Yes to bleach, no to 10%. Mould spores are a part of the natural environment. When conditions are right they can settle and germinate. When there is an amplified level compared to the natural environment then it is considered a concern. Or whether it is a toxigenic mould (like black mould).
Mould needs food and water to thrive. It can break down cellulose fibres in drywalls and woods, so getting it damp gives ideal growth conditions. Bleach does kill mould, but can leave a stain. If the conditions are still favourable, other spores will land and germinate.
Mould grows on surfaces and breaks them down, it only grows inward by attrition of the surface. Wherever mould will grow, bleach/water can also go and kill it.
Once the mould is killed the moisture component has to be dealt with. Replacing drywall would only be advisable if it is waterlogged as it will continue to allow spores to germinate until it is dried out. Humid/damp conditions can be dealt with via a dehumidifier.
Remediation companies are in the business to make profits. As you said, as a business you had to go an extra mile, they do too.
Most fungicides will use Quats, which acts in the same way as bleach. They generate chloride ions that disrupt the energy pump cycle in the mitochondria and thus kill the micro-organism, much as they do for bacteria as well. Quats is considered safer since the disinfection byproducts (THM’s) are not produced. 100 ppm bleach produces minimal THM’s but people always figure more is better…. it isn’t.
got a dollar tree close by?
you can get a uv-c source there for $1.
i got some and they are good enough to erase eproms.
safe & healthy germicidal light.
Thank you snake, i found them and will give it a try on some mildew.
How can they sell them for only $1 —online prices range from $6 to 30. When they came out “as seen on TV” they were $20 plus shipping. As of now even Bed,Bath & Behind has them for $10, Safe & Healthy UVC light
[edit] It uses a PIC10F20x micro to control switching the 6VDC thru a transformer to create AC for the fluorescent tube; snubber capacitor is rated 3kV. The 3.3V regulator is a Torex XC6206. i’ll try to get a reading of standby current later tonight.
Insert cells, inrush current: 3.3 mA pk
OFF with the door closed: 28.8 uA
OFF with door opened: 5.6 uA
ON with the lamp removed: 84.1 uA
ON with the lamp working: 340 mA
AAA cells probably won’t last long at 0.34A
Didn’t see any change in the mildew patch so don’t know if it is effective for this.
I’d be concerned about why there was mold (as others have noted).
The cause is likely behind the drywall. I’d don a respirator and pull the wall apart.
See what’s causing the problem. It might be larger than indicated from the outside.
There are places that will send you a kit to sample the mold then you send it off for analysis (for a fee).
Find out if it’s the toxic stuff or not. If it’s the toxic stuff, get it dealt with PDQ.
The mold spores are in the air. Wherever there is moisture and food (cellulose in wood/drywall) they will grow. The moisture can be from an external leak, plumbing leak, high humidity, etc. It can also be caused by a temperature differential from poor insulation that draws warmer moist indoor air onto colder surfaces (usually around doors and windows).
Mold speciation is not cheap and most moulds are not toxigenic. Black Mould (Stachybotrus chartarum/atra) is considered toxic in areas larger than one square meter, especially in rooms with long-term occupancy (living areas)
Deal with the mould, mechanical removal (scrubbing with soap/water and/or bleach/quats) and remediate the moisture issue by finding the source and dealing with it.