General Project Guidelines

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.


PREFACE: This standard includes general project guidelines provided to supplement specific repair and preventive maintenance procedures. Not all of these requirements will be applicable given the level of difficulty of the procedure. However, where applicable, these guidelines should be used in addition to recommendations provided by the regional historic preservation officer (RHPO). The information is listed in the order it might appear in the usual CSI section format.

  1. The supervisor should ensure that all workers wear adequate, approved protective clothing and are provided with protective equipment during work operations and as required at other times.
  2. Check manufacturer's literature for precautions and effects of products and procedures on adjacent building materials, components, and especially vegetation. Take appropriate protective measures.
  3. All workers must be protected from the effects of chemicals during repair or cleaning operations.
    1. DO NOT save unused portions of stain-removal materials.
    2. DO NOT store any chemicals in unmarked containers.
    4. No use of organic solvents indoors should be allowed without substantial air movement. Use only spark-proof fans near operations involving flammable liquids.
    5. Provide adequate clothing and protective gear where the chemicals are indicated to be dangerous.
    6. Have available antidote and accident treatment chemicals where noted.
    7. Avoid skin contact and inhalation of any chemical. Rubber or plastic gloves should be worn when handling hazardous (flammable or toxic) chemicals.
      1. Follow storage and handling procedures printed on the container labels of the cleaning solutions, provide good ventilation while working, and thoroughly wash hands after completion of the work.
      2. Provide protective clothing which must be worn and protective creams for exposed skin areas.
      3. Accidental contact with unprotected skin to these materials must be treated immediately by washing with soap and water, never with solvents.
      4. Exercise care to avoid skin contact to tool cleaning solvents and to provide adequate ventilation for clean-up operations.
  4. When removing bird droppings: Bird droppings may expose workers to the effects of cryptococcosis and histoplasmosis which endanger the human respiratory system. Public health authorities should be consulted for appropriate precautions.
    1. All contractor personnel must wear a National Institute for Occupational Safety and Health (NIOSH) approved full face respirator with a high efficiency particulate air (HEPA) filter for screening particles of 0.3 micron size. Dust and particle masks are not appropriate.
    2. Respirators must be used in accordance with OSHA regulation, 29 CFR 1910.134 and GSA policy, PBS P 5900.2C, Chapter 3, section 8. This includes fit-testing of respirators, maintenance, training, and storage requirements.
    3. All contractor personnel must wear protective coveralls, gloves, boots, and hats.
    4. Prior to removal, all excrement must be saturated with water under low pressure to prevent debris from becoming airborne.
    5. On historic structures, only non-metallic tools (such as plastic spatulas and brushes with natural fiber or nylon bristles, or their equivalent) must be used to remove the excrement.
    6. Removed excrement must be collected in plastic bags, sealed, and disposed of by the contractor at a sanitary landfill.
    7. All work must be performed from the outside of the building. Building occupants and the general public must be kept clear of the work site during all operations. It is the contractor's responsibility to provide all barricades, signage, etc. necessary for public protection.
  5. When removing paint:
    1. Paint being removed most likely will contain lead. All workers must wear protective clothing (including hair), goggles and respirators with proper filters.
    2. 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.
    3. Protective clothing shall be removed at the end of each day and kept at the site to prevent workers from trackingdust and paint chips to other parts of the site or to their homes.
    4. Wash hands and face often, especially before eating and at the end of the day.
    5. 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.


