[sonnydays]

Hi,
My flagstone walkway has polymeric sand between the joints. There are some areas in the joints where the sand is spongee or soft. In one spot, I have some damages from a high heel going through. How hard should polymeric sand become when dry? Thanks

[Stonehenge]

It should get pretty hard. Hard enough that a heel won't push through it. We occasionally see this issue, and when we do, here are the usual culprits:

*There's a good amount of moisture still beneath the sand, preventing it from completely setting up. When that dries up, the sand will harden.
*The project is still very new - sometimes it can take 24 or even 48 hours to completely set up.
*There are issues with the mix in a particular bag of sand. The sand should be pulled and replaced.

Hope that helps.

[sonnydays]

Thanks for the info Stonehenge. It's been 3 weeks so it should have hardened by now. There is even some 'bubbling' in a few areas. Any brand of polymeric sand you recommend for flagstone?

[Stonehenge]

My preference is for those brands that use synthetic binders, not organic ones. We use Techni-Seal and Unilock (which is made by Techniseal), and we rarely (though occasionally) run into issues.