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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 8221-2:2000 ICS 91.040
2、.01 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Code of practice for cleaning and surface repair of buildings Part 2: Surface repair of natural stones, brick and terracotta Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 06:02:00 GMT+0
3、0:00 2006, Uncontrolled Copy, (c) BSI This British Standard, having been prepared under the direction of the Sector Committee for Building and Civil Engineering, was published under the authority of the Standards Committee and comes into effect on 15 April 2000 BSI 04-2000 The following BSI referenc
4、es relate to the work on this standard: Committee reference B/209 Draft for comment 96/18387 DC ISBN 0 580 33136 9 BS 8221-2:2000 Amendments issued since publication Amd. No.DateComments Committees responsible for this British Standard The preparation of this British Standard was entrusted by Techni
5、cal Committee B/209, General building codes, to Technical Subcommittee B/209/7, Cleaning and surface repair of buildings, upon which the following bodies were represented: Chartered Institute of Building Construction Confederation Department of the Environment, Transport and the Regions Construction
6、 Directorate National Council of Building Material Producers National House-Building Council Royal Institute of British Architects Royal Institution of Chartered Surveyors The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Brick Development
7、Association British Ceramic Research Ltd. Concrete Society Council for Aluminium in Building Council for the Care of Churches Department of the Environment, Transport and the Regions Represented by the Building Research Establishment Ecclesiastical Architects and Surveyors Association English Herita
8、ge Historic Scotland London Transport Mortar Producers Association Limited National Grp Construction and Engineering Federation Society for Protection of Ancient Buildings Stone Federation UK Steel Association Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 06:0
9、2:00 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 8221-2:2000 BSI 04-2000i Contents Page Committees responsibleInside front cover Forewordii Introduction1 1Scope1 2Normative references1 3Definitions2 4Considerations affecting surface repair decisions3 5Procedures associated with surface repair4 6Po
10、inting and bedding mortars6 7Repointing10 8Stone masonry repair11 9Brickwork repair13 10Repair of terracotta and faience15 11Surface coverings17 12External render repairs17 13Treatment and protection of surfaces17 14Coatings19 15Maintenance of the exteriors of buildings19 Annex A (informative) Non-d
11、estructive and key-hole survey methods20 Annex B (informative) Use of consolidants on weathered stone and other porous materials20 Bibliography23 Table 1 Austenitic stainless steel grades and uses5 Table 2 Mortar types and applications7 Table 3 Mortar mixes for groups A1 to D57 Table 4 Non-hydraulic
12、 mortar mixes8 Table 5 Lime mortar mixes with pozzolanic additives8 Table 6 Classification of hydraulic limes9 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 06:02:00 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii BSI 04-2000 BS 8221-2:2000 Foreword This British
13、 Standard has been prepared by Subcommittee B/209/7. Together with Part 1, it supersedes BS 6270-1:1982 and BS 6270-2:1985, which are withdrawn. This part of BS 8221 gives guidance on surface repair of external facades of buildings. It has been prepared in parallel with BS 8221-1, which provides gui
14、dance on cleaning. This code of practice covers repointing and types of mortar, repair of stone masonry, brickwork, terracotta and faience, use of surface coverings, external render repair, and use of consolidants on weathered stone and other porous building materials. This code of practice takes th
15、e form of guidance and recommendations. It should not be quoted as if it were a specification and care should be taken to ensure that claims of compliance are not misleading. WARNING This British Standard calls for the use of materials that may be injurious to health or damaging to the environment i
16、f adequate precautions are not taken. The recommendations given in this standard refer only to technical suitability and do not absolve the user from legal obligations relating to health and safety. A British Standard does not purport to include all the necessary provisions of a contract. Users of B
17、ritish Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 24, an inside back cover and a back
18、cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 06:02:00 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 04-20001 BS 8221-2:2000 Introduction This code of prac
