See my posts “The Basics of Mold Remediation – Part I of III – Containment of the Affected Area” as well as “The Basics of Mold Remediation – Part II of III – Gross Removal of Mold Growth and Impacted Materials” for background information important for understanding this part of the mold remediation process. At this point in our process, the mold impacted area has been isolated from all non-affected adjacent living spaces. This was accomplished by establishing containment of the area, which included the installation of HEPA Filtered Negative Air machines and installation of physical barriers which, in turn, would have created a negative pressure environment. Gross removal of all impacted non-structural materials would have occurred as well as the removal and cleaning of mold growth from all of the structural materials. The next step is to perform the final clean of the work area.
Part III of III – Final cleaning of the containment and affected areas.
Now that the nitty gritty portion of the removal has been accomplished, the work area has typically seen a fair share of debris. Not only does the removal of building materials create lots of dust and debris, but the disturbance and removal of the mold source itself typically creates very large quantities of microscopic mold spores. So, how do we make sure we account for all of those spores that we can’t even see with our naked eye? Well, the simple answer is by cleaning everything, and doing it very well. That means every crack, crevice, cavity, ceiling, wall, floor and the air itself must be cleaned.
The first step in the final cleaning is typically a complete HEPA vacuuming of the entire space. Every surface within the containment area will be HEPA vacuumed to gather any dust, debris, and yes, lots and lots of mold spores. The vacuums used are not the typical vacuum you can find at the hardware store, but specialized HEPA vacuums that prevent those microscopic spores that are being sucked up from being re-distributed throughout the space.
Once the area has been HEPA vacuumed, the remediation contractor will typically perform a wet wipe of the area at this time. They will use a cloth that is wetted with some sort of antimicrobial agent or cleaner, and every hard surface will be wiped down. The rags are kept wet not only to aid in the cleaning process, but to help in picking up mold spores and preventing them from becoming airborne.
At this point, some remediation contractors may choose to repeat the previous two steps, and HEPA vacuum the entire space as well as do another wet wipe to ensure that every surface has been accounted for. And after all, it’s better to be safe than to be sorry, or at least that’s what they say.
During all of the previous cleaning efforts, the HEPA filtered negative air machines have been running the entire time. As a result, airborne mold spores have been pulled out of the air and into the filtration device. As the cleaning has become more and more detailed, the airborne mold spore quantities should have been continually getting smaller. Unfortunately though, the quantities of airborne mold spores at this time will typically still be in excess of actual clearance standards. So, at this time the negative air machines are swapped out for HEPA filtered air scrubbers. Instead of air continually being drawn out of the space and as result unconditioned air being drawn into it, the air within the space will now be recycled through the HEPA filtered air scrubbers. As the air is continually pulled through the HEPA filters over and over again, it will become “cleaner” as more and more of those microscopic mold spores are trapped within the HEPA filter. This process is usually continued for a minimum of 24 hrs, and depending on the amount of contamination in the space may go on for multiple days.
At this point, the remediation project has come a long way. We have gone from a mold contaminated area, to what we hope is considered to be a “normal” living space. But, to truly verify whether the space has been returned to normal a Post Remediation Verification Inspection should be performed. This should be performed by an independent mold inspector who has no financial ties with the remediation contractor. They will perform a visual inspection of the space to ensure that all of the impacted materials have been removed and/or cleaned, test the moisture content of the building materials to ensure that everything has been adequately dried, and ensure that the area has been properly cleaned. If the visual inspection is adequate, then they will perform ambient air sampling of the work space. This will test for the presence, types and quantities of mold spores within the space and will be compared to an outdoor sample taken at the same place and time. If the sample is within clearance standards, the project will be considered successful, and the mold remediation project complete. All that is left at this point is reconstruction of the space to return it to a normal living space. After all that we have gone through, that should be a walk in the park…
by Brandon Apple, Mold Inspection Sciences
