Masonry Anchors and Ties by the Code
Function of Wall Ties. Typically, wall ties perform three primary functions between a wythe of brick and its backing or another wythe of masonry: 1) provide a connection, 2) transfer lateral loads, 3) permit in-plane movement to accommodate differential movements and, . Wall ties are used in all three types of multiwythe walls (composite, noncomposite and veneer), although some requirements vary slightly depending on the application. The primary differences between these wall systems are in construction details and how the applied loads are assumed to be distributed.
This article will examine code compliant anchors for both masonry walls and for brick veneers. Masonry walls Masonry walls tied to concrete columns: Typically dovetail anchor slots are cast into the concrete column, and anchors are installed into the masonry walls. Channel Slot Systems or various two-piece systems can be used on columns without dovetail slots. Masonry walls tied to steel beams: Various anchors are available depending on the direction of the beams.
Clip-On Column Anchors for beam flanges Perpendicular to the wall custom made due to flange variances. Receptacle Slot Anchor Failure Loads: lbs pullout from mortar bed lbs tension. Masonry to masonry: The code requires that masonry walls consisting of two or more wythes separated by an air space must be connected by wall ties. Nine-gage wire ties are spaced one anchor every 2. The maximum spacing is 36 inches horizontally and 24 inches vertically.
Multiwythe walls what are wall ties used for for composite action and not bonded by headers typically are connected with rectangular ties, Z-Type ties or wire reinforcement. Z-Type wire ties must have the cells grouted solid. These anchors can be used in non-composite walls along with adjustable anchors. The adjustable anchor requirements differ in that the maximum horizontal spacing is reduced to one anchor every 1.
The maximum misalignment of bed joints is 1. Truss-type wall reinforcement is not allowed in non-composite walls, because it restricts in-plane differential movement between wythes. These are to be placed a maximum of 48 inches, and all cells above and below the anchor are to be grouted. Many years ago, some masonry wall ties incorporated a drip bend in the middle of the cavity to allow moisture to migrate to the center and drip down into the cavity.
The drip greatly reduced the anchor strength so any and all anchors with drips have been eliminated for use by the code. The code also limits the cavity to 4. Ties in larger cavities must be designed to resist loads, based on rational analysis taking into account buckling, tension, pullout and load distribution. Brick veneers The backing system what happens if you breach bail conditions exterior veneer must be designed and detailed to resist water penetration.
The exterior sheathing must be covered with a water-resistant membrane, unless the sheathing is water resistant and the joints are sealed. Flashing and weep systems in exterior veneer must resist water penetration into the building interior.
Anchor finishes for masonry and veneer walls: Anchors in all exterior walls and any interior walls exposed to a mean relative humidity exceeding 75 percent must be Hotdip Galvanized After Fabrication or Stainless Steel. Placement in veneer: Both solid and hollow masonry units should have the anchors embedded a minimum of 1. The code allowances below are what makes a good retail store manager veneers that are a maximum of 4.
The minimum airspace allowed is one inch. There are five types of anchors noted in the code: corrugated sheet metal anchors, sheet metal anchors, wire anchors, joint reinforcement, and adjustable anchors. These anchors primarily are used in residential brick veneers and are only allowed with wood-frame backups and a maximum airspace of one inch. They are to be installed with screws or ring-shanked nails. The fastener must be located within?? Corrugated sheet metal anchors are only allowed with wood frame backup.
Sheet metal anchors: These are more commonly seen in commercial applications. Unlike the corrugated sheet metal anchors, these anchors are pre-bent in the factory and provide a much greater compressive strength. The Sheet metal anchors can be used only with wood-frame backups. Sheet Metal Anchors. Wire anchors: These anchors are used in both residential and commercial applications. They must be a minimum of nine-gage and have a two-inch minimum bent end in the veneer. They can be used with wood and masonry backup walls, but not with a concrete backup wall.
Joint reinforcement: Ladder and tab type are both permitted. The minimum wire size is nine-gage with the cross-wires to be a maximum of 16 inches on center.
Provide minimum six-inch lap splices, and ensure that all ends of the longitudinal wires are embedded in mortar at laps. Adjustable anchors: These anchors are permitted with all backups. Adjustable anchors are the only types allowed with steel stud backup and concrete backup, due to deflection of the two walls. As with the masonry walls, veneer adjustable anchors maximum misalignment of bed joints is 1. Single pintle wire ties are permitted with the latest version of the code.
Barrel Screw type for transfer of loads back to structure. Plate Type with Triangle. Brick veneer anchor spacing: For adjustable two-piece anchors, nine-gage wire anchors and gage corrugated sheet-metal anchors; provide one anchor for each 2. For all other anchors, provide one anchor for each 3. Space anchors at a maximum of 32 inches horizontally and 25 inches vertically.
Additional anchors should be placed around openings larger than 16 inches in either dimension. Space them around the opening perimeter at a maximum of three feet on center and within 12 inches of openings. Double Pintle Plate Type. Plate Type with Single Pintle. Correctly specifying, detailing and installing the proper masonry anchoring system for your project will help insure a trouble-free structure for many years to come.
Return to Table of Contents. Skip to content. Masonry Anchors and Ties by the Code. Z-Type and Rectangular Type Wire Ties 4-Wire Joint Reinforcement The adjustable anchor requirements differ in that the maximum horizontal spacing is reduced to one anchor every 1.
