Dry-ice blasting is rapidly becoming the preferred method ofcleaning wood in the restoration industry due to its unparalleledresults and timesavings when compared to the usual methods ofsanding or scraping with a wire brush. Contractors are cuttingtheir project time by 60 percent or more per project. Thisinnovative cleaning process is gaining momentum in the field ofmold remediation, fire restoration, and historic buildingrestoration for its ability to thoroughly clean surfaces like wood,metal, or masonry, while leaving no additional waste to attendto.

Time is of the essence in a fire restoration project or a moldremediation project. Insurance companies, real estate and titlecompanies, and general contractors are all watching the clock whenit comes to restoring a building or home. The quicker the problemis alleviated, the quicker the residents of the building canreturn. Dry-ice blasting allows the contractor to restore thecontaminated building faster than any other method. Therefore, thedisplacement costs experienced by the insurance company are greatlyreduced.

Speeding up Restoration

Dry-ice blasting benefits the restoration contractor because itgrants access to tight and hard-to-reach areas in confined spaces,such as attics or crawl spaces. Conventional cleaning methodsrequire the contractor to manually sand, scrape, or wire brush themold or smoke damage from contaminated surfaces. This can be aslow, tedious, and generally unpleasant process. Dry-ice blastingresults in the complete removal of contaminants from these surfacesin less time than any other method. Dry-ice blasting saves thecontaminated wood, which with conventional cleaning methods, mayhave had to have been replaced.

SteamMaster began utilizing dry-ice blasting over three yearsago. Gary Gilman, president of SteamMaster, had researched dry-iceblasting approximately 15 years earlier for possible use in firerestorations and industrial cleaning. Since they purchased theirCold Jet dry-ice blasting system, the firm has successfullycompleted over 50 dry-ice blasting projects. Most of the company'smold remediation projects, which employ the use of this cuttingedge technology, include removing mold from attic and crawl spacesheathing, trusses and framing.

Tight-Spot Challenges

Dry-ice blasting is particularly effective where engineered roofor floor joists and decking are impregnated with mycelium, which isa tangled network of mold filaments. In a single pass, crews caneffectively and efficiently remove mold from multiple right-angledsurfaces that would be cumbersome and time-consuming to access withsanding or scraping. Brian Greenwood, a restoration technician,does most of the blasting for SteamMaster. He says, “The dry-iceblasting system provides our remediation crews with access to cleantight areas that may otherwise be unreachable, such as three- tofour-inch gaps in framing and rim joists above concrete-stemwalls.” He goes on, “Dry-ice blasting makes our job much easier andmore thorough and we can complete the job in less than half thetime.”

With regard to mold remediation, it is important to note thatapplying a biocide to a contaminated surface to kill the mold doesnot replace the need for an effective cleaning. The allergens inmold are not always being eliminated with a biocide, rendering deadmold as allergenic and in need of removal. Typically, enough sporesare left behind that if the moisture problem is not corrected, themold will re-grow in time. In addition, these biocides aretypically registered pesticides and are potentially harmful tothose using them. The EPA and OSHA do not recommend routine use ofbleach or other biocides in mold remediation. To eliminate theallergenic properties associated with mold, it is necessary toremove it from the contaminated surface. This can be done with thetraditional method of sanding and scraping, or with the morethorough and more efficient option of dry-ice blasting. Dry-iceevaporates completely as a gas, so only the mold being removed mustbe disposed of.

Thermal Shock Effect

As it accelerates dry-ice particles into a pressurized airstream to impact the surface being cleaned, it will not interruptany electric compounds or wiring and it will not cause toxic harmto the operator. Traditionally, dry-ice blasting has been used toclean specific production applications for its thermal shockeffect. The dry ice is at a temperature of minus 109.3 degreesFahrenheit or minus 78.5 degrees Celcius, and as it blasts againstthe contaminant it causes it to shrink and lose its adhesion fromthe substrate. With regard to cleaning a wood surface, dry-iceblasting works somewhat like sandblasting or high-pressure waterblasting, but with superior results, as there will be no mediaresidue to clean up at the completion of the project.

Dry-ice blasting will typically remove about 3 percent of thewood's surface being cleaned, so it is using kinetic energy and ascrubbing action to clean. This blasting application effectivelyremoves the contaminant, while rarely altering the structuralintegrity of the wood. Since there is no secondary waste stream toattend to, the only thing left to do is vacuum the residualcontaminant and wood that was removed from the blasting.

Necessary Precautions

With any restoration project, it is crucial to take thenecessary precautions with regard to the safety of the remediationcrew. Proper personal protective equipment should be worn and thearea being treated will need to be properly sealed off so that thecontaminant does not fly into other nearby, non-contaminated areas.Caution must be employed to manage oxygen levels in confined areas.Restoration crews should vent fresh air into the work area andexhaust the build-up of carbon dioxide gas to the outside. Anegative air flow environment with HEPA filtration is recommendedin confined attics and crawl spaces to ensure the operator'ssafety.

Dry-ice blasting is a more efficient cleaning method thansanding or scraping. It is also better suited for mold remediationthan any other type of blasting, such as sand blasting, waterblasting, or soda blasting. Sand blasting is known as an effectivecleaning method. However, it is far too abrasive and damaging tothe underlying surface being treated. So, after dry-ice blastingthe structural integrity of the surface being cleaned is usuallyleft in tact. Water and steam blasting do not provide as thorough aclean as dry-ice blasting does, and there is a greater chance ofcausing further damage to the substrate, due to the water vapor andmoisture component. Soda blasting is an effective, although messy,cleaning method with regards to restoration. However, the maindrawback with soda blasting applies to the other blasting methodsas well. It leaves behind a secondary waste stream to be attendedto, creating additional cleaning to be done and adding time andcost onto the project. With dry-ice blasting, the carbon dioxidegas sublimates into the atmosphere after it impacts the surfacebeing cleaned, leaving no additional waste streams to disposeof.

Dry-ice blasting is a fresh approach to Restoration and iscurrently being used by many remediators in various parts of thecountry. Its ability to clean surfaces thoroughly and efficientlyis an irresistible alternative to sanding and scraping. While thereare costs associated with buying the equipment, these costs areoutweighed by the labor-saving benefits. Generally speaking, theseblasting systems have reduced the time it takes to completerestoration projects. Because of the drastic reduction in cleaningtime resulting from dry-ice blasting, firms can dramatically boosttheir revenues as well.

Gary Gilman is president and founder of SteamMasterRestoration & Cleaning, Vail, Colo. He is a Certified MoldRemediator and has been remediating mold from structures since1984. Contact him at 800-527-1253, www.steammaster.com.

Tina Moore is the marketing specialist at Cold Jet, LLC. Formore information on dry-ice blasting, call 513-831-3211,www.coldjet.com.