Not all mould that appears black or dark is of the deadly variety. There are four varieties of mould that are found in homes: one is deadly; the other three will only create an allergic or respiratory reaction in humans (depending on their tolerance / respiratory health, of course). It is quite easy to rule out the deadly variety and allay fears that fleeing one's home is necessary. Deadly mould (Stachybotrys) has received a good deal of media attention of late; it is important to note that it only grows where there is standing water, and there will typically only be standing water in the case of a flood that has not been contained or a leak (detected or undetected). The other three common indoor varieties of mould are: Cladosporium, Penicillium, and Aspergillus (some sources, i.e.: WHO) add Alternaria to this list, but in the thousand attics that we have tested and successfully treated, this has not presented as significant). Exposure to the above three moulds (Clad, Pen & Asp) which require only moisture to take hold, can be unsettling, but once the moisture imbalance has been corrected and the mould truly killed (and please be careful navigating this unregulated profession), the home can again become your safe haven.
In the business of mould remediation, the term "mould staining" gets used to explain away post-treatment residual discolouration of affected material(s). It is very important to note that residual discolouration is a sign that the treatment was not effective. The discolouration is, in fact, the mould spores and if you observe this "staining" over time, you will actually see it grow as repopulation of the affected material(s) occurs. In short, you should not be left with black discolouration after a mould treatment. This is an indication that the remediators do not have an effective treatment method, nor an adequate understanding of microbiology. HIP are routinely called in (almost 25% of the business we do) to re-treat the work of other remediators due to re-growth from ineffective treatment.
There is currently an architectural / design trend where reclaimed barn board and other varieties of previously-enjoyed outdoor wood features are brought inside to add interest to indoor spaces. Changing the intended purpose of a part of one's home (i.e., finishing one's attic as loft space) -- without making neccesary changes to keep the home breathing -- is also done with some frequency. Both practices have many environmental benefits and can infuse space with warmth and character. It is, however, very important that in both of the above scenarios the wood be tested and treated where necessary, and in the latter category that an attic be treated if there is black disclouration on the wood, the new insulation requirements be accounted for, and that any necessary adjustments to ventilation be made. HIP can provide consulation and / or service in both scenarios. The take away: bringing the outdoors in comes with considerations. The presence of black and grey colouring on wood is in most cases -- while beautiful -- mould.
Mould’s activity or inactivity is quite irrelevant. Take mould that is not deemed to be in a state of active propagation, add minor air flow (like that created by a fan or a person walking by), and you get visible clouds of spores released which often have the immediate effect of creating sneezing, stuffiness, watery-eyes and the like in those within sniffing distance (depending, of course, on the sensitivity of said folks). Inactive does not mean non-viable, so using it is a measure of safety or risk is not sound.
Fixing just the cause or just the mould = each represent only half the equation
There are mould spores everywhere -- indoors and outdoors -- and, we breath them in with no ill effect so long as they represent a small enough percentage of the particles in air. Where mould spores create an issue is where they are encouraged to set up shop in your home or business. They will only do this if they find an environment that is enticing enough, and that environment is one where there is high humidity, low air flow, and just enough yummy stuff around to sustain growth (water itself, wood, drywall, some types of insulation, et al). In order to ensure that mould is no longer present within a building envelope, the moisture / ventilation imbalance must be corrected + the mould and its spores must be killed. Doing one without the other will present a temporary / aesthetic fix only. HIP does both (you may choose to carry out our ventilation recommendations yourself) and it is for this reason that we can provide the unheard-of guarantee that we do.