Wall Ties and Restraint Fixings - Masonry First

Wall Ties and Restraint Fixings4© Green Building Store © Irvine Whitlock© Hazle McCormack YoungCAVITY WALL TIE SELECTIONThe selection and spacing of wall ties dependon many factors. These include type ofmasonry to be tied, cavity width, type andheight of building, location, and design life.There are several documents which need to beconsulted and are summarised here.Eurocode 6 – Design of MasonryStructures (BS EN 1996-1-1: 2005)In 2010, Eurocode 6 became the main codefor the design of reinforced and unreinforcedmasonry. Eurocode 6 refers to EN 845-1 forwall ties and sets the density of ties per squaremetre based on the declared value of the tie,the material factor and the design wind load.BS EN 845-1: 2003 Specification forAncillary Components for Masonry –Part 1: Ties, Tension Straps, Hangers andBracketsThis European Standard specifies therequirements for wall ties used forinterconnecting masonry and for connectingmasonry to beams, columns or other partsof the building. Materials, tolerances, tievariations and the requirements for declaredvalues, are all covered in this standard. For tieTypes and qualifying criteria refer to PD 6697:2010.PD 6697: 2010 Recommendations for thedesign of masonry structures to BS EN1996-1-1 and BS EN 1996-2Published Document 6697 contains noncontradictory,complementary informationfrom the withdrawn British Standard BS 5628,which was not included in the BS EN 1996series.It includes recommendations on tie lengths,embedment, density, material and positioning.Masonry-to-masonry ties are classified asTypes 1 to 4; the relevant classification isdetermined by strength, function and use.Minimum declared values for tension andcompression are listed on page 5 for each tieType.Approved Document E: Resistance to thePassage of SoundThis document specifies the acousticperformance requirements of ties suitable foruse in separating walls (Type A) and externalwalls (Type B) of new build dwellings.Type A ties must have a measured dynamicstiffness of