Mold remediation contractors in Florida are generally conscientious, trying hard to bring each project to a condition where it will pass “clearance testing” (the Post-Remediation Verification inspection) on the first try. Some mold remediation guidance can be useful so that cleaning attempts are successful. If unsuccessful, this will certainly cost the mold remediation contractor additional cleaning time and therefore money, and it may damage their reputation with their client and/or insurance personnel. Depending on their contract, the contractor may be responsible for some or all of the cost of follow-up testing.
Basic Mold Remediation Guidance for Contractors
Below is some mold remediation guidance to help Florida contractors become more effective. They address what in our experience are the most common reasons a project does not pass the Post Remediation Verification or clearance testing. They are listed in no particular order.
Physically remove all mold growth
This seems obvious, but it is surprising how often competent professionals miss areas of visible mold growth. Careful inspection is the key.
Many Florida buildings have block exterior walls, with wood furring strips for attachment of drywall. When drywall is removed from these walls as part of mold remediation, Indoor Environmental Technologies (IET) highly recommends also removing all exposed furring strips, perhaps by cutting them off at the edge of the remaining drywall with a wood chisel. The alternative is to aggressively clean (resurface) the furring strips, which is time-consuming and therefore expensive, and increases the chance of inadequate removal of mold growth. And, of course, it is not possible to clean the reverse side of the furring strip where it is against the block. Furring strips are very inexpensive and we can pretty much guarantee it is considerably cheaper to remove and replace them than to attempt to clean them. These considerations apply especially to the horizontal bottom strip, which is usually a 1×4.
Note: Chromated copper arsenate is (CCA) often used to pressure-treat wood and make it rot-resistant. CCA-treated wood is sometimes used for furring strips, especially the horizontal bottom strip. This type of wood should never be aggressively cleaned by sanding, blasting, or brushing. It should be removed and replaced to prevent aerosolization of toxic arsenic compounds.
Cleaning to a “dust-free environment” level of cleanliness
There are two efficient ways to determine when this level has been reached.
1. White paper towels folded and wiped across surfaces in a “white glove” type of test.
2. A flashlight held parallel to and just above a surface. Dust particles are highlighted and easily seen. LED flashlights seem to work better for this purpose.
When carpet is removed and replaced, tackless strip is exposed. We recommend removing and replacing any tackless where discoloration indicates even brief contact with water. Our surface samples over the years have shown these strips often support mold growth even where it is not visible to the naked eye, and for obvious reasons, thorough aggressive cleaning of tackless strip is hazardous and often ineffective.
Carpeting can be a tricky item. In homes with elevated mold spore concentrations, the carpeting will act like a microbial reservoir. In that instance, HEPA-vacuum all carpeting, and then proceed with steam-cleaning. It is recommended that a truck-mounted system with hot-water extraction (approximately 160 F at carpet) capabilities be used. Ensure rapid drying as a normal maintenance procedure. Carpeting must be dry within 8 hours (12 hours maximum) to avoid possible microbial amplification. In some cases, it may be prudent to require two complete cleaning cycles to ensure a more thorough removal of mold spores.
However, in significantly contaminated environments, steam cleaning is often insufficient for removing elevated mold spore concentrations. In that event, replacement of the carpeting is needed. Carpet removal and replacement is often a wiser choice than attempting to clean it. Carpet acts as a “sink” for soils and dust, including mold contaminants, and it is virtually impossible to restore carpeting to a “like new” condition once microbial growth concentrations have reach significant levels.
In homes with significant contamination, IET cannot guarantee that cleaning attempts will be successful. So, if carpeting subjected to significant contamination remains in place and cleaning is performed, testing of the contaminated carpeting must be performed prior to allowing the homeowners to re-occupy the room. If carpeting is removed, passing the post remediation clearance test often becomes considerably easier.
Tops of doors and door/window frames
These are the areas most commonly missed during detailed cleaning.
A pocket door must normally be disassembled if the interior is to be properly cleaned. Even after disassembly, access is often challenging.
Often a decision is made about whether mold remediation of side A of a wall is needed by opening the more accessible or less intrusive side B of the same wall to examine the reverse side of the drywall on side A. While a perfectly valid inspection method, IET has found that significant mold growth is often found behind the baseboard of side A even when the reverse side of the same piece of drywall shows no visible mold growth or water staining. This is because the reverse side of drywall, exposed to the air of the cavity, is often able to dry more rapidly than the face side where it is covered by the baseboard. To avoid leaving mold growth behind, always check behind the baseboard in any areas that could have possibly gotten wet.
One of the most common reasons for significant mold growth is the classic “water damage” event caused by a broken pipe or other water release or intrusion. A competent restoration professional, if brought in quickly enough, can often dry the building before significant mold growth occurs, particularly if the Class of water damage is no higher than 2.
In most residences, the primary “Achilles heel” of a building with this type of damage is the built-in cabinetry in kitchen, bathrooms and elsewhere. The cabinets themselves and particularly the drywall behind them are very challenging to dry quickly enough to prevent mold growth. The best way to dry these surfaces in most cases is to remove the cabinets for direct access to the walls. Unfortunately, most recently-built homes, particularly the higher-end ones, have granite or other expensive types of countertops. These can seldom be detached and moved without breaking, greatly increasing the cost and disruption of the drying process. Homeowners and insurance personnel are therefore often unwilling to authorize cabinet removal.
As a result, this is the most common place for significant mold growth to develop after a major water damage that was professionally dried. Mold remediators need to be aware that exploratory demolition is often required to determine whether walls and other materials in these areas have undergone mold growth.
Seal AFDs prior to shutting them down
Air filtration devices (AFDs, negative air machines) should always have their intake sealed prior to shutting them down. Failure to do so can result in a considerable release of spores and other contaminants from the AFD’s filters back into the environment.
Draw makeup air from a clean source
When an area is maintained under negative pressure, makeup air equal in volume to the air exhausted is pulled in from somewhere. If this makeup air is pulled through cavities or pathways that are contaminated it may make it impossible to get the area being remediated to where it will pass a post remediation test. Always try to control the source of makeup air to the extent possible.
Mold Remediation Protocol
Indoor Environmental Technologies (IET) conducts a full mold investigation designed to determine the extent of water/mold damage to the property & to create a mold remediation protocol to provide guidance for the removal and repair of the damaged and affected areas. As we do not perform any remediation ourselves or have direct connections with remediation companies, we function as an “honest broker” providing defendable and dependable information.
Our services also include indoor air quality assessments, LEED certification testing, real estate inspections, industrial hygiene surveys, etc. We have provided these services in the Tampa Bay area, throughout the state of Florida, Southeast US & Caribbean. Contact us today!