Elenberg Fraser's design defects permitted the cladding that allowed fire to race up the side of the Lacrosse building one night in 2014, lawyers for builder LU Simon argued on Thursday as they closed their case in the $24 million damages claim.

The architect was also negligent by only providing LU Simon with preliminary drawings ahead of the Lacrosse construction that were not sufficiently detailed to show how the specified panels met the requirements of the Building Code of Australia, barrister Peter Murdoch QC said.