1、Designation: C1496 09Standard Guide forAssessment and Maintenance of Exterior Dimension StoneMasonry Walls and Facades1This standard is issued under the fixed designation C1496; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide outlines how to visually assess exterior stonemasonry walls and facades to determine their general c
3、ondi-tion. Examining key features of the construction can helpidentify and diagnose problems which require repairs orcorrective action. Such an examination can expose conditionswhich may be addressed with maintenance and minor repairs,or may require expert assistance. This guide is not intended tobe
4、 used for buildings requiring major exterior rehabilitation orstructural repairs.1.1.1 This guide applies to walls of solid stone or dimensionstone used as a cladding. Stone cladding is typically connectedto a backup material with a variety of anchoring methods,including traditional hand-set masonry
5、 anchors such as straps,dowels, cramps, hook-and-eyes, dove-tails, wire ties, and thelike. Joints between stones in these types of buildings areusually filled with mortar or sealant. Sealant-filled joints areusually designed to accommodate structural and thermal move-ments.1.2 This guide specificall
6、y excludes dimension stone used ininterior building surfaces, flooring or paving, slate dimensionstone used as roofing. Though they share some similar assess-ment and maintenance concerns, thin stone (less than 2 inchesnominal thickness) exterior cladding, and stone cladding at-tached to metal flame
7、s are also excluded due to their uniquedesign characteristics and performance requirements.Althoughprocedures and cautions listed herein may apply to walls andfacades containing semi-dimension, or partially sized, stone inthe form of split-face, or rubble and to stone-facade concretepanels, the guid
8、e is not specifically directed to such stone use.It does not address removal of small-area stains.1.3 This guide offers an organized collection of informationor a series of options and does not recommend a specific courseof action. This document cannot replace education or experi-ence and should be
9、used in conjunction with professionaljudgment. Not all aspects of this guide may be applicable in allcircumstances. This ASTM standard is not intended to repre-sent or replace the standard of care by which the adequacy ofa given professional service must be judged, nor should thisdocument be applied
10、 without consideration of a projects manyunique aspects. The word “Standard” in the title of thisdocument means only that the document has been approvedthrough the ASTM consensus process.1.4 The values stated in either inch-pound units or SI unitsare to be regarded separately as standard. The values
11、 stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its
12、 use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C119 Terminology Relating to Dimension StoneC1515 Guide for Cleaning of
13、Exterior Dimension Stone,Vertical And Horizontal Surfaces, New or Existing3. Terminology3.1 Terms used in this guide are defined in TerminologyC119.3.2 Definitions of Terms Specific to This Standard:3.2.1 crack monitorany of the several two-part devicesthat can be attached to stone masonry in such a
14、 way that theycan span cracks in order to periodically measure changes incrack width thereby indicating movement.3.2.2 dutchmanrepair used to patch stone masonry with asection of new stone. The damaged area within a particularstone element is removed. The remaining void is trimmed to aregular shape.
