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I am looking to build a paver walkway along the side of my house. I would like to build it with an open graded base as that seems to be the preferred approach nowadays. With that said, I have been to 4 masonry/landscaping supply centers in my area (Long Island to be specific) and the only open graded aggregate offered is a 3/4 inch washed bluestone. From what I gather, this stone is primarily used as a decorative top layer material. Would it still work as a paver base? It is a sandstone. Does that make a big difference? It seems limestone is more common to use for a paver base. Is that correct?

Thank you for your help.

P.S. Each supplier recommended I instead use their 3/4 inch minus RCA.

teachmehow1977
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The only thing that should matter is if it's crushed stone or gravel. Crushed stone is preferred for drainage applications. When you tamp it, it is supposed to interlock and provide a more stable base than gravel of the same size.

If the bluestone you are being offered is decorative, it usually is more expensive. For example, where I live regular crushed stone is about $25 a ton vs $50 per ton for decorative crushed stone. If that's all you can find, it will work the same. But depending on how much you need, it might be worth a trip to a quarry and to ask if they deliver regular 3/4 crushed.

Also, for all I know, open base is not just 3/4 stone, but 3/4 stone with 1/4 stone on top. The whole point is to use a material that easy to move around, ie will give a little bit but will not continue compacting over the years.

Cheery
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Open gradation without compaction is fine for something lightly pressured like a walkway, but the growing preference for open graded crushed stone is based on its high relative density when placed without compaction. It's not the best way. It's the best way to save a buck (or maybe a back). Well graded granular soils like crushed stone (with fines) accept higher levels of compaction, but they require compaction.

Geotextile fabric under the open graded gravel can prevent fines from below mixing into the gravel above to cause settlement. This is a common pattern for heavier stuff like concrete patios. Similarly, for bedding pavers above, you want to use open graded 1/4" rock chips. Sand will slowly trickle into voids in the base layer, goofing up the paver surface. If you can't source 1/4" rock chips, then I suppose a layer of geotextile could again prevent mixing, but given the cost I would consider compacting a well graded base instead.

The bluestone base is fine for a walkway. Your load is probably in the neighborhood of 5 psi which is effectively zero. The important part is rock faces with harsh angles between them. In a surface application like pavers there's inadequate confinement for open graded rounded rocks, where they'll effectively squirt out from under the pavers at walkway edges.

popham
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Working as a landscaper for many years, we always put down a limestone or basalt base, so you are correct.

Todd Kavanagh
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