The Basics of Mold Remediation – Part II of III – Gross Removal of Mold Growth and Impacted Materials
See my post "The Basics of Mold Remediation – Part I of III – Containment of the Affected Area" 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. The next step is to perform the removal of impacted materials and mold growth.
Part II of III – Gross removal of mold growth and impacted materials
Unfortunately, when a mold problem is present within a home it typically means that some materials are going to have to be removed. If mold growth is within a wall cavity or under flooring materials, to be accessed, the materials around the source must be removed. If mold and/or water damaged non-structural materials are present, they are typically removed and discarded. These types of materials would include: baseboards, drywall, carpeting, carpet pad, tack strip, underlayment, insulation, building paper, etc. The bottom line is that most remediation projects involve the demolition of building materials. The removal of materials is typically well planned and, on most projects, only the necessary materials will be removed while salvaging the non-affected materials.
Once the removal of the non-structural materials is accomplished, mold growth must be cleaned and removed from the structural materials. Mold is often found growing on organic structural materials such as framing, subflooring, roof sheeting and just about any organic material that is used in construction. As long as the structural integrity of these materials has not been compromised, the mold growth will be cleaned and removed from the materials. The first step in this process is to HEPA vacuum the surface of these impacted materials. This is done to remove as much of the mold source as possible in a controlled manner in an effort to prevent the mold spores from becoming airborne. Next, the impacted materials are scrubbed and cleaned to remove all physical mold growth. This is a very important step because mold sources imbed themselves into the materials they are feeding on with hyphae. Hyphae are thread like components of the mold used to bind itself to the material and can penetrate it as far as a 1/32nd of an inch. Some contractors will remove the hyphae with wire brushes or sanding, while others may use more intense methods such as dry ice blasting or media blasting. Either way, the mold must be removed in its entirety. This process typically creates lots of dust and debris, so HEPA vacuuming is often done in combination with the cleaning.
During the cleaning of the structural materials, many contractors use liquid based cleaning products in combination with the cleaning. This is done for multiple reasons: to physically kill the mold, to penetrate the affected materials and aid in loosening the hyphae, to wet the mold source and make the spores less likely to become airborne, to bleach the materials and remove evidence of staining, etc. There are many different types of products used: some are “Green” products considered to be environmentally safe, some are biocides designed to kill all biological organisms, some are fungicides designed to kill fungal based organism, and some are based on everyday homeowner liquids such as Hydrogen Peroxide (quite a bit stronger then the stuff in your medicine cabinet though).
Once all of the impacted non-structural materials have been removed, and all of the physical mold growth has been cleaned and removed from the structural materials, the next step of the remediation project may begin. Stay tuned Part III of a basic mold remediation project…