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.
Paint Removal and Repainting Sheet Iron, Steel and Tin-Plated Ceilings
Projects involving paint removal are subject to state and federal laws on lead paint abatement, disposal and use of volatile organic compounds (VOCs). Specified products may not be permitted or appropriate for all locations. Products containing chemicals known to present health or environmental hazards should be used only as a last resort, where permissible, in accordance with manufacturer's directions and government requirements. Test milder formulations for effectiveness before proceeding to stronger alternatives.
- This procedure includes guidance on chemically removing paint from and painting sheet iron, steel and tin-plated ceilings.
- Metal ceilings can be made from either sheet iron or steel, or tinned steel. Older ceilings are most likely sheet iron of copper or of the white metals popular in the 1920s and 1930s (such as nickel silver and Monel) were usually left unpainted and as a result will not be discussed here.
- One of the main reasons for paint failure is moisture. Before work is begun on removing the existing paint film or otherwise preparing the surface all sources of excess moisture shall be determined and repairs completed as required.
- An archive of the paint history of the building is to be maintained. This is to include any paint samples taken during research, samples of the new paint colors and the manufacturer's technical information.
- Safety Precautions:
- Paint being removed most likely will contain lead. All workers must wear protective clothing (including hair), goggles and respirators with proper filters.
- No food or drink shall be allowed near any work station so as to prevent contamination from paint, paint chips, dust or chemical removers which contain lead and other toxic substances.
- Protective clothing shall be removed at the end of each day and kept at the site to prevent workers from tracking dust and paint chips to other parts of the site or to their homes.
- Wash hands and face often, especially before eating and at the end of the day.
- All waste material shall be collected at the end of each work day and disposed of in a manner consistent with local environmental regulations. It is considered Hazardous Waste.
- 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:
- Safety Precautions
- Historic Structures Precautions
- Quality Assurance
- Delivery, Storage and Handling
- Project/Site Conditions
- Sequencing and Scheduling
- General Protection (Surface and Surrounding)
1.02 SYSTEM DESCRIPTION
- The primary purpose of paint is to protect the metal from deterioration. To do so, paint manufacturers have developed paint systems which are made to work together to protect the metal substrate. These systems include primers and appropriate, compatible top coats which can vary depending on the substrate and can vary between manufacturers. As a result appropriate primers and compatible top coats, both from the same manufacturer should be used.
- A paint film is in good condition when it is clean and free of any peeling, cracking or rusted areas and when it retains its color and gloss.
- For Chemical Paint Removers:
- Savogran Company
- Recochem, Inc.
Montreal, Quebec H4T 1P4
1-800-361-6030 (U.S. location) or
514-341-3550 (corporate headquarters)
- W. M. Barr & Co.
- For Fumed Silica:
- Evonik (Aerosil)
- Cabot Corporation (Cab-o-sil)
- Dow Corning (Wacker Chemie)
- OCI (Konasil)
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 (*).
- Semi-paste, water rinsing, nonbenzol chemical paint remover such as "Strypeeze Semi-Paste" (Savogran Company), or a methylene chloride-free alternative such as "Citristrip Stripping Gel" or "Citristrip Aerosol Paint and Varnish Remover" (W. M. Barr & Co.), or approved equivalent.
- Available from hardware store and paint store.
- Characteristic orange color.
- Will work on latex and oil-based paints, lacquers and varnishes.
- Cling well to round or vertical surfaces.
- Form an anti-evaporative film as they dry.
- Clean-up by either washing or scraping off.
- All traces must be removed and a neutral pH achieved before repainting.
- Non-flammable, heavy bodied methylene chloride-based paint removers such as "Zip-Strip" (Recochem, Inc.) or approved equal:
- Available from hardware store or paint store.
- Good for interior use because they are non-flammable.
- Will soften oil-based paints, lacquers, varnish and synthetic baked finishes.
- Will cling well to vertical and irregular surfaces.
- NOTE: Contains methylene chloride, a known carcinogen. Methylene chloride is banned in some states such as California. Regulatory information as well as alternative or equivalent chemicals may be requested from the Environmental Protection Agency (EPA) Regional Office and/or the State Office of Environmental Quality.
- Cornstarch or fumed silica* to thicken chemicals so they will adhere to ceilings.
- 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.
- Denatured Alcohol:
- Other chemical or common names include Methylated spirit*.
- Potential hazards: TOXIC AND FLAMMABLE.
- Available from hardware store, paint store or printer's supply distributor.
- Denatured alcohol should be a satisfactory substitute for ethyl alcohol for stain removing purposes.
- Used to test pH of a surface after stripping with chemicals or any alkaline product.
- Available from chemical supply house or drug store.
- Chemical rust remover such as Naval Jelly.
CAUTION: DO NOT USE HYDROCHLORIC ACID-BASED PRODUCTS.
- Zinc-rich oil-based primer such as zinc chromate or red iron oxide-linseed oil paint:
- Good for use on partially deteriorated surfaces such as old ceilings.
- Provides protection where moderately corrosive conditions exist.
- Modern alkyd paint:
- Should only be applied to clean, non-corroded surfaces.
- Provides protection where there are only mildly corrosive conditions, and where normal humidity and condensation ranges exist, i.e. a residential or office environment.
- NOTE: Consult the paint manufacturer for appropriate choice for use on metal.
- Oil-based Top Coats:
- Any oil-based top coat, made to be used with the primer, may be applied as the top coats.
- Use paint from the same manufacturer for both prime and top coats, and make sure they are made to work together.
- Latex caulk.
- Plastic sheeting.
- Clean, potable water.
- Wire brushes (various sizes and shapes).
- Duct tape.
- Steel wool, scrapers and small picks to remove sludge.
- Metal containers such as old coffee cans to dispose of sludge.
- Natural bristle paint brushes.
NOTE: Condition new brushes by soaking in raw linseed oil for 24 hours before using.
- Work area shall be sealed to prevent the spread of paint dust and debris beyond the work site.
- After paint removal is complete, all areas around the site shall be cleaned of all paint dust and debris, and such debris shall be properly disposed of in a manner consistent with local environmental regulations.
- Protect adjacent surfaces 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.
3.02 ERECTION, INSTALLATION AND APPLICATION
- Remove all loose paint and rust with wire brushes.
- Remove remaining paint using the thickest chemical paint remover available. Add cornstarch to thicken it further so that it will cling to the ceiling surface. Work in small areas at a time to provide maximum control over dwell time and removal.
- Cover with plastic and allow to remain on the ceiling as per manufacturer's instructions. Remove sludge with scrapers.
- Rinse thoroughly with mineral spirits and fine steel wool.
- If areas of rust still remain, use a chemical rust remover to remove the last traces, or as much of the rust as is possible.
- After removal has been completed, rub all surfaces down with mineral spirits to remove all traces of dust and chemical residue.
- To test whether all chemicals have been removed dissolve a 2" piece of phenolphthalein in denatured alcohol.
- Brush the solution onto the surface. If it turns a shade from pink to magenta there is still chemical residue.
- Treat the surface with additional mineral spirits and continue testing until there is no color change in the phenolphthalein solution.
- Prime immediately to prevent rust and paint. Use a brush for complete, even coverage.
- Fill any open joints with a paintable latex caulk.
- Use a brush to apply two top coats of the selected paints to insure adequate protection of the metal.
NOTE: DO NOT USE LATEX-BASED PAINTS BECAUSE THE WATER VEHICLE WILL CAUSE THE METAL TO RUST.