Specification:Removal and replacement of limewash

__NUMBEREDHEADINGS__ =GENERAL=

DESCRIPTION
 This specification provides procedures appropriate for removing, preparing and applying limewash. This specification has been developed for use on historic properties (defined as any district, site, building, structure, or object that is listed or eligible for listing in the National Register of Historic Places) and provides an overview of accepted practices. All work described herein and related work must conform to the Secretary of Interior’s Standards for the Treatment of Historic Properties. The Contractor shall provide all labor, materials, equipment, and operations required to complete the rehabilitation work indicated herein. All work described herein and related work must have the approval of a Cultural Resources Manager, Conservator Historic Architect or other professional that meets the standards outlines in the Secretary of Interior’s Standards – Professional Qualifications Standards pursuant to 36 CFR 61. Such a person is referred to in the document as the Architect. The Architect will provide site-specific specifications, when appropriate.  

SECTION INCLUDES
 Removal of deteriorated limewash</li> Preparation/Application of limewash</li> </ol>

RELATED SECTIONS
<ol type="A"> 04100 – Historic Mortar</li> 04110 – Historic Stucco</li> 04211 – Historic Brick</li> 04400 – Stone</li> 04510 – Masonry Cleaning</li> 09910 – Surface Preparation and Repainting of Paint on Masonry</li> </ol>

Definitions
<ol type="A"> Carbonate (Carbonation): Limewash reacts with carbon dioxide in the air, resulting in the release of water and conversion of the limewash (calcium hydroxide) to the parent material (calcium carbonate).</li> Cleaning Test Patch: A small unobtrusive area, usually less than six inches by six inches, in which the contractor tests a particular cleaning method. Several cleaning test patches are usually performed side by side to directly compare methods.</li> Hydrated Lime: A calcium hydroxide powder formed when quicklime is slaked with the minimum amount of water needed to create a workable material.</li> Lime Putty: Material created when quicklime is slaked with an excess of water.</li> Limewash: Traditional finish consisting of lime and water with or without additional additives. A few of the common additives were tallow, casein, or pigment that was necessary to create a colorwash. Limewash is built up through multiple layers applied over several days to allow for individual layers to carbonate.</li> Slaking: Process of adding water to quicklime to create a workable material.</li> Quicklime: Material remaining after calcium carbonate (commonly limestone or shell) is heated in a kiln releasing carbon dioxide and forming calcium oxide. Caustic material that must have water added to be used in construction. </li> </ol>

SUBMITTALS
<ol type="A"> Submit a detailed schedule to Architect for approval of work under this section, including assessment of the problem areas, historic limewash analysis, and detailed procedures for limewash removal and replacement.</li> Product Literature: Submit manufacturer’s product literature to Architect for all manufactured products specified for removal of limewash and for preparation of new limewash. Product literature shall include specification data, Material Safety Data Sheets and instructions for storage, handling and use.</li> <li>Samples: The Contractor shall submit samples of the following limewash materials for approval of color and texture match. No work shall proceed until all samples are approved. Cured limewash samples: Prepare portable samples approximately six inches by six inches. Samples are to be prepared on a substrate similar to that to receive the final application. Once a matching limewash color is achieved, placement of on-site mock-ups may begin.</li> </ol>

QUALITY ASSURANCE
<ol type="A"> <li>Work Experience: The selected Contractor shall have demonstrated experience with historic limewashes, stucco and plaster, ideally a minimum of seven years. The Contractor shall demonstrate a working knowledge of The Secretary of the Interior's Standards for the Treatment of Historic Properties with Guidelines for Preserving, Rehabilitating, Restoring &amp; Reconstructing Historic Buildings.</li> <li>The Contractor shall not change sources or manufacturers of limewash materials during the course of the work.</li> </ol>

