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.
STRIPPING AND REPAINTING IRON AND STEEL FEATURES
A. This procedure includes guidance on stripping iron and steel of all paint build-up and repainting.
B. See 01100-07-S for general project guidelines to be reviewed along with this procedure. These guidelines cover the following sections:
1. Safety Precautions
2. Historic Structures Precautions
4. Quality Assurance
5. Delivery, Storage and Handling
6. Project/Site Conditions
7. Sequencing and Scheduling
8. 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).
A. The Benjamin Moore Co.
B. Devcon Corporation
C. The Sherwin Williams Co.
A. Metal Filler: Steel filled, two part, epoxy, metal filler, putty grade such as "Plastic Steel" (Devcon Corporation), or approved equal.
B. Paint for Metal: Alkyd resin, (Benjamin Moore), (Sherwin Williams), or approved equal, designed specifically for exterior metal application. Paint products shall be fresh and well-ground; shall not settle readily, cake or thicken in the container; shall be broken up readily with a paddle to a smooth consistency and shall have easy application properties. Other painting materials such as linseed oil, turpentine, mineral spirits, and miscellaneous thickeners, shall be of the highest quality and of an approved manufacturer. See also 05010-13-S for additional guidance on primers and paints for steel.
1. Primer: Compatible with top coats of paint; make each coat clearly different in color.
2. Base and Finish: Alkyd resin semi-gloss: Benjamin Moore or Sherwin Williams; make colors clearly different from each other and primer.
3. Dry Film Thickness:
a. Primer: 2 mils.
b. Base and Finish Coats: 2 mils each.
C. Sealant Backer Rod: Polyethylene compressible rod, 50% larger in diameter than the joint.
D. Sealant: Polyurethane sealant, color to match masonry.
A. Wire Brush: Non-ferrous metal brush such as brass.
B. Dry Grit Blasting: Fine grit at 80-100 psi.
C. Paint brushes
1. Enclose dry-grit blasting work areas with temporary scaffolding or framework sufficient to support tarpaulin enclosure to prevent escape of abrasive.
2. Shield adjacent masonry and glass with a temporary covering of cardboard or fiberboard held in place with heavy-duty strapping tape or wood bracing. Use drop cloths or other suitable coverings as appropriate to protect materials from paint drips and splatters.
B. Surface Preparation:
1. Determine that surfaces to which paint is to be applied are even, smooth, sound, clean, dry and free from defects affecting proper application. Correct or report defective surfaces to Contracting Officer.
2. Execute all painting in a temperature range of 50 - 85 F, at a relative humidity below 60%. Do not apply paint on surface in direct sunlight or in spaces where dust is being generated which would speck the finish.
3.02 ERECTION, INSTALLATION, APPLICATION
A. Remove all paint to bare metal from iron and steel surfaces using mechanical methods such as scraping, sanding or dry grit blasting. See also 05010-05-R for additional guidance on paint removal from steel.
B. Remove dirt and grease and abrade remainder of the surface with wire brushing. Remove residual grit from all surfaces by air blasting.
C. Seal all open joints between metal elements and masonry with backer rods and sealant. Joint shall be concave with smooth finish. Do not allow sealant to extend over the edges of the metal or the face of the stone.
D. Replace or repair any badly deteriorated pieces of metalwork to match the original.
E. Fill small holes, depressions and cracks with metal filler following the manufacturer's written directions. Finish all filled areas by sanding flush, after curing time has elapsed.
D. Prime all metal within two hours of cleaning, down to bare metal using a color obviously different from the finish color.
F. Paint to match color specified by the RHPO.
1. Brush-apply material evenly without runs, sags, or other defects. Work each coat onto the material being coated at an average rate of coverage recommended in manufacturer's printed instructions.
2. Cover surfaces completely to provide uniform color and appearance with a minimum of dry, film thickness of 2 mils.
3. Make edges of paint, adjoining other materials or colors, sharp and clean and without overlaps.
4. Apply additional coats when undercoats, stains, or other conditions show through final coat of paint, until paint film is of uniform finish, color and appearance. Insure that corners, edges, crevices and exposed fasteners receive a dry film thickness equal to that of flat surfaces.
5. Each coat of paint is to be slightly darker than the preceding coat with the final coat exactly matching the accepted samples.
G. Drying Time: Minimum time, as recommended. Do not apply subsequent coats until the undercoat is thoroughly dry. Sand between coats to produce even and smooth surfaces.
A. Remove all paint where it has spilled or spattered. Do not drip any paint on stone. Use paint thinner or solvent as necessary to effect complete removal.