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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 8000-9:1999 ICS 91.060
2、.30; 91.200 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Workmanship on building sites Part 9: Cementitious levelling screeds and wearing screeds Code of practice Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 06:02:05 GMT+00:00 2006,
3、Uncontrolled Copy, (c) BSI This British Standard, having been prepared under the direction of the Tecnical Committee B/544, was published under the authority of the Standards Policy and Strategy Committee and comes into effect on 15 December 1999 BSI 12-1999 The following BSI references relate to th
4、e work on this standard: Committee reference B/544/6 Draft for comment 96/105026 DC ISBN 0 580 33089 3 BS 8000-9:1999 Amendments issued since publication Amd. No.DateComments Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committe
5、e B/544, Plastering, rendering, dry lining, screeds and in situ flooring, to Subcommittee B/544/6, Screeds and in-situ floorings, upon which the following bodies were represented: Association of Concrete Industrial Flooring Contractors Association of Lightweight Aggregate Manufacturers Concrete Soci
6、ety Construction Confederation Contract Flooring Association Department of the Environment, Transport and the Regions European Resin Manufacturers Association Federation of Plastering and Drywall Contractors Federation of Resin Flooring Formulators and Applicators (FeRFA) Mastic Asphalt Council Mort
7、ar Producers Association National Federation of Terazzo-Marble and Mosaic Specialists National Specialist Contractors Council Quarry Products Association Scottish Master Plasterers Association Society of Chemical Industry Licensed Copy: London South Bank University, London South Bank University, Fri
8、 Dec 08 06:02:05 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 8000-9:1999 BSI 12-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Normative references1 3Terms and definitions1 4Materials handling and preparation1 4.1Checking, handling and site storage of materials an
9、d components1 4.2Preparation of work, materials and components2 5Laying levelling and wearing screeds5 5.1General5 5.2Bay sizes6 5.3Placing and compacting6 5.4Finishing7 5.5Surface treatments after laying8 5.6Inspection and testing8 5.7Curing screeds8 5.8Protection8 Bibliography9 Index10 Table 1 Eff
10、ects of standards of workmanship on screed performance3 Table 2 Guidance on changes in mix proportions of cement/sand screeds when damp sand is used4 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 06:02:05 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii BSI 12-19
11、99 BS 8000-9:1999 Foreword The preparation of this British Standard was entrusted by Technical Committee B/544, Plastering, rendering, dry lining, screeds and in situ flooring to Subcommittee B/544/6, Screeds and in situ floorings. It supersedes BS 8000-9:1989 which has been withdrawn. It makes reco
12、mmendations and gives guidance on basic workmanship for conventional types of building work. The recommendations given are not necessarily comprehensive; particular project documents, e.g. project specifications, may need to cover recommendations not dealt with by this code of practice. This code of
13、 practice is unique in that unlike other British Standards, it draws together recommendations given in other codes of practice. The purpose of this code of practice is to encourage good workmanship by providing the following: a) the most frequently required recommendations on workmanship for buildin
14、g work in a readily available and convenient form to those working on site; b) assistance in the efficient preparation and administration of contracts; c) recommendations on how designers requirements for workmanship can be satisfactorily realized; d) definitions of good practice on building sites f
15、or supervision and for training purposes; this guidance is not intended to supplant the normal training in craft skills; e) a reference for quality of workmanship on building sites. It is recognized that design, procurement and project information is conducive to good workmanship on site. This code
16、of practice has generally been arranged in accordance with the Common Arrangement of Work Sections 1 for building work. BS 8000 comprises the following parts. Part 1: Code of practice for excavation and filling; Part 2: Code of practice for concrete work; Part 3: Code of practice for masonry; Part 4
17、: Code of practice for waterproofing; Part 5: Code of practice for carpentry, joinery and general fixings; Part 6: Code of practice for slating and tiling of roofs and claddings; Part 7: Code of practice for glazing; Part 8: Code of practice for plasterboard partitions and dry linings; Part 9: Code