15、Anew piece of stone, or “dutchman,” is cut frommatching stone cut slightly smaller than the area to be filled. It1This guide is under the jurisdiction of ASTM Committee C18 on DimensionStone and is the direct responsibility of Subcommittee C18.07 on EnvironmentalProperties, Behavior, and Cleaning.Cu
16、rrent edition approved Sept. 15, 2009. Published October 2009. Originallyapproved approved in 2001. Last previous edition approved in 2001 as C149601.DOI: 10.1520/C1496-09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For An
17、nual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.is installed using dowels or some other mechanical attachment,then adhered
18、, or mortared into place.3.2.3 exfoliationdeterioration or loss of certain types ofstone in the form of flakes, scales, and layers.3.2.4 professional assistanceindependent opinions andrecommendations provided by persons having expertise in theassessment and repair of stone masonry. Such professional
19、smay include independent consultants such as architects, engi-neers, material scientists such as mineralogist or geologists, orstone masonry contractors.3.2.5 thickstones with a nominal bed-depth of 2 in. 5 cmor more.4. Significance and Use4.1 This guide attempts to provide information to assistbuil
20、ding owners and managers with limited knowledge of stoneconstruction to recognize basic problems with performance offacades, and to keep them in good condition through periodicinspections and maintenance. Increased awareness of thebehavior of stone masonry facades and associated materialscan reduce
21、maintenance and replacement costs by addressingproblems and deterioration early.4.2 The objective of all maintenance should be to limitdeterioration through early intervention.4.3 When it appears damage to stone support elements hasoccurred, professionals should be consulted to evaluate thesupport c
22、onditions, as well as recommend methods to restorethe buildings integrity and preserve public safety.5. Introduction5.1 An effective maintenance program for exterior stonemasonry should incorporate preventive maintenance among itskey elements. Early attention to problems, and simple mea-sures to rem
23、edy them, will often avoid costly renovation later.This guide is intended to help interested personnel locate suchproblem areas, better understand potential causes of stonedeterioration, and identify appropriate corrective measures forthe observed deficiencies.5.2 Maintenance supervisors should unde
24、rstand how theirbuilding is constructed to apply this guide and better maintaintheir buildings. Employing a professional to assist them ininterpreting pertinent drawings and documents, and initiallyinspecting conditions should help them become effectiveobservers of stone performance.5.3 This guide l
25、ists many typical problems that can affectstone masonry, facades. It describes likely causes, and dis-cusses common repair methods. All initial attempts at repairsshould be done under the observation of a professional toensure the use of proper materials and techniques.5.4 Personnel responsible for
26、stone facade maintenanceshould be familiar with the systems used in the construction oftheir buildings on at least an elementary level. Prior toinspections, they should be briefed by personnel knowledge-able about the building and its construction, particularly thestone wall system. This background
27、should help in determiningwhen the engagement of a professional should be considered.5.5 In cases where the building or its facade has cultural,civic, historic, or architectural significance, consultation with aspecialist is recommended.6. Guidelines for Inspections6.1 Schedule InspectionsSchedule a
28、nd perform semi-annual inspections of stone wall elements. Inspect all eleva-tions of the building. A walk-around visual survey with acamera and binoculars should be a minimum procedure. Useadjacent buildings roofs and windows to gain same-levelaccess, to examine building facades and associated elem
29、ents.Use building windows and set-backs where possible foradditional vantage points. If the available access is not suffi-cient to perform the inspections, then consider methods, asoutlined in 6.3. Photograph any observed distress or problemareas for later reference in determining appropriate repair
30、s.6.2 Condition Documentation/MonitoringKeep accurateand cumulative records of inspection findings. Buildings con-structed of thick dimension stone with mortar or sealant-filledjoints react slowly to environmental forces. Knowledge of thetiming of a conditions onset and understanding its progress ai
31、din assessing the distressed condition. Monitor critical ordeteriorated areas between scheduled inspections. Use mea-surements or crack monitors to measure changes in cracks,increasing lippage between stones (stones projecting or retreat-ing in plane from the adjacent stones), or other changes anddi
32、splacements in stone position. Well-kept records will aid inthe diagnosis of the specific causes of the conditions observed,should more experienced professionals be required.6.3 Tall BuildingsInspections of buildings with heightsthat exceed those readily observable with binoculars, or withlimited va
