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.
CAUTION: Mechanical/abrasive methods of cleaning may damage historic fabric. This method of cleaning should be performed only by an experienced professional and only upon approval from the regional historic preservation officer.
The cleaning or stripping of metals may involve the use of abrasives, liquids or solvents which may splash or run off onto adjacent materials. Take special care to protect all adjacent materials, and do not use this procedure on metals other than those specified in the summary.
Before undertaking any project involving paint removal, applicable state and federal laws on lead paint abatement and disposal must be taken into account and carefully followed. State and federal requirements may affect options available to owners on both paint removal and repainting. These laws, as well as any requirements prohibiting volatile organic compounds (vocs), should be requested from the (from preservation brief 28, "painting historic interiors".) The environmental protection agency (epa) regional office and/or the state office of environmental quality.
- This procedure includes guidance on filling open cracks, cleaning and painting iron lamp standards.
- For information on inspecting for cast-iron failures, see 05010-01-S. For general information on the characteristics, uses and problems associated with cast- iron, see 04720-01-S.
- 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).
- The Society for Protective Coatings (formerly Steel Structures Painting Council)
1.03 PROJECT/SITE CONDITIONS
- Environmental Requirements: Do not apply finish material when temperature is below 50 degrees F. and falling. Do not apply paint on surfaces in direct sunlight. Do not apply finishes in spaces where dust is being generated, which would speck the finish.
- Benjamin Moore
01 Paragon Drive
Montvale NJ 07645
- Martin Senour
- ITW Devcon, Inc.
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 (*).
- Mineral spirits
- QA 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.
- Emery paper
- Flint sandpaper
- Fine steel wool
- 600 grit aluminum oxide
- Rust remover solution containing orthophosphoric acid. Several are available in gel form from retail outlets.
- Soft rags
- Clean, potable water
- Sealant: Polysulfide sealant, color as approved by RHPO.
- Metal Filler: Steel filled two part epoxy metal filler, putty grade, such as "Plastic Steel 5 Minute Putty (SF)" (Devcon Corporation), or approved equal.
- Paint for Metal Paint and Finish Products, such as those by Benjamin Moore, Sherwin Williams, Martin Senour, or approved equal. See also 05010-13-S for general information on the advantages and limitations of various paint and primer types.
- 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 the highest quality of an approved manufacturer.
- Colors: Primer coats to be clearly different in color from each other; base coat to be clearly different from primer or finish coat; finish coat to be approved by RHPO.
- Dry Film Thickness: Each coat to be 2 mils.
- Rubber gloves
- Eye and skin protection
- Paint scrappers and putty knives
- Ball peen hammer
- Sanding blocks, sanding sponges, sanding wheels
- Wire brushes
- Stiff natural bristle brushes
- Rotary wire wheels
- Proper, heavy-duty extension cords
- Air-abrasive cleaning equipment (80-100 psi) for use with fine grit dry and wet abrasives. Consult RHPO.
- Water hose
- Before work is begun on removing the existing paint film or otherwise preparing the surface all sources of excess moisture shall be determined and repaired as required.
- Execute test samples of the cleaning methods specified in this procedure to determine which method(s) are to be used. Sample areas shall be selected by the RHPO and shall include at least one ornamental area and one flat area, or as necessary to include all surface types likely to be encountered in this work.
- Method(s) used in the actual cleaning shall be the one(s)which provide the necessary level of cleanliness with the least amount of surface alteration. Final selection of methods shall be made by the RHPO.
- Protect adjacent surfaces, including grass, shrubs and trees with paper, drop cloths and other means. Items not to be painted which are in contact with or adjacent to painted surfaces shall be removed or protected prior to surface preparation and painting operations. All methods of enclosure and protection should be approved by the supervisor.
- Work area shall be sealed to prevent the spread of dust, debris and water beyond the work site, and to assist in the collection of contaminants.
- Provide protection boards to vulnerable decorative work and maintain for the duration of operations.
- All waste material shall be collected at the end of each work day and properly disposed of. It is considered Hazardous Waste.
- After each days paint removal work is complete, area shall be vacuumed with machines equipped with HEPA (High Efficiency Particulate Air) filters to insure all lead dust has been removed.
