Specification
Features & Applications- Austenitic stainless steel.
- WTS4-200 and WTS4-225 ties meet the requirements of Approved
Use in flat sites in towns and cities where the basic wind speed does not exceed 25 m/s and the altitude is not more than 150m above sea level.
InstallationRecommended Positioning and Density:
- For walls in which both leaves are 90mm or thicker, masonry ties need to be placed at not less than 2.5 per square metre (900mm horizontal x 450mm vertical centres).
- The ties should be evenly distributed throughout the wall area, with the
exception of around openings and should be staggered where possible.
Insulation Board:
- Where insulation board is installed within the cavity and restrained by ties with insulation retaining clips (Simpson Strong-Tie ref. IRC001), it may be
necessary to reduce the horizontal spacing of the ties to 600mm.
- At vertical edges of an opening, unreturned or unbonded edges, and vertical expansion joints - additional ties should be used at a rate of one per 300mm (height) and located not more than 225mm from the edge.
Length of Tie and Embedment:
- Wall ties should be of the correct length to ensure
they are fully embedded in the masonry.
- The tie should have a minimum embedment of 50mm in each leaf, but also allow for site tolerances relating to the cavity width and centring
of the tie.
- The recommended tie lengths will therefore achieve an embedment of between 62.5mm and 75mm.
Sound Resistance:
As stated within the Approved Document E 2003 - Resistance to the Passage of Sound - wall ties used
in external and separating cavity walls have to have a minimum value of dynamic stiffness to reduce the transmission of airborne noise. Ties are separated into Type A and Type B.
Type A: Can be used in separating walls and external walls subject to them also having the required structural capacity. They can be butterfly ties or other ties with a dynamic stiffness of less than 4.8 MN/m3.
Type B: Can only be used in external cavity walls subject to them also having the required structural capacity. They can be butterfly ties or other ties with a dynamic stiffness of less than 113 MN/m3.