19、tice is intended to provide building owners, architects, surveyors, engineers and contractors general information concerning surface repairs of buildings. This code of practice recommends investigative procedures for selecting a suitable repair process. It describes a range of repair and conservatio
20、n procedures and some problems that may be encountered. Before carrying out surface repairs, it is essential to ascertain any factors causing decay, such as open joints allowing water ingress, migrating salts from a backing wall, run-off from limestone, or a corroding metal tie/armature. 1 Scope Thi
21、s British Standard provides recommendations for surface repair of natural stones, clay brick, calcium silicate brick, glazed and unglazed terracotta, and faience masonry in buildings. It covers repointing and selection of mortars, and provides guidance on treatment for protection of surfaces. Surfac
22、e repairs of concrete and structural repairs are not covered by this code of practice. For guidance on structural repairs, reference should be made to BS 5390 and BS 5628-1. 2 Normative references The following normative documents contain provisions that, through reference in this text, constitute p
23、rovisions of this British Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. For undated references, the latest edition of the publication referred to applies. BS 12:1996, Specification for Portland cement. BS 63-2:1987, Road aggregates
24、 Specification for single-sized aggregate for surface dressing. BS 187:1978, Specification for calcium silicate (sand-lime and flint-lime) bricks. BS 812-103-1, Testing aggregates Method for determination of particle size distribution Sieve tests. BS 882:1992, Specification for aggregates from natur
25、al sources for concrete. BS 890:1995, Specification for building limes. BS 1014:1975, Specification for pigments for and Portland cement products. BS 1139 (all parts), Metal scaffolding. BS 1178:1982, Specification for milled lead sheet for building purposes. BS 1199 and 1200:1976, Specifications fo
26、r building sands from natural sources. BS 1217:1986, Specification for cast stone. BS 2482:1981, Specification for timber scaffold boards. BS 2873:1969, Specification for copper and copper alloys Wire. BS 3148:1980, Methods of test for water for making concrete. BS 3892-1, Pulverized-fuel ash Specif
27、ication for pulverized-fuel ash for use with Portland cement. BS 3921:1985, Specification for clay bricks. BS 4551 (all parts), Methods of testing mortars, screeds and plasters. BS 4721:1981, Specification for ready-mixed building mortars. BS 4729:1990, Specification for dimensions of bricks of spec
28、ial shapes and sizes. BS 4887-1:1986, Mortar admixtures Specification for air-entraining (plasticizing) admixtures. BS 5224:1995, Specification for masonry cement. BS 5262:1991, Code of practice for external renderings. BS 5390:1976, Code of practice for stone masonry. BS 5628-1:1992, Code of practi
29、ce for use of masonry Structural use of unreinforced masonry. BS 5628-3:1985, Code of practice for use of masonry Materials and components, design and workmanship. BS 5838-2:1980, Specification for dry packaged cementitious mixes Prepackaged mortar mixes. BS 5973:1993, Code of practice for access an
30、d working scaffolds and special scaffold structures in steel. BS 6037:1990, Code of practice for permanently installed suspended access equipment. BS 6100 (all parts), Glossary of building and civil engineering terms. BS 6213:1982, Guide to selection of constructional sealants. BS 6431-17:1983, Cera
31、mic floor and wall tiles Method for determination of crazing resistance Glazed tiles. BS 6477:1992, Specification for water repellents for masonry surfaces. BS 6649:1985, Specification for clay and calcium silicate modular bricks. BS 6915:1988, Specification for design and construction of fully supp
32、orted lead sheet roof and wall coverings. BS 7913:1998, Guide to the principles of the conservation of historic buildings. BS 8210:1986, Guide to building maintenance management. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 06:02:00 GMT+00:00 2006, Uncontroll
33、ed Copy, (c) BSI 2 BSI 04-2000 BS 8221-2:2000 DD ENV 459-1:1995, Building lime Definitions, specifications and conformity criteria. BS EN 10088-2:1995, Stainless steels Technical delivery condition for sheet, plate and strip for general purposes. BS EN 10088-3:1995, Stainless steels Technical delive
34、ry conditions for semi-finished products, bars, rods and sections for general purpose. BS EN ISO 3506-1:1998, Mechanical properties of corrosion resistant stainless-steel fasteners Bolts, screws and studs. BS EN ISO 3506-2:1998, Mechanical properties of corrosion resistant stainless-steel fasteners