18、of practice for cementitious levelling screeds and wearing screeds; Part 10: Code of practice for plastering and rendering; Part 11: Code of practice for wall and floor tiling; Part 12: Code of practice for decorative wallcoverings and painting; Part 13: Code of practice for above ground drainage an
19、d sanitary appliances; Part 14: Code of practice for below ground drainage; Part 15: Code of practice for hot and cold water services (domestic scale); Part 16: Code of practice for sealing joints in buildings using sealants. This part is based upon, and consistent with the guidance contained in BS
20、8204 which covers the design aspects of the subject matter, (including design, materials and other related aspects) in addition to workmanship on site. BS 8204-1 gives recommendations for concrete bases to receive in-situ wearing screeds of concrete, polymer modified cementitious flooring, terrazzo,
21、 mastic asphalt, synthetic resin and magnesium oxychloride. It also covers both bases and levelling screeds to receive flexible floor coverings such as textiles, linoleum, polyvinyl chloride, rubber and cork and rigid floorings such as wood block and strip, ceramic tiles and natural stone. Licensed
22、Copy: London South Bank University, London South Bank University, Fri Dec 08 06:02:05 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 12-1999iii BS 8000-9:1999 The text of this part of BS 8000 includes commentaries. These commentaries are separately identified and are intended to be for guidance only
23、 and do not form part of the recommendations. They refer, unless otherwise stated, to the clause which immediately precedes each commentary. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct applica
24、tion. 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 to iv, pages 1 to 10, an inside back cover and a back cover. The BSI copyright notice displayed in this document
25、indicates when the document was last issued. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 06:02:05 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ivblank Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 06:02:05 GMT+00:00 2006
26、, Uncontrolled Copy, (c) BSI BSI 12-19991 BS 8000-9:1999 1 Scope This part of BS 8000 gives recommendations on laying cementitious levelling screeds and wearing screeds. This part does not cover laying concrete bases or direct finished concrete wearing surfaces. Recommendations on these are given in
27、 BS 8204-1 and BS 8204-2 respectively. Recommendations on design aspects of levelling screeds are given in BS 8204-1 and for wearing screeds, in BS 8204-2. NOTEThis code of practice includes supplementary elements in the form of commentaries to assist in its use and understanding. Compliance with th
28、e commentaries is not necessary in order to be able to claim conformity with the standard. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of BS 8000. For dated references, subsequent amendments to,
29、 or revisions of, any of these publications do not apply. For undated references, the latest edition of the cited publication applies. BS 6100-1.3.3:1987, Glossary of building and civil engineering terms Part 1: General and miscellaneous Section 1.3: Parts of construction works Subsection 1.3.3: Flo
30、ors and ceilings. BS 6100-6.1:1984, Glossary of building and civil engineering terms Part 6: Concrete and plaster Section 6.1: Binders. BS 6100-6.2:1986, Glossary of building and civil engineering terms Part 6: Concrete and plaster Section 6.2: Concrete. BS 6100-6.3:1984, Glossary of building and ci
31、vil engineering terms Part 6: Concrete and plaster Section 6.3: Aggregates. 3 Terms and definitions For the purposes of this part of BS 8000, the definitions given in BS 6100-1.3.3:1987, BS 6100-6.1:1984, BS 6100-6.2:1986 and BS 6100-6.3:1984 and the following apply. 3.1 base building element that p
32、rovides the support for a screed and any other building element 3.2 direct finished base slab base that is suitably finished to provide a wearing surface or to receive directly the flooring to be applied without the need for a levelling screed 3.3 flooring uppermost fixed layer of a floor that is de
33、signed to provide a wearing surface 3.4 screed material mixture comprising cement, aggregates, water and in some cases, admixtures and/or additives 3.5 screed layer of material laid in situ, directly onto a base, bonded or unbonded, or onto an intermediate layer or insulation layer, for one or more
34、of the following purposes: to obtain a defined level; to carry the final flooring; to provide a wearing surface. 3.6 levelling screed screed suitably finished to obtain a defined level and to receive the final flooring 3.7 wearing screed screed that serves as a flooring 3.8 surface regularity (flatn