  1. The principal aim of any work must be to halt the process of deterioration and stabilize the item's condition. Repair is a second option which becomes necessary only where preservation is not sufficient to ensure mid- to long-term survival. Repair should always be based on the fundamental principle of 'minimal disturbance'. The following are good practices which arise from this principle:
    1. Retention of as much existing material as possible; repairing and consolidating rather than renewing.
    2. The use of additional material or structure to reinforce, strengthen, prop, tie, and/or support existing material or structure.
    3. The use of reversible processes wherever possible.
    4. The use of traditional materials and techniques. New work should be distinguishable to the trained eye, on close inspection, from the old.
    5. The item should be recorded before, during and after the work.
      1. No smoking will be allowed by personnel performing work on or about Historic Structures.
      2. RHPO's approval is required for any change, addition or removal of historic structural fabric or historic property.
      3. RHPO should be notified of any visible change in the integrity of the material or component whether environmental, such as biological attack, ultraviolet degradation, freeze, thaw, etc., or structural defects, such as cracks, movement, or distortion.
      4. Architectural features will be repaired rather than replaced wherever possible. Repair or replacement of missing features will be based on accurate duplications rather than on conjectural designs.
      5. Work which requires existing features to be removed, cleaned and reused shall be accomplished without damage to the material itself, to adjacent materials, or the substrate.
      6. Existing features removed from the building which are to be reinstalled shall be carefully labeled and stored within the building in a place where they will not be damaged or obstruct other work.
      7. New or replacement materials/features will be permanently marked in an unobtrusive manner to distinguish them from original fabric. The manner of identification and location of these marks shall be recorded in permanent building records.
      8. Identify the historic importance of the material or feature. The item's merit, in terms of age, uniqueness of design, materials, size, technological development, association with persons or events, exceptional workmanship or design qualities, must be understood before decisions regarding repair, maintenance and preservation can be made.
      9. Statement of Non-Compliance: Wherever it is necessary to proceed with the use of products, under conditions which do not comply with the requirements (because of time schedule difficulties or other reasons which the supervisor determines that are crucial to the project), prepare a written statement for the RHPO's Record indicating the nature of the non-compliance, the reasons for proceeding, the extra or precautionary measures taken to ensure the best possible work, and the names of the individuals concurring with the decisions to proceed with the work.
      10. When cleaning, avoid overcleaning. Aim for achieving 85% clean. Most damage occurs when attempting to clean the last 15%.
        1. Do not use acids or flame tools to strip paint from stone, as it will damage the surface.
        2. Do not use steel or metal spatulas or tools to scrape stone because of the likelihood of scratching, chipping, gouging, or otherwise marring the surface.


  1. Product Data (when applicable):
    1. Submit to RHPO manufacturer's technical data for each product indicated including chemical analysis, recommendations for their application and use, and any other available technical data. Include test reports and certifications substantiating that products comply with requirements.
  2. Samples:
    1. Clearly labelled samples of all materials to be used on the job should be submitted to the RHPO for approval before work starts.
    2. The approved samples will become the standard materials used on the job. Substitutions will not be permitted without written approval from the RHPO.
  3. Quality Control Submittals:
    1. Submit written program for each phase of process including protection of surrounding materials during operations. Describe in detail materials, methods and equipment to be used for each phase of work.
    2. If alternative methods and materials to those indicated are proposed for any phase of work, provide written description to RHPO, including evidence of successful use on other, comparable projects, and program of testing to demonstrate effectiveness for use on this project.
    3. The contractor should supply proof of work on this type of project by submitting a list of pertinent projects the subcontractor has worked on which includes the scope of work, the budget for the scope of work, and a way to
    4. contact the owner and architect of each project.
  4. Design Data/Test Reports/Certificates:
    1. Routine testing of proposed materials, and of final work for compliance with the procedure will be carried out by the RHPO or his\her appointed representative.
      1. Cleaning methods should be tested prior to selecting the one for use. The simplest and least aggressive method(s) should be selected.
      2. The level of cleanliness desired also should be determined. A like-new appearance is both inappropriate and requires an overly harsh cleaning method.
      3. If test results show that performance criteria are not met, removal and repair of rejected work should be performed.


  1. Qualifications:
    1. Restoration Specialist: Work must be performed by a firm having not less than five years successful experience in comparable projects and employing personnel skilled in the processes and operations indicated. Project supervisor must have five years experience in work similar to this procedure. Additional personnel must also have experience.
    2. A supervisory craftsperson will be present when a craftsperson begins to perform the work in order to explain any procedures. Any modification of the written procedures will be made at that time.
    3. The supervisory craftsperson shall also be present during the work to instruct personnel as required.
      1. Source of Materials: Obtain materials from a single source for each type material required.
  2. Regulatory Requirements:
    1. Engage an approved independent testing laboratory to examine materials prior to use and continuously inspectthe work for compliance with this procedure and any related documents.
    2. The required research report and manufacturer's data shall be at the site and used for reference.
    3. Conform with all applicable safety guidelines.
    4. For Cleaning: Comply with municipal and Federal regulations governing cleaning, chemical waste disposal, scaffolding and protection of adjacent surfaces.
  3. Mock-ups: After acceptance of the list of materials and proposed method of cleaning, repair or refinishing, a representative sample area shall be cleaned, repaired or refinished as specified.
    1. Employ the method proposed and accepted for use. Obtain acceptance of the sample area from the RHPO before proceeding with remainder of the procedure.
    2. Maintain the sample area in its accepted condition until final acceptance of the completed work. Manufacturer's Representative should be present during mock-up and its inspection for approval. Sample work should be preformed in an area approved by the RHPO.
  4. For Cleaning:
    1. Before cleaning, all drains to be used should be tested to ensure they are functioning properly. Any clogged drains should be reported immediately.
    2. During cleaning, prevent cleaning residue from entering the drains or drain lines. Drains or drain lines that become blocked with cleaner residue must be cleaned out immediately.


