Do I requirement to lay a subgrade for a bluestone backyard balcony? In our small backyard, we plan on laying down a roughly...

In our small backyard, we plan on laying down a roughly 15'x15' bluestone porch. Our contractor has given us two option for a subgrade:

1) Gravel dry-well and sand base
2) 12" gravel subgrade and sand underpinning

Given that this is for a low-traffic/weight patio, is the full gravel subgrade really essential or is the sand base sufficient? The soil is a blend of dirt, construction wreckage and clay. We only see minor puddling during heavier rainstorm.

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Answers:    The sand base is merely for leveling the stones, so they fit tightly and snug to the ground. It probably only desires to be 1" or so. The gravel sub base will help out reduce frost heaving contained by the winter so the patio will not gag and loosen. 6" should be sufficient, but more is other better - especially with clay soils. I'm not sure what you niggardly by drywell (typically a drain with a grate), but the veranda should pitch to drain away - into the yard if at all possible.

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