I am installing a Pavestone pavers patio. I have dug out the area to the depth of around 7 inches, with the plan to have four inches of crushed stone, one inch of sand and then the pavers. I know how to rake the gravel and screed the sand to get a smooth and level surface. However, in order to get off to a good start, is there a trick to determining/ensuring that the hole is the same depth for the entire area and will be the correct depth and elevation?

 

You could drive stakes at the corners, the way batter boards are placed. Pull strings and level them with a string level and measure down to ensure the correct depth. You can check the level of the bottom with a four foot level.

You could install 2x4 along the edge of the excavation and level them. Then use them to strike off the levels with a 2x4 from side to side with an offset cut into it to make it sit at the right height.

Hope this helps.

 

Related to your question, last month I wanted to install a sidewalk using those precast concrete sidewalk slabs (the 24"x30" to be exact).

In searching the internet for any kind of instructions on how best to install them I found a page from a hand-tool maker's website that gives good details on how to install precast concrete sidewalk slab - things like depths and material to use, the layers, and even some tips on the installation steps. I found a lot of the advice on the page quite helpful.

If you are interested, the web site was:

http://www.slabsetters.com/html/installing_slabs.html

In fact, the the page is part of a web site for a hand tool that helps to install those heavy and awkward slabs (hence the web site name of slabsetters).