35、Nuts. PD 6472:1972, Guide to specifying the quality of building mortars. Control of Pesticides Regulations, 1986. The Lead Sheet Manual A Guide to Good Building Practice. 3 Definitions For the purposes of this British Standard, the terms and definitions in BS 6100 (some of which are repeated below f
36、or convenience) and the following apply. 3.1 armature austenitic stainless steel, copper or copper based alloy rods, wires or mesh set within a mortar repair to secure it to the parent stone and reinforce its layers 3.2 brick slip brick, either specially manufactured or cut, of the same height and l
37、ength as a header or a stretcher, and usually with a thickness of between 20 mm and 50 mm 3.3 conservation stabilizing and preventing or retarding further deterioration of masonry 3.4 crazing fine, hair-line stress relief cracks caused by inability of a glazed surface and the underbody to accommodat
38、e thermal and moisture movement NOTECrazing is also known as poor glaze fit. 3.5 cramp shaped piece of metal or slate, bedded into sinkings in stone units to tie them to each other or to their backing 3.6 Coade stone proprietary off-white terracotta body produced from a kaolinitic clay, containing t
39、itanium dioxide, feldspar as flux and quartz as glass-forming agent, and a grog of powdered prefired clay NOTECoade stone was manufactured by the Coade family between 1769 and 1820. 3.7 dowel short piece of material sunk or cast into adjacent hidden wall faces, to align or prevent movement of the fa
40、ces 3.8 engobe surface application by brush or spray of liquid clay, before firing, to provide an opaque, unglazed coloured finish on some forms of terracotta 3.9 faience masonry, similar to terracotta, with one or more surfaces covered with a clear or coloured glaze 3.10 fired-clay unit masonry uni
41、t formed from brick-earth, clay or shale, dried and burned NOTEFired-clay should not be confused with fireclay, which is used for making refractory bricks. 3.11 fireskin thin, smooth, outer layer on unglazed terracotta, containing a high proportion of fines NOTEIn traditional firing processes, fires
42、kin is vitrified to a greater degree than the body of clay beneath. Fireskin has a protective role and retention of it should be a priority in cleaning and repair works. 3.12 gauged brickwork soft bricks cut to shape and abraded to the size required 3.13 glaze mixed paste of fluxes and colouring ing
43、redients that becomes a thin, vitreous, transparent or coloured surface finish of glassy, opaque or translucent consistency on firing NOTEGlazes can be plain, mottled or textured and can range from high-gloss to egg-shell finish. Licensed Copy: London South Bank University, London South Bank Univers
44、ity, Fri Dec 08 06:02:00 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 04-20003 BS 8221-2:2000 3.14 grog inert filler added to a clay mixture before firing to control shrinkage 3.15 grout flowing material that sets after application, used to fill fissures and cavities 3.16 hydraulic lime binder of
45、limestone, clay, and calcium and magnesium carbonates, that sets and hardens by chemical interaction with water, both in water and in air NOTEHydraulic limes are classified as eminently, moderately or feebly hydraulic limes. 3.17 non-hydraulic lime binder consisting mainly of calcium hydroxide (high
46、 calcium lime) or magnesium carbonate (magnesian/dolomitic lime) that, when mixed with water, sets slowly by drying out and atmospheric carbonation NOTENon-hydraulic limes can be prepared and used as a putty or as a powder (hydrated lime). 3.18 piecing-in cutting out a decayed or damaged section of
47、masonry and inserting new NOTEPiecing in is also known as indenting. 3.19 slip casting method of manufacture of thin solid slabs, hollow blocks, or tiles, in which a suspension of clay particles in water, of liquid, creamy consistency, is poured into plaster moulds and allowed to dry solid before re
48、leasing, drying and firing 3.20 surface repair renewal, by minor replacement, of damaged or heavily weathered masonry surfaces with similar or compatible material 3.21 terracotta fired clay, fine textured and unglazed, usually yellow to brownish-red 4 Considerations affecting surface repair decision
49、s 4.1 General COMMENTARY Most surface repairs are concerned with prevention of moisture ingress or repair/replacement of decayed or damaged elements. Work to improve the weather resistance of buildings may relate to repair of surface defects likely to have a long-term detrimental effect on the whole or part of the structure, replacement of defective fixings, or reinstatement of the surface of a building after structural repairs. Work to improve the appearance of buildings may include repairs of decayed or damaged mouldings, surfac