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 cleaning exterior polished and honed granite.
- Safety Precautions:
- The work specified herein requires knowledge of older materials and methods and a high degree of skill to execute properly. This work should be performed only by an experienced, pre-qualified contractor. It is not recommended that building maintenance personnel perform this work. 2. This outline specification contains recommended materials which may be toxic. The manufacturer s literature on application techniques, appropriate protection for workers and disposal procedures for materials should be complied with in conjunction with all regulatory requirements referenced in this document.
- 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).
- Product Data:
- Submit manufacturer's technical data for each product indicated including recommendations for their application and use to the Contracting Officer or the designated representative. Include test reports and certifications substantiating that products comply with requirements.
- Prior to commencing the cleaning operations, submit to the Contracting Officer or the designated representative a written description of the materials, methods, and equipment proposed for cleaning each type of masonry included in the work of this section including, but not limited to: cleaning products and chemical components, method of application, dilution of application, temperature of application, length of time of surface contact, method of rinsing surface (temperature, pressure, and duration), repetition of procedures, etc.
- Protection Program: Prior to commencing the cleaning operations, the Contractor shall submit to the Contracting Officer or the designated representative for approval, a written description of proposed materials and methods of protection for preventing damage to adjacent materials, vehicular and pedestrian traffic, and the building interior during the cleaning of stone.
- Prior to the start of masonry cleaning, prepare for approval a sample panel, approximately 3 x 3 feetin area, on each type of masonry included in the work where directed by the Contracting Officer or the designated representative.
- Adjust the chemical concentrations, working pressures and methodologies during test panel cleaning, as directed by the Contracting Officer s representative.
- Clean sample panels using methods, materials, and working pressures previously submitted and approved. Perform sample panel cleaning in the presence of the Contracting Officer or the designated representative
- Where chemical cleaners and poultices are tested, perform testing in the presence of the manufacturer's representative.
- Obtain written approval from the Contracting Officer or the designated representative of cleaning methods, working pressures, materials, equipment used and sample panels before proceeding with building cleaning operations. Allow a minimum of seven calendar days after completion of sample cleaning to permit study of sample panels for negative reactions. Retain approved panels in unaltered condition, suitably designated during construction as a standard for judging completed work.
1.03 QUALITY ASSURANCE
- The objective of stone cleaning is to remove soiling, stains and crusts from the granite without damaging underlying material and to give all stone a clean, uniform appearance without blotches, streaks, or other irregularities. Use the gentlest means to meet the cleaning objective.
- Cleaning Standard: Prepare sample panels for approval which shall establish a standard for general stone and brick cleaning. Cleaning shall not commence until written approval is obtained for sample panels and submittals from the Contracting Officer or the designated representative.
- Regulatory Requirements: Comply with municipal and Federal regulations governing the cleaning, chemical waste disposal, scaffolding protection to adjacent properties and workers.
1.04 PROJECT/SITE CONDITIONS
- Environmental Requirements:
- No cleaning shall be executed when air or masonry surface temperature is below 45 degrees F, unless adequate, approved means are provided for maintaining a 45 degrees F, temperature of the air and materials during, and for 48 hours subsequent to, cleaning.
- Perform cleaning and rinsing of the exterior masonry only during daylight hours.
- Detergent: Commercially available surface active liquid cleansing agent specifically formulated for cleaning masonry, such as "Ion 417" (Chemique Inc.), or approved equal.
- Liquid Strippable Masking Agent: Manufacturer's standard liquid, film forming, strippable masking material for protecting glass, metal and polished stone surfaces from damaging effect of acidic and alkaline masonry cleaners, such as "Sure Klean Strippable Masking" (ProSoCo, Inc.), "Diedrich Acid Guard" (Diedrich Technologies, Inc.), or approved equal.
- Water: Potable, non-staining and free of oils, acids, alkalis and organic matter.
- Brushes: Natural fiber bristle only. The use of wire brushes or steel wool is not permitted.
- Garden hose with fan tip nozzles
- Take all necessary precautions and measures to protect surrounding materials on the site, surfaces of the building not being cleaned, adjacent buildings, pedestrians and vehicles from coming in contact with cleaning chemicals, over spray, or runoff. Products used for masonry cleaning may be harmful to painted, polished, glazed, or metallic surfaces. Any damage to materials caused by the cleaning operations is unacceptable and shall be repaired or replaced by the Contractor to the satisfaction of the Contracting Officer or the designated representative at no cost to the Government.
- Provide protection from water damage to building, structure, or building contents as required.
- Protect trees and plants around the building from contamination or damage. The Contractor shall be responsible for replacing with new stock, any trees, shrubbery or grass damaged by the cleaning operations.
- Test all drains and other water removal systems to assure that drains and systems are functioning properly prior to performing any cleaning operations. Notify Contracting Officer or the designated representative immediately of any and all drains or systems that are found to be stopped or blocked. Contractor shall repair drains if so directed by the Contracting Officer or the designated representative. Do not begin work of this Section until the drains are in working order.
- Provide a method to prevent solids such as stone or mortar residue from entering the drains or drain lines. Contractor shall be responsible for cleaning out drains and drain lines that become blocked or filled by sand or other solids because of work performed under this Contract.
3.02 ERECTION, INSTALLATION, APPLICATION
- Dilute detergent with 3 parts water to 1 part concentrate, or use appropriate dilution as determined by field testing.
- Brush apply to granite, scrub for 10 minutes with stiff bristle brushes.
- Rinse the treated area thoroughly using pressurized cold water, not exceeding 300 psi, sprayed through nozzles fitted with 15 to 20" wide tips. Nozzles shall be held perpendicular to the surface at a working distance of 1.4 to 2.0 feet. All pressure pumps shall be equipped with working pressure gauges. D. Rinse from the bottom of the treated area to the top flushing each section of the surface with a concentrated stream of water. To avoid streaking on vertical walls, take care to keep the wall below wet and rinsed free of cleaner and residues.
- The surfaces below the sections of brick to be cleaned shall be protected from run-off.
- Repeat procedures if necessary to remove heavier build-up of soiling.