In the early hours of a windy Sunday morning, a massive, 10-alarm fire broke out in the downtown area of Waltham, Massachusetts. The fire completely destroyed a condo complex that was under construction, leaving severe soot damage throughout the entire parking garage next door.
The concrete parking garage was designated parking for the condo complex that was burnt to the ground. More than 28,000m² (300,000ft²) of walls, ceilings and floors were completely covered with black soot. The garage had to be cleaned and decontaminated, without harming the newly built concrete structure.
Finding the Best Method for Soot Removal
The owners of the Waltham parking garage needed a cleaning process that would remove all the soot from the concrete, but not damage the surface or generate dust. Many soot cleaning processes were tried, including hand-cleaning and wiping, but that didn’t work, and the labor costs would have skyrocketed with manual cleaning.
Dry ice and baking soda didn’t achieve the desired results and didn’t properly protect the concrete. Power washing wasn’t a feasible option because this restoration project was to take place in January, so moisture penetration along with the freeze-thaw cycle had the potential to significantly damage the concrete.
After several unsuccessful attempts at cleaning and restoration, engineers considered Sponge Blasting as an alternative to traditional cleaning methods. Sponge-Jet Silver 80 Sponge Media™ was specified as the best fit for the job, as a gentle, effective cleaning method that would not generate dust or damage the substrate.
Preserving and Cleaning the Surface
Using Sponge Media, the contractor, APC Services of New England, was able to blast the entire garage using just 2.7 bar (40 psi) of air at the nozzle. Finding the best pressure for removing the soot was painless for APC as managing air pressure and media flow can be done at the blast pot.
“Sponge-Jet was able to provide a low dust, low waste-stream solution that enabled the contractor to complete the job quickly, within the concrete preservation values that were essential to success,” said Sponge-Jet's Tony Anni.
Cleaning Concrete with Low Dust
Low dust generation was critical for this job, as the parking garage is located in the heart of downtown Waltham, with many local residents and passersby in close proximity. In addition, there were other trades working on the new foundation for the adjacent condo rebuild, as well as working in the parking garage itself.
“Using Sponge Media, gave the other trades a great deal of scheduling flexibility to work near blasting because of the low dust generation and low waste stream. Overall, Sponge Media provided a high-quality, cost-effective, money-saving solution that worked for everyone involved,” said Anni.