Delamination is a common problem affecting power-finished concrete floor slabs, although it must be stressed that many thousands of square metres of high-quality concrete floors are built each year without this problem.

Delamination is characterised by thin layers of surface mortar becoming detached from the main body of the slab. The delaminated layer can vary from being paper-thin up to about 8 mm thick, and its area can vary from a centimetre or two across up to several square metres.

Concrete Advice 18 overviews the causes of delamination in concrete floors.