MOCK-UPS
<ol type="A"> <li>After selection of a limewash color(s) from the portable samples, the Contractor shall prepare two mock-up installations of each type of limewash to be installed at locations selected by the Architect. If cleaning tests are also to take place, test panels should be in the same area. Test panels should be undertaken in areas that are not highly visible. Each test panel shall be executed in the same manner as the final installation. Test panels shall be a minimum area three feet by three 3 feet. Test panels will be inspected for color and installation technique.</li> <li>The Contractor shall prepare up to three additional mock-ups of each limewash color at no additional cost to the Owner. </li> </ol>

DELIVERY, STORAGE AND HANDLING
<ol type="A"> <li>Deliver all manufactured products to the site in original packaging, unopened and undamaged, with manufacturer’s name and product identification visible thereon, manufacturer’s instructions and Material Safety Data Sheets.</li> <li>Store products in a dry location and protected from dampness and freezing following manufacturer’s instructions.</li> </ol>

PROJECT / SITE CONDITIONS
<ol type="A"> <li>Normal conditions for the work of this Section shall be defined as when the air and surface temperatures are 40 degrees F and rising or less than 80 degrees F and falling, unless otherwise permitted by the Architect. Limewash is ideally applied between the temperatures noted above. </li> <li>Work shall not commence when rain, snow or below-freezing temperatures are expected within the next 24 hours. Relative humidity should not exceed 85 percent. All surfaces shall be free of standing water, frost, and ice.</li> <li>Do not apply limewash in direct sunlight when ambient temperatures exceed 80 degrees F. Measures should be taken to screen sunlight from the limewash application by working following the sun or installing temporary artificial methods to shield surface work. Dampened burlap can be hung near the application, but not touching the limewash, to lower temperatures of surface during drying. Misting the surface lightly can also help slow drying if temperatures are too high.</li> <li>The contractor is responsible for protecting existing adjacent material surfaces, and substrate during the execution of the work. Provide all necessary protection and work procedures to avoid damage to existing material assemblies not a part of the work in the Section.</li> <li>When limewash mix is applied in poor or unfavorable weather conditions the finish may “flash dry” leading to a poor coating that powders or flakes from the substrate or underlying coats. This condition will not be accepted and may require removal of the applied coat.</li> <li>Provide visible barriers and/or warning tape around the perimeter of the work area for visitor protection. Protect nearby vehicles and adjacent structures from damage during the course of the work.</li> <li>The Contractor shall coordinate limewash work with the other trades involved in exterior and interior restoration work including, but not limited to, masonry cleaning and restoration, sealants, and painting.</li> </ol> =PRODUCTS=

REMOVAL OF DETERIORATED LIMEWASH
<ol type="A"> <li>Materials <ol> <li>Water: Clean and potable.</li> </ol> </li> <li>Equipment <ol> <li>Plastic sheets to cover poultice</li> <li>Wood or plastic spatula</li> <li>Phosphor bronze or stiff, natural bristle brushes</li> </ol> </li> </ol>

MATERIALS FOR LIMEWASH
<ol type="A"> <li>Sources of Lime Putty: <ol> <li>Job-Mixed Lime Putty: Hydrated lime Type S or Type N (high calcium). Slake quicklime in approximate ratio of eight gallons of water to 38 pounds quicklime. Follow manufacturer’s instructions and all safety precautions. Age slaked quicklime for at least 90 days. Sieve through a fine screen to remove grit and impurities. </li> <li>Manufactured Lime putty: Pre-mixed, non-hydraulic lime putty can be purchased from an approved manufacturer or an Architect approved equal.</li> </ol> </li> <li>Water: Clean water free from impurities and contaminants.</li> <li>Pigment: Pigment for colored limewashes shall be alkali-resistant, non-fading, mineral oxide masonry pigment, Architect approved and not to exceed 10 percent of lime weight. Lime-safe pigments, usually earth based materials, are necessary to protect against fading or color change. </li> <li>Preparations of Limewash: Limewash is generally 15 to 20 percent lime and 80 to 85 percent water to the consistency of whole milk. <ol> <li>Limewash from lime putty (20:80) 24 gallons water Six gallons (42 pounds) lime putty</li> <li> Thin Limewash from lime putty (15:85) 34 gallons water Six gallons (42 pounds) lime putty</li> <li>Limewash from hydrated lime (20:80) Seven gallons water 50 pounds hydrated lime</li> <li>Thin limewash from hydrated lime (15:85) Seven and one-half gallons water 50 pounds hydrated lime</li> </ol> </li> </ol>

