Negative air required to contain mold contamination

Basement Flooding South Philadelphia

Property Recovery 911 was contacted by a homeowner in South Philadelphia to investigate, diagnose, mitigate and propose a solution to persistent basement flooding. Prior to our inclusion, the homeowner approached the insurance carrier about making a claim. The field adjuster informed the owner that groundwater was the source of basement flooding, which was not covered under the policy. The field adjuster then suggested that the homeowner, at the homeowner’s expense, hire a specific contractor to install a French drain around the basements entire periphery.

Basement Flooding & Ground Water

When faced with basement flooding, the insurance company adjusters first inclination will always be to declare ‘ground water’ the cause of the problem as it is rarely covered. Ground water is only covered by National Flood Insurance, which is a separate entity from your homeowners’ insurance company and normally only purchased in flood prone areas. In some instances, insurance companies offer a ‘sump pump rider’ that gives nominal coverage in the event of a sump pump failure.

Faced with this expensive undertaking that would have caused massive collateral damage as a result of the complete deconstruction of a finished basement, the homeowner reached out to Property Recovery 911 for a second opinion. After a cursory investigation, we quickly diagnosed the flooding to be the result of a failed wax ring connecting the toilet to the waste pipe in the basement powder room. This cause of loss was covered under the homeowner’s insurance policy and as a result we were able to demand full coverage for our client.

This issue was not readily apparent as the finished basement floor consists of ¾” plywood raised by 2”x4” pine creepers. As a result, water associated with the flooding was initially discovered by chance when the homeowner accessed a crawlspace used for long term storage and noticed water at the union between raised floor and the unfinished crawlspace.

The exposed building materials that could be seen from within the aforementioned storage area displayed signs of mold contamination, which indicated to us that flooding had been active for several weeks prior to being discovered. In order to protect the health of our client our first task was to build full containment and put the entire area under negative pressure.

Containing Mold Contamination

Building containment and establishing negative pressure required not only the construction of a containment chamber, but also an exit chamber. In order to enter containment, one was first required to enter and seal the exit chamber prior to accessing the work area. This fail-safe was necessary in order to maintain constant negative pressure, which is standard practice to protect the area outside of containment from mold contamination.

In order to create an air tight environment, containment was created using 6 millimeter fire retardant polyethylene held in place with a combination of Zip Poles and double sided tape. Each enclosure was then fitted with heavy duty zipper access. Finally, negative pressure was established by ducting out an air scrubber to extract air from containment. This process creates a vacuum by pulling air out of containment that is then purified as it passes through the pre-filter and HEPA filter within the air scrubber.

Once established, 7 Pascal’s of negative pressure is achieved by adjusting the air scrubbers variable speed motor and is measured as well as monitored with a differential pressure recorder known as a manometer. The extensive preparations outlined above are essential to insuring that unaffected areas of the living environment remain protected during mold remediation.

The presence of mold is always associated with a water event of some kind and in many instances, water mitigation and structural drying are necessary prior to mold remediation. Whether chronic or sudden, mold contamination is symptomatic of a moister problem and will persist until the source of moisture is corrected. As outline above, the basement flooding in this instance was caused by a failed wax ring connecting the toilet to the waste pipe in the basement powder room necessitating deconstruction, water mitigation and structural drying prior to mold remediation.

Deconstruction & Water Mitigation

Initially we performed what is known as a ‘flood cut’ in the powder room, which is a process whereby sheet rock is removed to a point above where water has traveled. Flood cuts are usually measured at 2 or 4 feet in order to facilitate reconstruction. The mold contaminated sheet-rock was then bagged in containment and removed from the premises followed by Structural drying of the exposed wood studs.

During the job consultation, we advised the homeowner that the tile floor and sub-floor in the powder room as well as in the adjacent laundry room should be removed to expose and properly dry the floor creepers below. At the homeowner’s request, we reluctantly deployed specialized cavity drying equipment in an attempt to save the above described floor coverings. The challenge with this method of structural drying is that the building materials trapped beneath the intact floor coverings could not be accessed to perform daily moisture readings providing no concrete proof of drying success within the cavities.

Mold Remediation Techniques

Once dried, the exposed building materials were treated with Serum 1000 laced with an enzymatic catalyst.

“Serum 1000 is a surface and substrate cleaner for removal of organic contamination. It accomplishes this by the use of 20% hydrogen peroxide formulated with surface active agents. This formulation allows Serum 1000 to break surface tension to penetrate deep into the substrate of porous materials. The Serum 1000 reacts with organic matter to generate profuse foam boiling the contamination to the surface for removal via HEPA vacuuming. Serum 1000 also reacts with the organic contamination on the surface generating profuse foam, breaking everything loose from the surface and up into the foam for removal via HEPA vacuuming. Serum 1000 may be applied to any surface not harmed by water. Serum 1000 doesn’t leave behind any toxic or hazardous chemicals. Serum 1000 degrades to water and oxygen. There is nothing left behind to gas off after drying. NO VOC’s.”