  1. Packing and Shipping: Deliver materials to site in manufacturer's original and unopened containers and packaging, bearing labels as to type and names of products and manufacturers.
  2. Acceptance at Site: Handle materials in accordance with project safety guidelines and manufacturer's recommendations.
  3. Storage and Protection:
    1. Every effort must be made to use and reuse materials that are original to the structure. When removed from their rightful place, these materials must be stored under cover inside the building where they cannot be damaged.
    2. When pieces are to be removed, mark pieces inconspicuously in a consistent manner as to their original location. Document original position and label accordingly.
    3. If salvage material is to be used, treat it as new or original material with regard to its storage.
    4. Protect all materials during storage and construction from wetting by rain, snow or ground water, and from intermixture with earth or other types of materials.
    5. Protect materials from deterioration by moisture and temperature.
      1. Store cementitious materials off ground, under cover and in a dry location. Protect liquid components from freezing.
      2. Comply with manufacturer's recommendations for minimum and maximum temperature requirements for storage.
      3. Store all chemicals in metal cabinets. No cans shall be left open or out of the cabinet overnight.


  1. Environmental Requirements:
    1. Proceed with the work only when forecasted weather conditions are favorable.
    2. Wet weather: Do not attempt repairing of feature in raining or foggy weather. Do not apply primer, paint, putty, or epoxy when the relative humidity is above 80%. Do not remove exterior elements of structures when rainis in the forecast or in progress.
    3. Work in the shade when the temperature is above 75 degrees F. Work around the structure in the shade away from the sun.
    4. Do not perform exterior wet work when the air temperature is below 40 degrees F.
    5. NEVER begin cleaning, patching, etc. when there is any likelihood of frost or freezing.
    6. If cleaning is done in very hot, sunny weather, the feature/area should be shielded from excessive heat by hanging protective netting or tarpaulins around it.
    7. No cleaning shall be executed when either the air or the masonry surface temperature is below 45 degreesF, 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.
    8. Perform cleaning and rinsing of the exterior masonry only during daylight hours.
    9. Hot weather maximum application temperatures:
      1. paint - 85 degrees F
      2. putty - 80 degrees F
      3. epoxy - 80 degrees F
    10. Cold weather minimum application temperatures:
      1. paint - 50 degrees F
      2. putty - 50 degrees F
      3. epoxy - 55 degrees F
  2. Existing Conditions: Check manufacturer's literature for precautions and effects of products and procedures on adjacent building materials, components, and especially vegetation.


  1. Preventive Maintenance and Repair activities should be scheduled during appropriate environmental conditions to avoid weather related failures.
  2. Submit a work schedule indicating the proposed timing and extent of the work.
  3. Co-ordinate the work schedule with that of other trades on site.
  4. When cyclical maintenance work requires the use of high ladders and other access equipment, perform as many work items as possible.


  1. Do not change sources or brands of materials during the course of the work.
  2. All necessary precautions shall be taken to protect all parts of the building not being cleaned or repaired from effects of the work, including excessive amounts of water that should not be allowed to pond in any area. Also provide protection as required to prevent damage to adjacent property.
  3. Provide protection against the spread of dust, debris and water at or beyond the work area by suitable enclosures of sheeting and tarpaulins.
  4. Provide masking or covering on adjacent surfaces and permanent equipment. Secure coverings without the use of adhesive type tape or nails. Impervious sheeting which produces condensation should not be used.
  5. Prevent the entry of dust, debris and water into the building by sealing all openings.
  6. Provide protection from water damage to building, structure, or building contents as required.
  7. Protect all landscape work adjacent to or within maintenance work areas:
    1. Provide plank barriers to protect tree trunks. Bind spreading shrubs.
    2. Covering should allow plants to breathe and should be removed at the end of each work day. Do not cover plant material with a waterproof membrane for more than 8 hours at one time.
    3. Set scaffolding and ladder legs away from plants. Pruning requests should be directed to the RHPO.
  8. 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 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 designated representative. Do not begin work of this Section until the drains are in working order.
  9. 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 any other solids because of work performed under this Contract.
  10. Scaffolding, ladders and working platforms, required for the execution of this work should be provided. These items should not be attached to the building.