PRE-MIXED LIMEWASH
<ol type="A"> <li> Pre-mixed limewashes may be substituted for job-mixed limewashes at the Contractor’s option contingent upon approval of submitted product data.</li> <li>ACCEPTABLE MANUFACTURERS: Unless noted otherwise, products from an approved manufacturer or an Architect approved equal.</li> </ol>

EQUIPMENT FOR MIX AND APPLICATION OF LIMEWASH
<ol type="A"> <li>Drill with long-stem paddle mixer</li> <li>Large clean plastic can (such as a 32 gallon garbage can)</li> <li>Plastic pails</li> <li>Medium stiff natural bristle brushes: limewash brush or a large brush similar to that used to apply wallpaper paste.</li> <li>Spray equipment (optional method)</li> </ol> =EXECUTION=

GENERAL
<ol type="A"> <li>All masonry repair work shall be completed prior to application of limewash.</li> <li>The Contractor shall protect adjacent materials, and openings, and substrate. </li> <li>Follow manufacturer’s instructions and appropriate safety precautions.</li> </ol>

REMOVAL OF DETERIORATED LIMEWASH
<ol type="A"> <li>Protection: Provide adequate water, soap and towels for washing prior to start of work.</li> <li> Removal of Deteriorated Limewash <ol> <li>Dampen down the walls, preferably over several days, to loosen the deteriorated limewash. When the limewash begins to loosen scrub with a stiff natural bristle or soft nylon bristle brush to remove limewash. </li> <li>Limewash will still be visible in indentations along the surface and may be attached in areas where it has not deteriorated. It is difficult to remove all traces of limewash without damaging the surface material. </li> </ol> </li> <li>Application of Poultice (if needed, determined by the Architect): <ol> <li>Not recommended for large areas.</li> <li>Mix attapulgite or sepiolite clay with water to form a thick paste.</li> <li>Thoroughly wet the area to be treated with clean water.</li> <li>Apply poultice to the limewash with a wood or plastic spatula and cover with plastic.</li> <li>When poultice is dry, remove with a wood scraper.</li> </ol> </li> <li>Rinse the surface thoroughly with clean water and allow to dry. Process may be repeated if necessary. </li> </ol>

PREPARATION FOR LIMEWASH
<ol type="A"> <li>Complete any required masonry repairs prior to applying limewash.</li> <li>Surface shall be clean and free from grease and dirt. <ol> <li>Biological growth may be cleaned with an approved biocidal cleaner. Thoroughly wash with clean water prior to application of limewash. Do NOT use cleaners that contain silicon.</li> <li>Scrape or brush away any loose limewash.</li> </ol> </li> </ol>

APPLICATION OF LIMEWASH
<ol type="A"> <li>Prepare limewash, combining lime putty and water to a milk-like consistency. When using colored limewash, order and mix the entire amount plus 15 percent to ensure even color. Mix thoroughly so that the lime is fully suspended in mixture. When transferring limewash to smaller pails, mix to ensure even consistency.</li> <li>Dampen surface by spraying with water from a hand sprayer until the surface glistens, but there is no standing water. Dampen an area approximately 10 square feet or greater at a time. Do NOT apply limewash to a dry surface.</li> <li>Apply in thin translucent coats with a limewash or similar brush. Do NOT over apply; thick coats will become crazed. Work limewash well into the surface, including mortar joints where applicable. </li> <li>Generally five coats or greater are required on the initial application. Allow limewash to dry between coats, generally 12 to 24 hours. Re-wet the previous coat before applying the next coat.</li> </ol>

FINAL REPORT
<ol type="A"> <li>Provide a final report of complete work including all approved submittals and photographs of the repaired areas taken before, during and after the work. </li> </ol>