Serum 1000 literally boils mold contamination out of porous surfaces, lifting it out into the generated foam. After an hour of air drying, all surfaces were HEPA vacuumed to remove the loosened organic material. Our next step following mold remediation, was to encapsulate the cleaned building materials with Sentinel 24/7 Zero.

“Sentinel’s 24-7 ZERO is a new product which has zero V.O.C.’s, zero HAP’s, low odor high-performance coating with antimicrobial protection, designed to inhibit the growth of stain and odor causing mold, mildew, and other microorganisms on the coating film. It is excellent for high traffic areas, very durable & scrubbable. 24-7 ZERO is designed to be used on properly prepared woodwork, doors, walls, ceilings, plaster, sheetrock, concrete and other interior surfaces, including HVAC ducting. 24-7 ZERO is not intended for exterior use, or use on floors, unprimed metal surfaces, or in highly corrosive environments. Sentinel 24-7 Zero is available in a white or clear finish.”

Investigating Mold Contamination

Although compelled to abide by limitations imposed at the homeowner request with regard to job scope, such modifications can lead to complexities and complications that may ultimately compromise job quality. For this reason, we convinced the homeowner to allow us to perform an exploratory investigation at our own expense. Removing a section of the sill plate between two wall studs to examine the inaccessible underside and inside edge, we discovered a high moisture content and mold contamination on both inaccessible sides. We also found that within the floor cavities was closed cell rigid foam insulation, which undoubtedly impeded our injection drying efforts.

Because the wall studs and floor creepers were not installed in concert, the rigid foam insulation within was bisected in the middle of a stud making clean and complete removal of a single foam insulation panel impossible. As a result we were required to scrape out what we could with the tools at hand to make an avenue through which to insert our borescope for a more thorough investigation. The images revealed considerable mold contamination covering the building materials within the floor cavity.

Following a photographic presentation of our findings to the homeowner, we were given permission to remove the entire powder room floor as well as a portion of the family room floor just outside the powder room. We were informed that the laundry/utility room floor must remain intact no matter the circumstances. Although we advised that this decision should be made after the powder room floor was removed giving us access to the area beneath the laundry room, it was clear that the homeowner was adamant.

Additional Services

The powder room floor, consisting of terracotta tile over a simulated wet bed on ¾” plywood raised atop 2”x4” floor creepers, was demolished within containment and under negative pressure as described above. Everything was bagged in containment, securely sealed and removed from the premises. With the powder room floor out, we were able to slide out the rigid foam panel insulation beneath the laundry room. Staining on the rigid foam panels indicated that moisture had flowed approximately twelve inches beneath the laundry/utility room floor.

Since we were not permitted to remove the laundry/utility room floor, we were required to devise a method to dry from beneath and this would need to be done from the powder room. Due to space restrictions, drying beneath the utility room commenced after the powder room drying process was complete. We ducted two 20,000 BTU heating units and one Dri-Eaz 7000 Xli dehumidifier into the exposed floor cavities and sealed the floor cavities with a sheet of 6 mil. fire retardant poly to trap the heat within. We drilled pairs of holes in the grout lines between the tile in the utility room and used a hammer probe to measure moisture content in the plywood sub-floor below.

Once the cavities beneath the laundry/utility room floor were dried within 3 percentage points of dry standard, mold remediation of the previously inaccessible areas commenced. As described above, mold remediation required the application of catalyzed Serum 1000, agitation, HEPA vacuuming and encapsulation. Water mitigation, structural drying and mold remediation being successfully completed, the homeowner enlisted Property Recovery 911 for the rebuild.

Rebuilding

Reconstruction began with the installation of a new and far more robust floor creeper system. We felt the extra support necessary to insure that there would be no movement whatsoever beneath the porcelain tile floor that would ultimately be installed. The spaces between the creepers were then fitted with new closed cell foam insulation and this was covered with ¾” plywood sub-flooring.

The ‘flood cut’ sheetrock was then repaired in the basement powder room as well as family room and both areas were primed and painted. We then fitted the powder room with HardieBacker cement board, which was fixed into place using a combination of thin-set mortar and specially manufactured HardieBacker screws. Tile was set with a marble sill at the bathroom entrance, this allowed to cure overnight then the floor was grouted. After allowing the grout to dry overnight, we installed a new toilette, vanity, towel bar and bathroom tissue holder.

Property Recovery 911 is committed to assisting victims of disaster protect their interests by quickly removing the source of damage and starting the restoration. Our emergency restoration and preservation services include water mitigation, fire restoration, mold remediation and board up. We are available any time of day or night 365 days a year with 24/7 live phone support. Contact us at (267) 808-7200 for prompt, professional emergency restoration services.

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