This is not a sustainable use of expensive lasers as they do cause abrasion to surfaces.
The National Park Service, the GSA and other bodies have long used D2 biocidal cleaner and deterrent on historic buildings and monuments. But no sound scientific reasoning has been given for not continuing to use this approach.
John F
John A. Fidler DipArch, MAarch, MAconservation, AAGradDiplconservation
RIBA, IHBC, Intl Assoc AIA, FRICS, FSA, FIIC, FAPT
John Fidler Preservation Technology Inc
Marina Towers North
4640 Admiralty Way, Suite 500
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USA
Tel: 310-496-5730
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Email: johnfidler@jf-pt.com
www.linkedin.com/pub/john-fidler/13/921/794
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