Sheet Metal Anchors 3. Barrel Screw type for transfer of loads back to structure Plate Type with Triangle Brick veneer anchor spacing: For adjustable two-piece anchors, nine-gage wire anchors and gage corrugated sheet-metal anchors; provide one anchor for each 2.
By combining the two-inch diameter washer with the brick-tie, the required number of ci fasteners is greatly decreased ci system manufacturers require a minimum inch vertical and horizontal spacing pattern of screws with washers for proper mechanical attachment. Visit www. Chemical Usage and Safety. Managing Stress At Work and Government Affairs. Exercise and Setting Realistic Goals.
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Horizontal Ties to Column and Wall. These ties are used to connect external load bearing elements to the structure certain levels. Therefore, all external loads bearing members such as walls and columns are to be tied or anchored into structure at each roof or floor level horizontally. Type 1 wall ties are a heavy Duty wall tie, designed to be used in high rise, public and commercial buildings. Its innovative shape and design gives it superior strength and must meet requirements stated in DD Part 2. Wall Ties Two Hole. Three Hole. Four Hole Combination Ties. Multi-dimensional ties are used when changing wall thickness. We recommend use of 50% more Round End Ties. Breakback Ties. Breakback ties are vertical break ties designed to break back into .
Hidden from view after construction, wall ties play a vital role in ensuring the stability of a building. Insufficient or poorly installed wall ties can lead to severe structural issues, including damp penetration, masonry cracks or even the collapse of the outer masonry leaf.
Wall ties are manufactured from corrosion and fire resistant materials and include a drip formation to prevent the passage of water to the inner leaf. Over the years, wall tie shapes have evolved tremendously and various materials have been used which are now obsolete e. Prior to , wall ties were usually manufactured from galvanised mild steel.
These ties were expected to last the lifetime of the building, but it has since been recognised that these wall ties can corrode after only years. These days, wall ties are predominantly manufactured from stainless steel which is now readily available commercially and withstands corrosion from water and cement without requiring additional protection.
Modern stainless steel wall ties offer a maintenance-free life and are value-engineered to reduce material content. In standard brick-to-block construction, wall ties are built into the leaves during construction. To ensure wall ties are effective at tying the leaves together they should be pressed down in and then surrounded by fresh mortar and should never be pushed into a pre-built joint.
They should be installed with a slight fall to the outer leaf, not towards the inner leaf as this could provide a path for moisture to cross the cavity. The drip part of the tie should point downward and be positioned near the centre of the open cavity. In other types of cavity wall construction, such as thin-joint blockwork and timber or steel frames , wall ties are typically installed after the inner leaf has been constructed and during the build of the outer leaf of masonry.
Ties must be long enough to span the cavity and provide the minimum embedment in the mortar at both ends, typically mm. For example, a mm long wall tie is suitable for cavities from mm. Cavities are increasingly wider to accommodate thicker insulation depths, as energy efficiency standards improve. Standard wall ties are now available to suit cavity widths from 50mm to mm. The minimum density of cavity wall ties as defined in Eurocode 6 is 2. Typically they are installed at mm horizontal x mm vertical spacing and should be staggered across the wall area to provide an even distribution.
Additional ties should be used at a rate of one per mm height around openings and unbonded edges although blockwork coursing usually means that they are installed at mm vertical spacing. Further information about the position and density of cavity wall ties may be found in PD Standard spacing for cavity brickwork mm x mm centres in a staggered pattern 2. The selection of wall ties depends on many factors. These include the type of masonry to be tied, the cavity width, the type and height of the building and its geographical location.
All factors governing the correct use of wall ties in any given situation are covered by several Eurocodes and Building Regulations, which should be referred and adhered to.
To complement the Building Regulations and Eurocodes, in the UK we have an additional Published Document PD which aids in the selection of wall ties based upon geographic and topographic factors. This means that, in the majority of cases, cavity wall ties may be specified without the involvement of a structural engineer. Tie Types 1 to 4 are used in masonry-to-masonry applications and Tie Types in masonry-to-timber applications.
The Ancon range includes ties for all forms of cavity construction, including the TJ2 tie for thin joint blocks and the CCB range for cellular clay blockwork; three Type 6 timber frame ties ; frame cramps for fixing to concrete, steel or masonry. Use our Cavity Wall Tie Product Selector tool or contact a member of the technical team to aid wall tie selection.
The health, safety and wellbeing of all those who work with us and for us, as well as the general public, is always our No. Leviat has been working closely with both EU notified and UK approved bodies to ensure compliance is achieved at the earliest possible opportunity and we can confirm that we have obtained all relevant certification.
You are here: Home Blog What is a wall tie? Prev Next. What is a wall tie? Tagged in Ancon building envelope cavity wall ties masonry cavity construction. Latest News Construction industry remains open. Manufacturing at Leviat continues through latest national lockdown. Heavy duty tie suitable for most building sizes and types. Not very flexible and not recommended for applications where there is expected to be excessive differential movement between leaves.
Suitable for most sites. However, for relatively tall or unusually shaped buildings in vulnerable areas, the tie provision should be calculated.
Type 2 ties are suitable for use outside the parameters stated e. Contact Ancon for more information. As Type 5 but suitable for developments of between five and seven storeys, being designed to accommodate the increased vertical.