Good morning Colby,
Your base thickness sounds appropriate for your climate ( this is what we use and we are also located in N. CA.)
I'd go closer to the 3" rather than the 2" for the 3/4" crushed gravel.
If you have access to 3/4" class II base rock that would be preferable to straight gravel. Class II base has some fines mixed into the gravel that aids in binding the base together when it is compacted.

Additional recommendations , : compact the soil below your sub base.
Especially if it is highly organic. Loamy soil to clay like soil is made up of decomposing matter that continues to decompose as it ages.
This is one example of why dry lay patios eventually become uneven and sink , it is one of the reasons why the topsoil layer is commonly removed when laying a patio.

I support the filter fabric method between the compacted gravel base and the sand layer, especially if you use straight gravel which even when it is compacted still has minimal air gaps for the sand to filtrate downwards.

1x6 plastic border will warp out of shape very quickly once a downward and sideward load is pushed against it.
You will need to either augment the 1x6 with additional shear or additional equal loading pressure or use a more appropriate size thickness to support the pressure.

Some methods may include digging a perimeter concrete footing - sort of like a curb that is located below and under the edge of the flagstone.
Or beefing up the edging to a 2x material or countering the side pressing load by edging the edging with rock or cobbles or some other stable + grounded methods.

Mich,

I will take your advice and use the filter fabric. Tamping the soil was not a step I had planned on, but I will go that route as well. I will also call the stone yard and inquire about substituting Class II base rock. Thank you for these good tips.

I am still unsure what to do about the edging. I am toying with a concrete edging like they now put around lawns, but that may be a bit too expensive. But perhaps they can do a thinner edge than what they put around lawns that will bring down the per foot cost.

What is your opinion on using 2x4 plastic edging? the place I ordered my stuff from does not have 2x6 edging. My thinking was I could set the 2x4 edging and then excavate two inches below the bottom of the edging, thus giving me the six inches I need for my base materials and stone. I do remember the stone yard saying the 2x4 edging was difficult to bend, so maybe this will be a problem, as the outline for our patio and walkway has lots of curves.

Colby

Colby, plastic edging is not so nice to see and probably won't be strong enough. Concrete is nice especially if it has a lot of color in it (black is nice 10 lb. to the yard) You can always make form yourself and mix your own concrete but I suspect that those curb in place folks are, all in all, inexpensive.
However why not just mix some concrete for filler on the edge and finish it edge with stone ... if you see the rise (the vertical portion) you could trowel this off nicely and even add colored pebbles as you go...

Colby, doing a similar project next month ourselves (hubby and I). For edging, I would steer away from plastic. Unless you want to edge with brick or stone, try to find steel edging...Home Depot sometimes carries it. Easy to curve for free-form shapes, very durable, and unlike the plastic edging, stays in place (it's held in place by steel stakes).

Well, the 1x4 plastic edging we were going to use is really more like a vinyl edging and seemed pretty sturdy. I also was going to use metal stakes that are custom fit for the edging to secure it. However, after reading everybodyÂs posts, it would seem this is not the way to go. And from an aesthetic point of view, I had never really cared for it anyway, but just didnÂt have a better option readily available. But I had thought that once I landscaped all along the sides of the patio and walkway that the edging would not be so apparent.

I will check on the steel edging, but from an aethetic point of view, IÂm not sure that would be any better.

Using stone or brick sounds the most appealing, IÂm just not sure where to even start. Keep in mind, I am a very inexperienced landscaper and no matter how many google searches I do on flagstone patios, it seems hardly anyone mentions what the different edging options might be.

Appreciate all the comments so far and I am still researching.
Colby

Colby here are a couple more technical options for you.
In the photo I show a steep stone stair case. At the mid point in the stair case (bottom of photo) we have a landing with a dry lay walkway that is bordered by stone. The stone rises above the flagstone 'locking' it and the subbase into place.

Also here is a quick computer sketch - Computer sketching is NOT my forte at all. but I think my thought will come across.
In the option A and B cross sectional views I suggest using a rock border that is under the flagstone vs. the picture that shows the rock border rising above the flagstone.

just a few options to consider.

Michelle
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Michelle,
Thank you very much for the pictures and the explanations! I see perfectly what you are saying.

I think I like the look in the first picture where the edging stone rises above the flagstone. I'm wondering if a concrete footer is used in that first picture.

I hope not, because my initial idea is to get some sort of edging boulder, perhaps around 12". I will trench into the ground 6" or so, and lay about an inch of sand. Then my boulder will sit on top of the layer of sand, protruding about 7" out of the ground. This will leave the top of my flagstone about 1" below the edging boulders (assuming 3" gravel, 1" sand, and 2" flagstone). This seems like it would work, and I would like to avoid a concrete footer, if possible.

I have also found some stone edging on the internet that looks like flat bricks. I'm wondering if that might also work if I trenched down a few inches, laid a bed of sand, and dry-stacked them to an appropriate height.

Am I on the right track here?

And does anyone have suggestions on particular types of edging boulders that they would recommend?

Thanks.
Colby

Good news! I think I have solved my edging problem. I visited the stone yard and found some Arizona Rosa stone that was generally 3-5 inches by 3-5 inches and came in varying lengths. They almost looked like rough cut bricks, when I described it to someone they said it was an Ashlar. In any case it looked ok to build a little dry set retaining wall two rocks high. Since IÂm using Arizona Rosa flagstone, itÂs the perfect match colorwise. Maybe I will need to use mortar, IÂm not sure.

On another note, I had to cancel my entire order at the stone yard because the three pallets of flag they had for me was about 25% 1 ¼ in ch or 1 inch, and I specifically ordereded two inch. There was also a bunch of 1 ½ inch, but I probably would have taken that. But I thought it was a bit ridiculous to have to accept all that thin stuff. I was paying $250 per ton. And they didnÂt seem to want to handpick me the correct pieces, so I just walked away.

I found another stone yard that was willing to special order the flag and promised to get stuff that was all at least 1 ¾ inch or greater. So I will be ordering from them this weekend. The price was only slightly more at $265 per ton. They also had the class II base gravel that Michelle recommended.

So a big thank you to Michelle and everyone else who chimed in. Once I get going I will start posting pictures. :)

looking forward to seeing the finished product and possibly some installation shots as well.
It might be helpful to someone else !

Michelle

Can I ask you what is the sq footage of your patio and how many tons of stone you are getting? I am also very interested in doing my own patio and am trying to get some cost estimates for a 10x12' patio of bluestone or flagstone. Also, I can't see the pictures of the edging, but I agree, this information is hard to come by on the web or in books. If the stones are laid flush with the ground in clay soil, is edging necessary?
Thanks!