35、ess) deviation in height of the surface of a flooring layer over short distances in a local area 3.9 in situ crushing resistance resistance of levelling screeds to the crushing effect of imposed loads and traffic in service 4 Materials handling and preparation WARNING. When Portland cement is mixed
36、with water, or even becomes damp, alkalis are released which can be harmful to the skin. The effect depends on the length of contact, any abrasion, the individual and the part of the body involved. Suitable protective clothing should be worn. If eyes are affected they should be washed out immediatel
37、y and medical advice sought without delay. 4.1 Checking, handling and site storage of materials and components 4.1.1 Checking Check delivery tickets for the materials against the specification and, if necessary, refer to the supplier immediately. Check visually that the materials as ordered are as s
38、tated on the delivery tickets. In particular observe that: a) cement is of the type and grade specified; b) sand is clean and well graded; c) coarse aggregates are of the correct single or graded sizes and are clean. Licensed Copy: London South Bank University, London South Bank University, Fri Dec
39、08 06:02:05 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 BSI 12-1999 BS 8000-9:1999 4.1.2 Handling and site storage 4.1.2.1 Ready-to-use retarded mortar for screeds Unload the mortar into clean containers or onto a clean impervious platform. If the mortar is not used immediately on delivery, protect
40、 it from the weather and cover it to prevent water loss. 4.1.2.2 Cement in bags Where the cement is to be stored for later use, (unless there are small quantities only), store as follows. a) Store in a dry, weatherproof, enclosed shed or building with a dry floor. For a solid floor, store off the fl
41、oor, e.g. on pallets. b) Stack bags away from walls, closely packed together but not more than eight bags high. Cover stacks with a tarpaulin or polyethylene sheet. c) Stack bags so that consignments can be used in the order of delivery. d) Check cement for deterioration when taken out of storage an
42、d discard if lumpy. In the case of small quantities for immediate use, if not stored in a shed or building, stand the bags well clear of the ground, e.g. on a pallet, and cover with a tarpaulin or polyethylene sheet so that all the bags are wholly protected from wind and rain. COMMENTARY Even if cem
43、ent is protected from rain, moisture in the air will gradually cause its deterioration. Even in good conditions cement will eventually go lumpy and give lower strength. 4.1.2.3 Sand and aggregates a) Keep different sizes and types of sand and aggregates strictly separate. b) Store on a hard, clean b
44、ase which permits free drainage. c) Keep free from leaves, rubbish, dirt or other deleterious material. d) In frosty weather cover the stockpiles to prevent freezing. COMMENTARY In very cold weather it can be necessary to use some form of insulating covering. Polyethylene sheets will keep out rain a
45、nd dirt but do not offer much protection from frost. In very hot sunny weather it is advisable to cover or to shade stocks to prevent them getting excessively hot. e) Store sand and aggregates that are delivered in bags, in the bags until required for use. 4.1.2.4 Reinforcement Avoid deformation dur
46、ing handling. Store off the ground on supports close enough together to prevent the reinforcement from sagging unduly. Cover to keep dry and clean. 4.2 Preparation of work, materials and components NOTELevelling screeds provide surfaces that are intended to receive a flooring. Wearing screeds are in
47、tended to provide the finished surface. Screeds are liable to crack or curl mainly from the influence of drying shrinkage. Screeds can be crushed under load due to insufficient cement, inadequate mixing and/or compaction. Careful design and skilled workmanship can minimize the risk of these defects.
48、 When a failure does occur, it is often inconvenient and costly to remedy as it can occur during practical completion of construction or when the building is occupied. Disregarding the guidance and requirements given in this part of BS 8000 is likely to increase the risk of failure. 4.2.1 Effect of
49、standards of workmanship on screed performance The effects of standards of workmanship on the various tasks carried out in constructing screeds and their consequent performance are summarized in Table1. 4.2.2 Inspection and preparation of bases 4.2.2.1 Level Check the base for level before preparing it to receive the screed (and insulation if specified), to ensure that the specified minimum thickness of screed can be laid over the whole area. If the base is too high, seek further instructions. 4.2.2.2 Monolithic wearing screeds N