[EMGStoned]

Our newly constructed grey flagstone sidewalk and patio sand would erode after every rain. The contractor replaced the sand a couple of times and then the third time put in a drain and decided to use poly sand (tan). After the sand was wetted, they left.

Once the stones dried, I noticed they had a whitish "film" which made them all look like concrete when before there was variance of color in the stones.

I'm wondering what would have caused the white haze and what can be done about it. I plan to fix it myself. I doubt the contractor will come back again.

Thanks!

[moltenfe]

If you don't get the polymeric sand dust off the surface before wetting it it will create a haze on the suface. This is why most manufacturers have you seal natural stone before using poly sand since once you get it wet the pores in the natural stone will absorb the polymer making the haze VERY difficult to remove (sometimes impossible). You can try to use an acid based natural stone cleaner to remove it. Once you get it off I would seal right away because most polymers can be reactivated by wetting so it may re-haze after a good rain.

[ArtZander]

May inject an additional question; I am getting ready to complete a bluestone walkway and patio and I am planning on using "polymeric stone dust". I would also like to seal the stone to give it that "wet" look. I have read all about the need to "sweep and blow" to avoid a residual haze but I am wondering if the following could mitigate this issue to some degree: Seal the stone first, being careful to not let the sealer drip down the vertical surfaces, then apply the stone dust material using a grout bag.

The joints I am dealing with vary quite a bit; some are a wide as 2 inches, down to 1/4 inch or less.

Any comments regarding my proposed technique would be welcome.