As more is understood about the health issues related to mold growth in interior environments, new methods for mold assessment and mold remediation are being put into practice.
Mold assessment is the process of identifying the location and extent of the mold hazard in a structure. This is typically performed by a certified mold inspector or environmental hygienist. Mold remediation is the process of cleanup and/or removal of mold from an indoor environment. Mold remediation is usually conducted by a company with experience in construction, demolition, cleaning, airborne-particle containment-control, and the use of special equipment to protect workers and building occupants from contaminated dust and organic debris.
A new method that is gaining traction is soda blasting or dry ice blasting for mold removal.
Soda blasting and dry ice blasting for mold removal are also known as abrasive blasting or media blasting. Water blasting, sand and grit blasting, glass bead blasting, and corn cob blasting are other alternative medias that can be used in lieu of sodium bicarbonate or dry ice particles.
Abrasive blasting is a process for cleaning or finishing objects by using an air-blast or centrifugal wheel that throws abrasive particles against the surface of the work pieces. For the purposes of mold remediation, sodium bicarbonate (baking soda) and dry ice are the media commonly used.
Abrasive blasting is commonly used in attics and crawl spaces where it is difficult to perform other types of mold remediation. It is also used for some types of outdoor mold situations as well as mold in storage sheds and storage units.
Benefits of Abrasive Blasting
Soda blasting or dry ice blasting provides some distinct advantages over traditional techniques of mold remediation. In addition to eliminating much of the tedious labor involved in scrubbing and sanding by hand, abrasive blasting is extremely useful for cleaning irregular and hard-to-reach surfaces. Surfaces that have cross-bracing or bridging can be cleaned more easily, as well as areas such as the bottom of a deck, where nails may be protruding. Areas that are difficult to access, such as attics and crawlspaces, can also be cleaned more easily with abrasive blasting than by traditional methods. The time saved is also an advantage, and the typical time frame for completion of a mold remediation project can often be greatly reduced by utilizing abrasive blasting.
If you have been wondering “does soda blasting kill mold” or “does dry ice blasting kill mold” then the answer is no. It doesn’t kill it. But it does remove it better than most other techniques. Let’s take a look at various abrasive blasting techniques in greater detail.
Soda-Blasting For Mold Removal
Soda-blasting is a type of abrasive blasting that utilizes sodium bicarbonate as the medium propelled by compressed air.
One of the earliest and most widely publicized uses of soda-blasting was on the restoration of the Statue of Liberty. In May of 1982, President Ronald Reagan appointed Lee Iacocca to head up a private-sector effort for the project. Fundraising began for the $87 million restoration under a public-private partnership between the National Park Service and The Statue of Liberty-Ellis Island Foundation, Inc. After extensive work that included the use of soda-blasting, the restored monument re-opened to the public on July 5, 1986, during Liberty Weekend, which celebrated the statue’s centennial.
The baking soda used in soda-blasting is not the type you would purchase from a grocery store and bake with. This sodium bicarbonate is soft but angular, appearing knife-like under a microscope. The crystals are manufactured in state-of-the-art facilities to ensure that the right size and shape are consistently produced.
Baking soda is water-soluble, with a pH near neutral. Baking-soda abrasive blasting effectively removes mold while minimizing damage to the underlying surface (i.e., wood, PVC, modern wiring, ductwork, etc.). When using the proper equipment setup (correct nozzles, media regulators, hoses, etc.) and technique (proper air flow, pressure, angle of attack, etc.), the process allows for fast and efficient removal of mold, with a minimum of damage, waste and cleanup. By using a soda blaster with the correct-size nozzle, the amount of baking soda used is minimized. Minimal baking soda means better visibility while working, and less cleanup afterward.
The downside to soda blasting is that when not done correctly (see above), it produces a significant amount of extra fine dust and leaves a great deal of secondary waste from the blast media that has to be recovered and removed. This adds additional time and cost to the mold removal project. Additionally, the waste can create downstream contamination that could affect surrounding installations and kill surrounding vegetation.
Dry-Ice Blasting For Mold Removal
Dry ice is solidified carbon dioxide that, at -78.5° C and ambient pressure, changes directly into a gas as it absorbs heat. Dry ice pellets are made by taking liquid carbon dioxide (CO2) from a pressurized storage tank and expanding it at ambient pressure to produce snow. The snow is then compressed through a die to make hard pellets. The pellets are readily available from most dry ice suppliers nationwide. For dry-ice blasting, the standard size used is 1/8-inch, high-density dry ice pellets.
The dry-ice blasting process includes three phases, the first of which is energy transfer. Energy transfer works when dry ice pellets are propelled out of the blasting gun at supersonic speed and impact the surface. The energy transfer helps to knock mold off the surface being cleaned, with little or no damage.
The freezing effect of the dry ice pellets hitting the mold creates the second phase, which is micro-thermal shock, caused by the dry ice’s temperature of -79º C, between the mold and the contaminated surface. This phase isn’t as much a factor in the removal of mold as it is for removing resins, oils, waxes, food particles, and other contaminants and debris. For these types of substances, the thermal shock causes cracking and delaminating of the contaminant, furthering the elimination process.
