The historic restoration of Boston's Longfellow Bridge is now complete! The large-scale granite restoration project included onsite blasting by United Stone, as well as dismantling the bridge’s iconic Rockport granite “salt and pepper” towers piece-by-piece, and then transporting them to nearby workyards in Charlestown via barge for offsite restoration. The now pristine towers were reassembled using a mix of modern and historic construction technology. Skilled masons at United Stone were able to clean ornate granite carvings as well as the large granite blocks using the same equipment and media.
Restoring Granite with Sponge-Jet is a straight forward process. Once an ideal finish is chosen by an architect or conservator, sponge blasting can be customized to meet the requirements through media and blast pressure selection. Micro-abrasives clean the surface without damaging the stone, removing staining, chlorides, and other contaminants.
Airborne dust is limited at the point of generation, making a typically dusty process very manageable. Parts of the Longfellow Bridge were able to remain open throughout the restoration process. The Bridge was open to pedestrians and bicyclists with blasting taking place just meters below.
Jeff Hartwell, VP, Operations for United Stone and Site Inc. offered, “The Sponge-Jet system has worked great for us on the Longfellow Bridge and other projects. Once initial setup is in place, the system can do its job with a two-man crew depending on access. You can’t say enough about the eco-friendly aspect of the Sponge Media. All in all you would have to force us to go back to acidic cleaners or conventional bucket and brush-cleaning.”