This paper approaches the issue of performance requirements and construction criteria for masonry enclosure and
infill walls. Vertical building enclosures in European countries include, very often, non-loadbearing masonry
walls, using horizontally hollowed clay bricks. These walls are generally supported and confined by a reinforced
concrete frame structure of columns, beams or slabs. Since these walls are commonly considered to be
non-structural elements, and their influence over the structural response is ignored, their consideration in the
design of structures as well as its linkage to the surrounding structure is often negligent or insufficiently detailed.
In consequence, non-structural elements, as for wall enclosures, are relatively sensitive to drift and acceleration
demands when buildings are subjected to seismic actions. Many international standards and technical documents
alert to the need of acceptability criteria for non-structural walls, however they do not specifically indicate how to
prevent collapse and severe cracking and how to enhance the overall stability for severe seismic loading. In this
paper, appropriate measures are proposed to improve both in-plane and out-of-plane integrity and the performance
behaviour under seismic actions of external leaf of double leaf cavity walls as well as premature disintegration of
the infill walls
