Epoxy Patching Small Cracks and Holes in Marble

CSI Division
Division 4- Masonry
Section
Marble
Last Modified

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

  1. This specification provides guidance on patching small cracks and holes in marble with a two-component epoxy resin.

  2. This specification is appropriate for cracks smaller in width than 1/8” and for holes smaller in diameter than 2”.

  3. Small cracks and holes in marble or other stone may be caused by impact damage, natural flaws in the stone or work on the stone. A common cause of holes and cracks is the attachment of fixtures and signage to walls. The later removal of such attachments leaves unsightly anchor holes which should be plugged or patched.

  4. Read “General Project Guidelines” along with this specification. 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). The guidelines cover the following sections:

    1. Safety Precautions

    2. Historic Structures Precautions

    3. Submittals

    4. Quality Assurance

    5. Delivery, Storage and Handling

    6. Project/Site Conditions

    7. Sequencing and Scheduling

    8. General Protection (Surface and Surrounding)

PART 2–PRODUCTS

2.01 MATERIALS

  1. Patching Resin:

    1. Manufacturer’s standard 2-component epoxy resin, designed specifically for patching or bonding of marble units.

    2. Factors to consider when selecting an epoxy should include:

      1. Permeability

      2. Absorption

      3. Thermal expansion coefficients

      4. Ultraviolet lighting conditions

  2. Aggregate for Epoxy: Ground marble dust to match color of existing marble

  3. Clean, potable water

2.02 EQUIPMENT

  1. Hacksaw Blade

  2. Chisels

  3. Hand-held Water Bottle

  4. Steel Trowel

  5. Caulking gun

  6. Stiff bristle brushes (non-metallic)

  7. Resurfacing Screens for Honed Finish: A fine grit screen manufactured specifically for restorative type cleaning and resurfacing of honed marble surfaces.

  8. Grinding Stones for Honed Finish: Fine grit emery stones manufactured specifically for restorative type grinding and resurfacing of honed marble surfaces.

  9. Soft, nylon bristle brushes

PART 3–EXECUTION

3.01 ERECTION, INSTALLATION, APPLICATION

NOTE: THIS PROCEDURE IS APPROPRIATE FOR CRACKS SMALLER IN WIDTH THAN 1/8” AND FOR HOLES SMALLER IN DIAMETER THAN 2”. THE MAXIMUM SIZE OF THE REPAIR SHOULD BE ADJUSTED ACCORDING TO THE TYPE OF MARBLE AND THE PROPOSED APPEARANCE.

  1. Using a chisel or hacksaw blade, carefully remove unsound marble material and old patching material from cracks and holes to expose sound marble material for contact with epoxy patch.

  2. Brush, vacuum or flush cracks and holes to remove dirt and loose debris.

  3. Mix 2-component epoxy resin with marble dust aggregate to create a paste with a consistency suitable for application (based on RHPO approval). Use marble dust from stone pieces of the same type, color, etc.

  4. Using a caulking gun or spatula, apply patching material in cracks and holes as recommended by manufacturer to conform to adjacent marble surfaces.

  5. Allow patching material to cure for period recommended by manufacturer.

  6. Once patching material has hardened, grind and polish surface of patching material to match surface characteristics of adjacent marble.

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Last updated: Aug 13, 2017
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