U.S. General Services Administration
Technical Procedures Disclaimer
Prior to inclusion in GSA’s library of procedures, documents are reviewed by one or more qualified preservation specialists for general consistency with the Secretary of Interior Standards for rehabilitating historic buildings as understood at the time the procedure is added to the library. All specifications require project-specific editing and professional judgement regarding the applicability of a procedure to a particular building, project or location. References to products and suppliers are to serve as a general guideline and do not constitute a federal endorsement or determination that a product or method is the best or most current alternative, remains available, or is compliant with current environmental regulations and safety standards. The library of procedures is intended to serve as a resource, not a substitute, for specification development by a qualified preservation professional.
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We’ve reviewed these procedures for general consistency with federal standards for rehabilitating historic buildings and provide them only as a reference. Specifications should only be applied under the guidance of a qualified preservation professional who can assess the applicability of a procedure to a particular building, project or location. References to products and suppliers serve as general guidelines and do not constitute a federal endorsement nor a determination that a product or method is the best alternative or compliant with current environmental regulations and safety standards.
PART 1–GENERAL
1.01 SUMMARY
A. This procedure includes guidance on re-polishing eroded areas in exterior granite.
B. See 01100-07-S for general project guidelines to be reviewed along with this procedure. These guidelines cover the following sections:
- Safety Precautions
- Historic Structures Precautions
- Submittals
- Quality Assurance
- Delivery, Storage and Handling
- Project/Site Conditions
- Sequencing and Scheduling
- General Protection (Surface and Surrounding)
These guidelines should be reviewed prior to performing this procedure and should be followed, when applicable, along with recommendations from the Regional Historic Preservation Officer (RHPO).
1.02 SUBMITTALS
A. Product Data: Submit manufacturer’s technical data for each product indicated including recommendations for their application and use. Include test reports and certifications substantiating that products comply with requirements.
1.03 PROJECT/SITE CONDITIONS
A. Environmental Requirements: Perform work only in dry and otherwise favorable weather conditions. Protect repaired stone against freezing or excessively rapid drying for at least 48 hours after being laid; no masonry shall be laid when temperature is below 32 degrees F on a rising thermometer or below 40 degrees F on a falling thermometer.
B. Existing Conditions: Contractor shall take whatever precautions are necessary to protect the existing building from damage resulting from work under this section.
PART 2–PRODUCTS
2.01 MATERIALS
A. Grinder with silicone carbide grinding stones or diamond disks.
B. Aluminum oxide polishing compound
C. Felt pads
D. Clean, soft cloths
E. Clean, potable water
PART 3–EXECUTION
3.01 ERECTION, INSTALLATION, APPLICATION
NOTE: THIS WORK SHALL ONLY BE PERFORMED BY A SKILLED GRANITE REFINISHING CONTRACTOR.
A. Grind granite down until an even plane is achieved. Feather out to unaffected surface as required to avoid granite having dished appearance. Use right angle water feed grinder with successively finer diamond disks (#60 to #3500) or silicon carbide grinding stones (36 to 400 grit).
B. Polish to match existing sheet of granite. Use acid free aluminum oxide polishing compound with felt pad.
CAUTION: POLISHING COMPOUNDS CONTAINING FLUORIC ACID WILL EVENTUALLY ETCH THE GRANITE SURFACE, RESULTING IN A DIMINUTION OF GLOSS.