1、Designation: C1496 11Standard 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 in.nominal thickness) exterior cladding, and stone cladding at-tached to metal flames a
7、re 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 guide i
8、s 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 use
9、d 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 wi
10、thout 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 inch-pound units are to be regardedas standard. The values given in parentheses are mathema
11、ticalconversions to SI units that are provided for information onlyand are not considered standard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and healt
12、h 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 Exterior Dimension Stone,Vertical And Horizontal Surfaces, New or ExistingE1971 Guide for Stewardship
13、 for the Cleaning of Commer-cial and Institutional Buildings3. 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 way that they
14、can 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.Anew piece of
15、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.Current edition
16、approved Oct. 1, 2011. Published November 20011. Originallyapproved in 2001. Last previous edition approved in 2009 as C149609. DOI:10.1520/C1496-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStanda
17、rds 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, or mortared into plac
18、e.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 professionalsmay include independen
19、t 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 cm)or more.4. Significance and Use4.1 This guide attempts to provide information to assistbuilding owners and manag
20、ers 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 maintenance and repla
21、cement 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 conditions, as well as
22、 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 remedy them, will often
23、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 understand how theirbuild
24、ing 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 lists many typical pro
25、blems 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 stone facade maintena
26、nceshould 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 should help in determ
27、iningwhen 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.5.6 When assessing the condition of exterior dimensionstone, and particularly any pr
28、oblems requiring action, theappropriate cleaning or repair methods should promote eco-efficiency, avoid any adverse impacts on humans present orinvolved, avoid any adverse impacts on the building structure,and reduce stress on the environment. See Guide E1971.Choices must be made on cleaning product
29、s and processes, andbuilding repair materials and method.5.6.1 Certain pertinent questions should be considered here:(1) how is the building used? (2) what type of dimension stoneand what finish was used? (3) is the dimension stone load-bearing or is the load carried by other materials such as steel
30、 orconcrete? (4) are there any issues relating to building age orarchitecture? (5) what criteria or measures will be used toevaluate the quality of cleaning and repairs?6. Guidelines for Inspections6.1 Schedule InspectionsSchedule and perform semi-annual inspections of stone wall elements. Inspect a
31、ll 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 elements.Use building windows and set-backs where possible foradditional
32、 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 repairs.6.2 Condition Documentation/MonitoringKeep accurateand cumulative
33、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 aidin assessing the distressed condition. Monitor critical ordeteriora
34、ted 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 anddisplacements in stone position. Well-kept records will aid inthe diag
35、nosis 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 vantage points require more detailed planning. It willbe necessary to
36、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 following procedure should be usedas a guide to decide an appropriate c
37、ourse 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.7.1.3 Postulate the likely causes.7.1.4 Perform necessary maintenan
38、ce or obtain assistancewith repairs:C1496 1127.1.4.1 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 conditionappears stable and not progressive, monitor the condition andco
39、nsult 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 can begin orworsen due to neglect of routine maintenance.
40、Stone masonryitself, when used in an exterior application, requires periodicjoint repairs, such as sealant replacement, tuck pointing, andcleaning. Stone facade components can also be affected by alack of maintenance of other building systems, such as roofs,parapets, windows, and flashing.8.2 Cleani
41、ngRegular 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 tested, from the least to the most aggressive, to determinethe mildest t
42、reatment 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 the results. Improper selection of cleaning chemicalsand procedures wi
43、ll 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 Inspection9.1 Moisture or Water StainingLook for signs of moistureon interior
44、 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 if the water is trapped behind or within the wall or facadesystem f
45、or 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 eventually spall or crack. Joint materials may alsodeteriorate as a
46、 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 to trappedmoisture. Discoloration or deposition of efflorescence (a
47、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 water sourcealong one or more edges of the stone, such as at the base of
48、 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 is useful tocompare photographs taken at various times to establish
49、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 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 for wider or narrower tops and bottomsof su
