Two Chinese granites, (second grade) Shanxi Black and PFGE0010 light grey, salt-and-pepper granite, were selected and specified as the construction stones for the National Police Memorial. Both granite varieties are staining (for different reasons). The black granite paving and panels covering the shards are discolouring due to rust. The “black” concrete shards are becoming very discoloured by white efflorescence due to the quality of the construction. Efflorescence is also emanating from joints between the inscribed black granite plates surrounding the shards. A large proportion of the sanded grout joints of the shards show hairline fracturing which is also causing separation of the granite panels and even lateral displacement. The white granite is discolouring because of high inherent porosity, the effects of sealing and the continuous ingress of water below the tiles.
……It is concluded that the specifications prepared for the construction of the National Police Memorial were deficient in a number of respects, particularly in stone selection (resulting in conspicuous rusting) and in construction methods which did not preclude the entry of water into the shards though the stone panelling (leading to widespread efflorescence) and into the sub-tile stratum beneath the white granite (causing eventual discolouration).
To award a stone contract to a company that is not experienced in the many important facets of stone selection, stone supply, stone use and stone construction is regrettable and should not have happened. The results speak for themselves. Whilst the present contractor might have been somewhat cheaper in his tender than the more experienced stone companies the replacement or rectification costs will undoubtedly be considerably more than the other original tender quotes.
It has also been noticed that little or no independent expertise on natural stone is sought by the authority to assist them in the pre-tender stage and/or in the evaluating/awarding of tenders that have a natural stone component. There are many aspects relevant to any stone construction where specific advice should be provided so that complex situations such as this current one do not arise. Drawn out contractual and legal disputes could be avoided with the appropriate expertise.
The condition of the National Police Memorial presented above is poor and essentially beyond repair. Either the condition of the stonework in the memorial is accepted with its many deficiencies (but ones that will deteriorate further) or it is basically replaced using high quality stone and constructed by professional stonemasons.