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Building Regulations 1997
Technical Guidance Document A
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Amendments issued since publicationTechnical Guidance Document A - Structure
Government of Ireland 2005
Diagram 15 : Wind speeds map updated.A(viii)
Standards and other references:-
Replace I.S. EN 197 Part 1 and 2 with I.S. EN 197 - 1: 2001
Reference to I.S. 1:1991 in the following sections is hereby replaced by:
- Design provisions. item 22.214.171.124(c). cement (type CEM1) I.S. EN 197 - 1: 2001
- Standards and other references.I.S. EN 197 - 1: 2001
Standards and other references, insert :
BS 6399 : Loading for buildings Part 2 : Code of Practicefor wind loads.
Diagram 15 : additional Diagram 15A included.A(iv)
1.2.1, Loading: insert between BS 6399: Parts 1 and 3 :
BS 6399 : Part 2 (For wind loads and using the windspeed map in Diagram 15A)
1.0.1, last sentence : replace with :
Wind loads should be in accordance with CP3 : Chapter V : Part 2, using wind speeds based on Diagram15 of this Technical Guidance Document or BS 6399: Part 2 using wind speeds based on Diagram 15A of thisTechnical Guidance Document.
Transitional Arrangements:- Replace 1 January 1998 with1 July 1998
Text AffectedAmd. No.
Introduction 2Transitional Arrangements 2The Guidance 2Existing Buildings 2Technical Specifications 2Materials and Workmanship 2Interpretation
Part A: The Requirement 3
SECTION 1 STRUCTURE - LOADING AND GROUND MOVEMENTIntroduction 4Other approaches 5Definitions 5
Sub-section 1 Sizes for certain structural elements for houses and other small buildings 6
1.1.1 Part 1 Basic requirements for stability 61.1.2 Part 2 Sizes of certain timber floor, ceiling and roof members in houses 6
Application 6The use of this part 6
1.1.3 Part 3 Thickness of walls in houses with not more than two floors including the ground floor 7Application 7The use of this part 7Wall types 7Wall construction 7External walls 7Internal load-bearing walls 7Materials 7Maximum loads 8Retained Earth 8Limitations on building geometry 8Lateral support and end restraint 8Buttressing 10Openings and chases in walls 11Interaction of elements 14
1.1.4 Part 4 Proportions for masonry chimneys above the roof surface 19Height to width relationship 19
1.1.5 Part 5 Strip foundations of plain concrete 19Conditions relating to the sub-soil 19Design provisions 19Minimum width of strip foundations 20
Sub-section 2 Design and construction of all building types - codes, standards and references 22
Introduction 22Codes, standards and references 22
Sub-section 3 Recovering of existing roof structures and structural safety of external wall cladding 27
Recovering of existing roof structures 27Structural safety of external wall cladding 27Technical approach 27Codes and standards 28
SECTION 2 DISPROPORTIONATE COLLAPSE 29Codes and standards 29Additional information 29
STANDARDS AND OTHER REFERENCES 30
Building Regulations, 1997Technical Guidance Document A Structure
IntroductionThis document has been published by the Minister for theEnvironment under article 7 of the Building Regulations,1997. It provides guidance in relation to Part A of theSecond Schedule to the Regulations. The documentshould be read in conjunction with the BuildingRegulations, 1997, and other documents published underthese Regulations.
In general, Building Regulations apply to the constructionof new buildings and to extensions and materialalterations to buildings. In addition, certain parts of theRegulations apply to existing buildings where a materialchange of use takes place. Otherwise, BuildingRegulations do not apply to buildings constructed prior to1 June, 1992.
Transitional ArrangementsIn general, this document applies to works, or buildings inwhich a material change of use takes place, where theworks or the change of use commence or takes place, asthe case may be, on or after 1 July, 1998. TechnicalGuidance Document A - Structure, dated 1991, alsoceases to have effect from that date. However, the latterdocument may continue to be used in the case of works,or buildings in which a material change of use takes place -
- where the works or the change of use commence ortakes place, as the case may be, before 1 July, 1998,
- in respect of which a Fire Safety Certificate under theBuilding Control Regulations, 1991 to 1994, has beengranted, where the works or change of usecommence or takes place, as the case may be, notlater than 31 December, 2002.
The GuidanceThe materials, methods of construction, standards andother specifications (including technical specifications)which are referred to in this document are those whichare likely to be suitable for the purposes of theRegulations. Where works are carried out in accordancewith the guidance in this Document, this will, prima facie,indicate compliance with Part A of the Second Schedule tothe Building Regulations. However, the adoption of anapproach other than that outlined in the guidance is notprecluded provided that the relevant requirements of theRegulations are complied with. Those involved in thedesign and construction of a building may be required bythe relevant building control authority to provide suchevidence as is necessary to establish that the requirementsof the Building Regulations are being complied with.
Existing BuildingsIn the case of material alterations or changes of use ofexisting buildings, the adoption without modification ofthe guidance in this document may not, in allcircumstances, be appropriate. In particular, theadherence to guidance, including codes, standards ortechnical specifications, intended for application to new
work may be unduly restrictive or impracticable. Buildingsof architectural or historical interest are especially likelyto give rise to such circumstances. In these situations,alternative approaches based on the principles containedin the document may be more relevant and should beconsidered.
Technical SpecificationsBuilding Regulations are made for specific purposes, e.g. toprovide, in relation to buildings, for the health, safety andwelfare of persons, the conservation of energy and accessfor disabled persons. Technical specifications (includingharmonised European Standards, European TechnicalApprovals, National Standards and Agrment Certificates)are relevant to the extent that they relate to theseconsiderations. Any reference to a technical specificationis a reference to so much of the specification as is relevantin the context in which it arises. Technical specificationsmay also address other aspects not covered by theRegulations.
A reference to a technical specification is to the latestedition (including any amendments, supplements oraddenda) current at the date of publication of thisTechnical Guidance Document. However, if this versionof the technical specification is subsequently revised orupdated by the issuing body, the new version may be usedas a source of guidance provided that it continues toaddress the relevant requirements of the Regulations.
Materials and WorkmanshipUnder Part D of the Second Schedule to the BuildingRegulations, building work to which the Regulations applymust be carried out with proper materials and in aworkmanlike manner. Guidance in relation to compliancewith Part D is contained in Technical Guidance DocumentD.
InterpretationIn this document, a reference to a section, sub-section,part, paragraph or diagram is, unless otherwise stated, areference to a section, sub-section, part, paragraph ordiagram, as the case may be, of this document. Areference to another Technical Guidance Document is areference to the latest edition of a document published bythe Minister for the Environment under article 7 of theBuilding Regulations, 1997. Diagrams are used in thisdocument to illustrate particular aspects of construction -they may not show all the details of construction.
Building Regulations - The Requirement Part A of the Second Schedule to the Building Regulations, 1997, provides as follows:
Loading. A1 (1) A building shall be designed and constructed, with due regard to thetheory and practice of structural engineering, so as to ensure that thecombined dead, imposed and wind loads are sustained and transmitted tothe ground -
(a) safely, and
(b) without causing such deflection or deformation of any part of thebuilding, or such movement of the ground, as will impair the stability ofany part of another building.
(2) In assessing whether a building complies with sub-paragraph (1), regard shallbe had to the imposed loads and wind loads to which it is likely to besubjected in the ordinary course of its use for the purpose for which it isintended.
Ground movement. A2 A building shal