The Brew Cabin

I have a noticed a tremendious amount of whitish grey staining that has discolored my bluestone patio. The patio was just layed in the last 4 days. The material that appears to have caused the bluestone to be discolored could be a couple different culprits. The contractor used polymeric sand to fill the joints. Used Quick-crete bag concrete to fill the joints of the stairs created. They also may have used muratic acid or some type of cleaner that removes paint from brick once the blue stone and polymeric sand had been in place. Let me discribe the results of the appearence of the stone to be of greater help to target the culprit. There are many areas where there is loose sand that appears to have seperated from the polymeric composition. There are areas in the joints where it appears there has been no adhesion between the polymeric sand and the bluestone resulting in small cracks. There is evidence of pitting in the polymeric joint. There is the presence of a hardened white substance that appears to be caked on the stone. The bluestones original color was blueish/greenish/ with streaks of purple and rust. Now the color is washed out grey and white with black streaks and smudges which may have been the purple and rust colors. I spent a tremendouus amount of effort choosing the colors of the stone and I am very disappointed with the result. Is there anything I can have my contractor do next to starting over, specfically to restore the original color of the stone?

I don't have nmuch experience with US-ian bluestone patios, or the construction methods used in your country, but a couple of things strike me about your description.

Firstly, the staining sounds very much like cement staining, and I guess that the contractor used "Muriatic" acid (what we call Hydrochloric acid) in an attempt to get rid of those cement stains. It's not always successful and, on some type of stone, it can have disastrous results.

Secondly, depending on the type/brand of polymeric sand that was used, the acid may well have reacted to dissolve the polymer binder, which is why you have experienced 'pitting'.

All I can suggest is that you call back the contractor and get them to explain what has happened and what they propose to do to ensure you get the patio for which you paid. Any products or companies that I might normally suggest are irrelevant to you in the USA, so you'll have to seek local advice. However, if you can get me a picture or two, I might be able to suggest something.