Well I'm not a scientist, but I have read it in numerous places it's only the water in bleach that penetrates porous surfaces
http://www.sapper6.com/Mold_-_The_Bleach_Myth.html[/QUOTE]
There are many junk science sites on the web. Believe them if you wish. Here's what that webpage starts with:
Chlorine Bleach is NOT registered with the Environmental Protection Agency as a disinfectant to kill mold.
Here's the relevant quote from the EPA
http://www.epa.gov/mold/mold_remediation.html#Cleanup_Methods
Mold Remediation/Cleanup and Biocides
The purpose of mold remediation is to remove the mold to prevent human exposure and damage to building materials and furnishings. It is necessary to clean up mold contamination, not just to kill the mold. Dead mold is still allergenic, and some dead molds are potentially toxic. The use of a biocide, such as chlorine bleach, is not recommended as a routine practice during mold remediation, although there may be instances where professional judgment may indicate its use (for example, when immune-compromised individuals are present). In most cases, it is not possible or desirable to sterilize an area; a background level of mold spores will remain in the air (roughly equivalent to or lower than the level in outside air). These spores will not grow if the moisture problem in the building has been resolved.
If you choose to use disinfectants or biocides, always ventilate the area. Outdoor air may need to be brought in with fans. When using fans, take care not to distribute mold spores throughout an unaffected area. Biocides are toxic to humans, as well as to mold. You should also use appropriate PPE and read and follow label precautions.
The EPA does recognise that Bleach kills mold - but does not recommend it for routine cleanup because it may not cleanup all traces of mould (nothing else will either). Confusingly, it does seem to indicate that bleach may be the agent of choice when immune-compromised persons are involved.
Their recommendation is to remove, bag and destroy porous articles and to scrub hard surfaces, often after extensive HEPA or wet vacuuming to remove surface mould.
I worked in several Laboratories since I took my BSc. degree in Genetics. In the following 15 years working with a range of organisms including veterinary pathogens, viruses and bacteria that infected plants, I rarely used bleach except to sanitize glasshouse surfaces to remove algae. But I am not going to use Decon 90, fuming nitric acid, lysol or ethylene oxide around the home, am I?
Specifically I would recommend using neat thick bleach, which contains detergents as well as the active hypochlorite, applied directly to the surface with mould growing upon it, so that the mould spores are immediately wetted with full strength bleach, and then allowing it to dry onto the surface.
Bleach penetrates by two means - as liquid, with water as its major solvent, and as chlorine gas which reacts with water to form hydrochloric and hydrochlorous acids.
Bleach is a very rapid biocide - so rapid that the actual means of action has not been worked out, but it is clear that it destroys the majority of fungus and bacteria with a single application, and a second application a few days later increases the kill rate. It also hangs around with the chlorine smell being released over hours after application and drying.
Bleach will destroy haemoglobin in blood and DNA, making forensic analysis difficult or impossible if bleach is used to clean up after a crime. Proteins, glycoproteins and nucleic acids are all denatured and disrupted and broken down to smaller molecular components by the action of the active chlorine products.
Dilute hypochlorite has been used to debride wounds - to break down and dissolve dead tissue to leave a clean living tissue for healing, and our white cells produce hypochlorite to destroy microbes and foreign bodies ingested by these cells, so those with beliefs could say that The Superior Intellect designed it!
Why do I use bleach for condensation mould - it does not spread spores, it does soak in as far as it needs to, and it generally will not additionally damage decorated surfaces, beyond the damage that the damp and mould has already done, and also, it bleaches the greens and yellows and blacks and pinks of the mould. It will even work on wipeable wallpapers. If the mould returns, it is because the condensation and damp is back, and mould spores are present everywhere.
It is a different situation with wood rots - especially Dry rot, which can travel through plaster and brickwork. That does need to be cut out beyond the limits of infection, and treated with a chemical fungicide, before replacing wall surfaces and woodwork.
