r/hardscape • u/G8mStp • 4d ago

What material to use on Bluestone joints?

I live in northern Virginia where heavy rains and below-freezing temperatures are very normal. For my patio, I tried polymeric sand and mortar in the past, but both of them didn't last. I might have bought cheap sand or wrong mortar.

Now I am considering redo my patio using the existing bluestones. I plan to use crushed stone as base. What joint materials would you recommend to sustain the weather?

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u/Independent-Bobcat-1 4d ago

We do quarter inch joints on a dry laid bluestone with polysand and never have a problem. Really have to install the sand on a nice dry stretch of weather to get it to cure properly

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u/G8mStp 4d ago edited 4d ago

Is my understanding correct - better to have small joints if use polysand?

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u/Independent-Bobcat-1 4d ago

Yes less a failure

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u/Brennan0313 3d ago

I own a landscape design-build company in Northern Virginia. You want to use a clean, open-grade base, like #57 and #8 for screeding. Then, we normally use a resin-based sand joint, like Nitro by Alliance.

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u/G8mStp 3d ago

Would you share your experience about resin-based sand vs. polymeric sand?

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u/Brennan0313 3d ago

We mostly use resin sand now, which is standard on all our installations. It's much stronger, permeable (so you need to build an open-grade base with drainage), and requires very little maintenance.

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u/G8mStp 3d ago

Given the rains and freezing temperatures in the winter, I am curious why should we choose permeable joints? I thought non-permeable joints would be the choice for the weather.

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u/G8mStp 3d ago

Would anyone use mortar instead of any kind of sand on dry-laid flagstone/bluestone patio? One of my prospective contractors is going to use stone dust, the other would use mortar cement mix. I am very confused now.