U.S. General Services Administration
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.
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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.
PART 1–GENERAL
1.01 SUMMARY
A. This procedure includes guidance on mild cleaning of interior Mankato stone surfaces such as baseboards, wainscoting, pilasters, door surrounds and cornices.
B. Mankato stone is also known as Yellow Kasota or Floridene Marble.
C. Yellow Vein Kasota Marble is warm to pale yellow in appearance and slightly streaked with thin dark markings.
D. Yellow Fleuri Kasota Marble is warm yellow and mottled by paler yellow.
PART 2–PRODUCTS
2.01 MATERIALS
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 (*).
A. Sodium Tripolyphosphate:
- A crystalline salt (NA5P2010) used chiefly as a builder in soaps and detergents, as a sequestering agent and as a deflocculating agent.
- Other chemical or common names include Penta-sodium Triphosphate.
- Available from chemical supply house.
- Used in the making of general cleansers, dishwashing liquids or laundry detergent; It is a chemical responsible for increasing the sudsing action in cleaners. Depending on the amount added, it also conditions water, facilitates rinsing, aids in dispersion of soil and removes soap film from previous washings.
B. Clean, Potable Water
2.02 EQUIPMENT
A. Sponges
B. Chamois
C. Natural Bristle Brushes
D. Clean, Soft Cloths
PART 3–EXECUTION
3.01 PREPARATION
A. Protection: Protect all masonry and metal surfaces immediately adjacent to or below the area to be cleaned
3.02 ERECTION, INSTALLATION, APPLICATION
A. Mix 5% sodium tripolyphosphate solution using warm water.
B. Apply the cleaning solution to the standing stone with a soft natural bristle brush working from the bottom of the wall up. Wash in small overlapping areas.
C. Rinse each cleaned area thoroughly with fresh clear water using sponges to remove traces of cleaner. Use clean chamois or clean soft cloths to dry and buff the surface and prevent streaking.