- Surface Preparation: Determine surfaces to which painting and finishing are to be applied are even, smooth, sound, clean, dry and free from defects affecting proper application. Correct or report defective surfaces to Contracting Officer.
3.03 ERECTION, INSTALLATION, APPLICATION
- Metal Cleaning, General
NOTE: Remove only as much paint and rust each day as can be primed that same day. Bare iron and steel will begin to rust again within a matter of hours. It should not be allowed to site unportected overnight.
- Remove all paint and scale from all surfaces to bare metal.
- Dismantle iron lamp standards.
- Mechanical/Abrasive Rust/Paint Removal: OBTAIN RHPO
APPROVAL BEFORE PROCEEDING WITH WORK.
- To determine the degree of deterioration and the level of paint removal required, clear away all dust and debris followed by rub-down with mineral spirits.
- To remove light rust and flaking, peeling paint:
- Begin with emery paper or aluminum oxide sandpaper.
- Use scrapers to get under loose paint and into crevices.
- Use a wire brush, or an electric drill with a special wire brush or rotary sandpaper whip attachment if above two methods do not remove paint.
- Air-abrasive Paint Removal: OBTAIN RHPO APPROVAL BEFORE PROCEEDING WITH WORK.
- NOTE: While air abrasive cleaning (commonly known as sandblasting) is destructive for softer building materials, iron, a hard material with a natural uneven surface, will not be noticeably damaged by its careful use.
- CAUTION: Do not use air-abrasive cleaning methods in the following situations:
- On thin sections or fine,intricate details of wrought iron features.
- On zinc and galvanized iron and steel.
- On features for which the original surface texture is an integral part of the design (air-abrasive cleaning will alter original surface texture and appearance).
- On stainless steel features.
- Air pressures at the compressor shall be between 40 psi to 70 psi.
- Grit size shall be in the range of #10 to #45, i.e. copper slag. Other abrasives, such as ground walnut shells, or other abrasive methods such a glass bead peening, may also be appropriate but should be performed only under the direction of an architectural conservator and/or the RHPO.
- A pencil-point nozzle shall be used to allow more complete control. Nozzle shall allow for independent control over air, water and abrasive and should be held no closer than 12" from the surface to be cleaned.
- Flush all surfaces with water to remove all traces of slurry and spent abrasive. Final rinse shall contain rust inhibitor with no more than 5000 ppm.
CAUTION: Larger concentrations of rust inhibitor will result in the deposition of salts on the metal surfaces which will cause the paint to peel.
- Dry surfaces immediately, especially any horizontal surfaces or water traps which might collect water.
- Prime as soon as possible after surfaces have been dried but before rust has a chance to reform. See 05010-13-S for general information describing paints and primers for cast-iron. Apply second prime coat after first has dried completely. Secure approval of surface preparation andeach coat prior to proceeding with the next.
- Re-assemble cast iron lamp standards. Seal all open joints between metal elements and metal and masonry with polyethylene backer rods and polysulfide sealant. Joint shall be concave with smooth finish.
- Fill all holes, depressions and cracks with metal filler and sand to conform with surrounding contours. See 05010-12-R for guidance.
- Prime and paint all surfaces. Brush apply two finish coats of paint.
- Apply material evenly without runs, sags, or other defects. Work each coat onto the material being coated at an average rate of coverage recommended. Cover surfaces complete to provide uniform color and appearance with a minimum of dry film thickness of 2 mils. Make edges of paint adjoining other materials or colors sharp and clean, and without overlaps.
- Drying time: Minimum time as recommended. Do not apply succeeding coats until the undercoat is thoroughly dry.
- For guidance see 05010-13-S “Primers and Paints for Wrought Iron, Cast Iron and Steel,” 05010-18-R “Applying a Sacrificial Coating to Wrought Iron, Cast Iron and Steel,” and 09900-07-S “General Guidelines for Painting Exterior and Interior Surfaces.”
- Cleanup: Remove all paint where it has spilled or spattered. Do not drip any paint on stone. No chemical cleaners allowed.
- Protect cleaned or final finishes from damage during building or project cleaning period by use of temporary protective coverings approved by RHPO. Remove protective covering at time of Substantial Completion.