33、ntage points require more detailed planning. It willbe necessary to view representative areas of the facades fromsuspended or fixed scaffolding, mobile work platforms, orpersonnel lifts to adequately observe existing conditions.7. Procedure for Evaluation of Stone Conditions7.1 At a minimum, the fol
34、lowing procedure should be usedas a guide to decide an appropriate course of action forobserved deficiencies as part of an inspection and maintenanceprogram for stone masonry facades.7.1.1 Identify and document the defects.7.1.2 Note the extent of the defects, patterns or concentra-tions of distress
35、.7.1.3 Postulate the likely causes.7.1.4 Perform necessary maintenance or obtain assistancewith repairs:7.1.4.1 If the condition is stable and does not appear to beprogressive, perform appropriate maintenance, and simple ortemporary repairs.7.1.4.2 If the cause is not apparent, and the conditionappe
36、ars stable and not progressive, monitor the condition andconsult with professionals to determine the cause and appro-priate repairs.7.1.4.3 If the observed conditions are considered dangerousor progressive, obtain professional assistance immediately.8. Maintenance8.1 Routine MaintenanceMany problems
37、 can begin orworsen due to neglect of routine maintenance. Stone masonryitself, when used in an exterior application, requires periodicjoint repairs, such as sealant replacement, tuck pointing, andC1496 092cleaning. Stone facade components can also be affected by alack of maintenance of other buildi
38、ng systems, such as roofs,parapets, windows, and flashing.8.2 CleaningRegular cleaning is also critical to the longterm durability of natural stone facades, as well as theirappearance. Cleaning methods should be selected that do notdamage the stone. Cleaning methods and materials should befirst test
39、ed, from the least to the most aggressive, to determinethe mildest treatment that provides satisfactory results. Prior toimplementing a cleaning technique building-wide, test areasshould be cleaned using the proposed methods. The areasshould be evaluated for a minimum period of six weeks toassess th
40、e results. Improper selection of cleaning chemicalsand procedures will produce unsightly and irreversible damageto the appearance, and potentially the structural integrity, of thestone facade components. Refer to Guide C1515 for proce-dures for cleaning exterior stone.9. Areas of Focus for Inspectio
41、n9.1 Moisture or Water StainingLook for signs of moistureon interior and exterior surfaces, as well as throughout thestone wall system. Water penetration can lead not only todeterioration of interior finishes, but also to stone and jointmaterial degradation and corrosion of anchor system compo-nents
42、 if the water is trapped behind or within the wall or facadesystem for prolonged periods. Water absorbed into stone andjoint materials can cause dimensional changes, potentiallyreducing clearances and creating stress concentrations.Trapped water can freeze and expand, causing the stone toweaken, and
43、 eventually spall or crack. Joint materials may alsodeteriorate as a result.9.1.1 Water can also carry minerals, chemicals, or othercontaminants that can be deposited on or within the stone andjoints, causing discoloration, staining, or deterioration.9.1.2 Wetness, staining, or darkening may be due
44、to trappedmoisture. Discoloration or deposition of efflorescence (a pow-dery white or gray accretion on stone faces) may also beevidence of moisture entry, or “rising damp.” Rising damp is acondition in which the stones appear darker due to waterwicking into the stone by capillary action from a wate
45、r sourcealong one or more edges of the stone, such as at the base of abuilding.9.2 JointsEvery inspection should include a review ofeach joint between stones. Document anomalous and suspectconditions photographically, especially in areas of accelerateddeterioration. Where a problem is suspected, it
46、is useful tocompare photographs taken at various times to establish theprogression and rate of deterioration.9.2.1 Look for missing mortar and sealant, for cracks inmortar, for partings between mortar or sealant and the stone,for non-uniform joint sizes due to tight, closed or openingjoints, and for
47、 lipped stones. Connections between stones andnon-stone materials such as windows and other openings areoften particularly susceptible to racking and eccentric move-ment. Check for plugged weep holes throughout the wallsystem. Compare the width of expansion, control, and con-struction joints. Look f
48、or wider or narrower tops and bottomsof such joints.9.3 StoneCracks and spalled areas at or near joints mayindicate excessive compression loading, anchor failure, andenvironmental deterioration, among other things. Misalign-ment of stone across a series of joints may indicate local orstructural buil
49、ding movements.9.3.1 Surface deterioration may take the form of exfoliation(where the surface is lost in thin layers), spalling, powdering,or chipping. These conditions can be particularly prevalentwhere chloride-based de-icing products used on paving sys-tems aggravate the effects of freeze-thaw cycling Both calciumchloride (CaCl2) and sodium chloride (NaCl) are commonlyused. Both will cause damage to stone surfaces.9.4 FacadesSight along walls for bulging areas, particu-larly in those containing smaller stones. Look for areas ofdifferent, or changing, colors. Co
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