold agent is best
mold
Related Solutions
A question - were there elevated spore levels in the rest of the house? It sounds like you disturbed something removing the old drywall. If that's the case you might be OK.
You need to identify the source. Once you've done that you can usually deal with the problem yourself.
The hard part is going to be identifying the source. Mould is usually caused by condensation on the walls, which in turn is caused by poor ventilation and insulation. So there's warm, damp air in the room which when it comes in contact with the cold wall forms condensation.
If there was no visible mould before removing the drywall, then you should be all right - but I'm not an expert so please don't quote me on that.
When you replace the drywall make sure you install adequate insulation and ventilation in the room and then perhaps test again for spores before decorating. If the levels are still high then you'll need to do more investigation.
Cover the vent
They sell magnetic vent covers at nearly all hardware stores. Buy one, and cover the vent when it's not being used. This will prevent moist air from entering the vent, though it may not stop water if it pools around the vent.
Install an exhaust fan
Install a properly sized exhaust fan in the bathroom. Let it run during showers, and for about 20-30 minutes after showers.
WARNING: Make sure you vent the exhaust properly.
Sizing an exhaust fan
Exhaust fans are sized using Cubic Feet Per Minute (CFM), so you'll have to first figure out how many cubic feet your bathroom is. To do this, measure the length, width, and height of the room.
- Length = 10 ft.
- Width = 8 ft.
- Height = 8 ft.
To find the cubic feet, simply multiply these numbers together.
10 ft. * 8 ft. * 8 ft. = 640 ft.3
Next we'll divide the cubic feet by 60, to figure out how many CFM is required to exchange the air one time in an hour.
640 ft.3 / 60 Minutes = 10.66 ft.3/Minute.
It's recommended that the air in a bathroom be exchanged 8 times per hour, so you'll have to multiply our CFM value by 8.
10.66 ft.3/Minute * 8 = 85.33 ft.3/Minute
So in this example, we'll need an exhaust fan with at least an 86 CFM rating.
Quick formula: (Length * Width * Height) / 7.5 = Required CFM rating.
Making sure the fan runs long enough
When installing an exhaust fan in a bathroom, it's a good idea to put the fan on a timer. This allows you to run the fan for the recommended 20-30 minutes after a shower, without having to worry about remembering to turn it off.
Warning: Make sure you get a timer that is rated for motor loads.
Best Answer
First, read through the EPA site on mold.
If you look carefully, you will not find an EPA recommended product.
Spores can be removed with detergent and water. Spores can be killed with bleach and other disinfectants (biocides), but the EPA says:
More importantly, is the source of moisture under control? Have all wet areas been exposed and dried out.
Once the interior framing is dried out to 10 to 12%, (consider buying a non-contact moisture meter and insist the framing be dried out before continuing), you can spray seal your framing with a primer to encapsulate any remaining spores and close the walls.