Advanced Stone Restoration Technician (NSI) Stone restoration pros handle everything from identifying marble degradation on historic facades to removing biological growth from granite countertops. NSI certification confirms you can execute the technical work—assessment, cleaning methods, sealant application, structural repair—that clients expect. You’ll work across residential kitchens, commercial lobbies, and architectural landmarks where precise technique prevents costly mistakes.
| Exam Name | Advanced Stone Restoration Technician |
| Exam Code | NSI |
| Format | PDF & Practice Test Engine |
| Target Year | 2026 Updated |
| Features | 100% Verified Q&As |