The final phase is gas pressure, which happens when the dry ice pellets explode on impact. As the pellets warm, they convert to CO2 gas, generating a volume expansion of 400 to 800 times. The rapid gas expansion underneath the mold forces it off the surface.
Dry ice blasting is the preferred abrasive blasting method both for homeowners and remediation companies. Unlike other media blasting methods, dry ice blasting does not leave much secondary waste. It is safe, non-toxic and eliminates exposure to harmful chemicals.
In addition dry ice blasting will not cause significant structural damage to the contaminated surface. For example, when blasting on wood, it will typically remove about 1/32 of the wood’s surface while being cleaned, as it is using kinetic energy and a scrubbing action to clean. This blasting application is enough to effectively remove the mold spores, but not enough to alter the structural integrity of the wood in the contaminated area. This is important when using dry ice blasting for attic mold or crawl space mold.
Dry ice blasting has shown to completely remove mold spores from contaminated surfaces in less time and with less effort than other cleaning methods. Contractors can get in between beams, into roof sheathing and other tights areas, allowing for complete mold spore removal and eliminating the need for encapsulation and biocides.
Sand and Grit Blasting For Mold Removal
Sand and grit blasting are considered aggressive cleaning methods and are used more frequently for rusted surfaces, graffiti removal, coatings, surface preparation or floor cleaning. While sand and grit blasting disturb the mold spores, these methods can be too aggressive and the mold is often broken up into smaller particles, which can pass through a HEPA (High-Efficiency Particulate Air) filtration system and contaminate other areas. The abrasive media can also damage the underlying surface that is being cleaned. Additionally, the media is a secondary waste that must be collected and disposed of when cleaning is complete.
Steel, silicone, walnut shell, and corn cobs are all grit options used in sand and grit blasting for mold removal.
Water Blasting For Mold Removal
Water blasting is commonly used in air duct cleaning and is typically ineffective if the mold particles are adhered to the surface. It does not provide as thorough a removal of mold spores as other blasting methods, and there is a greater chance of mold regeneration due to the moisture component. If you are offered the option of water blasting, I would decline and choose another abrasive blasting media.
How Long Does Abrasive Blasting Take?
Soda blasting and dry ice blasting are typically a three day process. Day one is for set up. Day two is for blasting and drying. Day three is for cleanup.
The Importance Of HEPA Vacuuming After Abrasive Blasting
While abrasive blasting with either baking soda or dry ice is an effective technique to remove mold, remediation will not be complete until HEPA filtering or vacuuming has been done.
A HEPA vacuum is a vacuum cleaner with a high-efficiency particulate air (or HEPA) filter through which the contaminated air flows. HEPA filters, as defined by the U.S. Department of Energy’s standard adopted by most American industries, remove at least 99.97% of airborne particles that are as small as 0.3 micrometers (µm) in diameter. HEPA vacuuming is necessary in conjunction with blasting for complete mold removal.
Abrasive blasting removes mold from contaminated surfaces, but it also causes the mold spores to become airborne again. The spores can cover the ground and the surfaces that have already been cleaned. So, the mold spores need to be removed by HEPA filters. Additionally, while some remediation companies claim that there will be no blasting media to remove after cleaning, especially with the dry-ice method, there will be at least a small amount of visible debris left by the blasting that must be removed before HEPA vacuuming can occur. HEPA vacuuming removes all invisible contaminants from surfaces and the surrounding air. When HEPA vacuuming is completed, samples at the previously contaminated areas should be re-tested to ensure that no mold or mold spores remain.
How Much Does Dry Ice Blasting or Soda Blasting Cost?
Accepted insurance/restoration industry estimating programs almost always base the billing on the actual square footage that the contractor cleans. Most programs also differentiate between levels of cleaning (i.e. “regular,” “heavy,” and “extra-heavy” media blasting) with different billing amounts.
It is important to note that the surface area is not just the square footage of the foundation of your home. It includes other surfaces – roof decking, trusses, joists, walls, etc. These all add up to the square footage to be cleaned, or the billable amount.
There is no industry standard when it comes to the amount billed per square foot for soda blasting or dry ice blasting. It is best to check with different companies and get a quote from at least three.
Can I Remove Mold With Dry Ice Blasting Or Soda Blasting Myself?
If you just happen to have all the right equipment then go for it. Otherwise, you will want to hire a professional. There is a big learning curve to using the equipment to correctly blast away all of the mold.
Soda Blasting and Dry Ice Blasting For The Win
The first step in combating mold growth is not to allow for an environment that is conducive to its growth in the first place. You know, basic mold prevention. Controlling moisture and assuring that standing water from leaks or floods is eliminated are the most important places to start. If mold growth has already begun, the mold must be removed completely and any affected surfaces must be cleaned or repaired. Abrasive blasting using dry ice or baking soda, combined with HEPA-filter vacuuming, is an effective method for mold remediation in many areas of your home and should be considered as part of your overall mold remediation plan.