The Brisbane Square Project is a new commercial/office complex in the Brisbane CBD. As part of the construction, honed, grey Sindoor Brown granite and exfoliated black Indian granite have been used as paving. Concerns about staining and marking of the stone in the high-traffic lobby have been raised and questions have been asked about some form of immediate and on-going protection of the granite surface. The application of a sealer has been suggested to provide this protection, possibly in addition to providing an aesthetically desirable “wet-look” which maximizes the desired colouration. However, there are reservations as to the efficacy of most sealers as well as to the cost-benefits associated with sealing and on-going maintenance. Experiences from other granite paving show that routine cleaning and maintenance combined with a maintenance manual that deals specifically with a range of soiling agents and their treatment is the preferred option.
The Indian granites used as paving on the Brisbane Square project have quite low porosities. Sealers do very little in the long term to protect stone from the wide range of contaminants that are available (especially foods and motorcars). Their formulations are much more suited to interior domestic use, i.e. where there is no mechanical wear, UV protection from the sun, and not subject to the effects of fluids carrying a range of dissolved substances.
Given the collective circumstances of the granite paving I would suggest the implementation of a cleaning and maintenance programme that is geared specifically towards your granite paving rather than sealing it with a product of dubious long-term value that has to be reapplied annually, and then OVER any stains or discolouration that might have appeared. Furthermore, any sealer applied to a recently exfoliated surface (that has not yet seen a significant amount of foot traffic) will be removed by the flaking of the granite surface as a consequence to its recent surface treatment. Because of the low porosity of the Indian granites sealers will in effect be topical – meaning that they will be rapidly removed from the surface by abrasion. Additionally, inevitable variations in foot traffic movements will remove the sealer differentially and possibly cause a visual contrast, i.e. tracking.