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.
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.
- This procedure includes guidance on restoring metal leaf on existing plaster surfaces and includes cleaning and repairing damaged metal leaf.
- 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
- 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).
- Product Data: Submit manufacturer's product specifications and installation instructions for each material, including other data as may be required to show compliance with these specifications.
- Operation and Maintenance Data: Submit written program for each phase of restoration process including protection of surrounding materials on building during operations. Describe in detail materials, methods and equipment to be used for each phase of restoration work.
1.02 PROJECT/SITE CONDITIONS
- Environmental Requirements:
- Monitor environmental conditioning throughout construction period. Notify owner if environmental conditions vary beyond minimum or maximum allowable conditions.
- Dispose of by-products from cleaning and paint stripping operations by legal means and in manner which prevents damage to other surfaces.
- Existing Conditions: Protect surrounding surfaces from damage resulting from chemical cleaning and paint stripping work.
- Liquitex, Inc., www.liquitex.com/
- Conservation Resources International LLC, www.conservationresources.com/
NOTE: Chemical products are sometimes sold under a common name. This usually means that the substance is not as pure as the same chemical sold under its chemical name. The grade of purity of common name substances, however, is usually adequate for stain removal work, and these products should be purchased when available, as they tend to be less expensive. Common names are indicated below by an asterisk (*).
- Protective Coating for Metal Leaf: Varnish designed specifically for finishing decorative paintings, such as "Soluvar" (Liquitex, Inc.), or approved equal.
- Use a finish to match existing.
- Thin varnish with paint thinner - one part varnish to three parts thinner.
- Paint thinner such as mineral spirits or turpentine Mineral Spirits:
- A petroleum distillate that is used especially as a paint or varnish thinner.
- Other chemical or common names include Benzine* (not Benzene); Naphtha*; Petroleum spirits*; Solvent naphtha*.
- Potential Hazards: TOXIC AND FLAMMABLE.
- Safety Precautions:
- AVOID REPEATED OR PROLONGED SKIN CONTACT.
- ALWAYS wear rubber gloves when handling mineral spirits.
- If any chemical is splashed onto the skin, wash immediately with soap and water.
- Available from construction specialties distributor, hardware store, paint store, or printer's supply distributor.
- Typically used as a solvent and thinner.
- Potential Hazards: TOXIC AND FLAMMABLE.
- Safety Precautions:
- Work in a well ventilated area.
- Observe safety rules as turpentine is flammable, and the fumes can trip an ionization smoke detection system.
- Store soiled cloths in a metal safety container to guard against spontaneous combustion.
- Available from hardware store or paint store.
- Metal Leaf Solvent Cleaner: 1,1,1, trichloroethane
- Metal Leaf Sizing: Fast-tack sizing designed specifically for installation of metal leaf
- Gilding: Tissue booklet of metal leaf - available in "patent" leaf (secured within a book) or "loose" leaf
- Japan Color: Yellow ochre or other color pigment in a varnish base to match desired color
- Clean, soft cotton balls
3.01 ERECTION, INSTALLATION, APPLICATION
- At locations indicated, clean and conserve existing gold or silver leaf on existing plaster surfaces.
- Saturate a rolled cotton ball with solvent cleaner and squeeze out excess.
- Gently rub metal leaf surfaces to remove accumulated dirt. Replace cotton ball frequently.
- Continue rubbing as required to produce effect established by mock-up in a uniform manner over entire surface.
- Repair missing or damaged areas by installing new metal leaf material.
- Clean surface and sand where required to create a smooth finish.
- Apply a coat of Japan color over area.
- Apply a thin coat of sizing to the surface.
- Once proper tack of sizing is reached, position metal leaves.
- Smooth leaves and remove excess with a soft brush. Fill in small spots where leaf did not stick.
- If gold color is required on silver leaf, apply two coats of orange shellac to surface of silver leaf to tint similar to adjacent surface.
- See also 05010-27-R for guidance in applying metal leaf.
- Apply two coats of protective coating to surface to comply with manufacturer's instructions.
- Upon completion of this work, all floors, walls, and other adjacent surfaces that are stained, marred, or otherwise damaged by work under this section shall be cleaned and repaired and the adjacent areas shall be left in clean and perfect condition.
- All completed work shall be adequately protected from damage by subsequent building operations and effects of weather. Protection shall be by methods recommended by the manufacturer of installed materials and as approved by the RHPO.