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 removing iodine stains from terrazzo floors.
- Iodine is a nonmetallic element used especially in medicine, photography and analysis.
- 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).
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 (*).
- Rubbing* or Isopropyl Alcohol (C3H8O):
- A volatile flammable alcohol used especially as a solvent and rubbing alcohol.
- Other chemical or common names include Dimethyl carbinol; Isopropanol; 2-propanol.
- Available from chemical supply house, dry cleaning supply distributor, drug store, hardware store, paint store or printer's supply distributor.
- B. Whiting:
CAUTION: DO NOT USE WHITING WITH ACID (SUCH AS IN A POULTICE), AS WHITING IS A CARBONATE AND REACTS WITH ACID TO PRODUCE CARBON DIOXIDE. THIS REACTION IS NOT DANGEROUS; HOWEVER, THE COMBINATION RENDERS THE ACID INEFFECTIVE AND PRODUCES A FOAMY MESS.
- Other chemical or common names include Powdered chalk. Kitchen flour may also be substituted.
- Available from paint store.
Talcum Powder: Available from drugstore or pharmaceutical supply distributor.
- Wooden Paddle or Trowel
- Shallow Enameled Pan
- Examine the terrazzo surface carefully to determine the cause of staining. Eliminate cause before proceeding with any cleaning operation.
3.02 ERECTION, INSTALLATION, APPLICATION
NOTE: THE FOLLOWING TREATMENTS SHOULD BE USED BY TRAINED AND EXPERIENCED PERSONNEL. IMPROPER USE MAY RESULT IN BLEACHING THE TERRAZZO MATRIX IF A COLOR DYE WAS ADDED AT THE TIME OF INSTALLATION.
- An iodine stain will gradually disappear without treatment.
- For quick removal, apply alcohol and cover it with whiting or talcum powder.
- If the stain occurs on a vertical surface, talcum should be mixed with alcohol to form a paste. Alcohol is first applied to the stain, and it is then covered with the paste.
- Remove dried paste with wooden spatula.
- Rinse thoroughly with clean, clear water and repeat the process as required until stain is no longer noticeable.