1), Belgian Building Research Institute-BBRI,

2) ir., Belgian Building Research Institute-BBRI,

3 ir., Belgian Building Research institute-BBRI,


Evolutions in the design of cavity walls in order to meet the energy regulations, such as thicker insulation, more “efficient” insulation, thickness reduction of the outer leaf, longer ties, use of plastic anchors with ties… are observed. These evolutions can have an influence on the behaviour of the cavity wall.

This paper concerns wall ties. The minimum number of wall ties per unit area can be calculated according to EN 1996-1-1 by the design load and the wall tie resistance (according to EN 845-1). Currently, limited information is available on the tensile and compressive strength of ties.

An experimental test program showed that 5 wall ties per square metre (often taken by default in Belgium) can be insufficient. Further, the results suggest that for the tested ties in a mortar bed the buckling strength was the determining factor, while for ties with a nylon anchor this is the pull-out strength.


Keywords: Design of masonry, EN 845-1, EN 1996-1-1, Eurocode 6