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.

After you excavate, I would put down a layer of shale (2b size), then roll a layer of fabric (like Typar), then use shale dust.I'm in cold Pa. with drainage issues & have had success laying flagstone this way.Hope this helps.Just remember, there is lots of ways to end up with the same thing that works.

First, we have a brick home on a concrete slab foundation. Our house is 10 years old. We are having a masonry company put in a flagstone patio for us as a back porch. It is being built on top of a concrete base and will be have mortar between stones. (Please don't get into the whole debate of doing it this way vs doing it on a sand base...I've read it all and we have decided this is best for our situation.) So far, everything looks very good, but am concerned about ONE issue. In one corner (where breakfast nook wall and garage wall hit each other), the flagstone is at the foundation level (where it hits the first brick). From there, it does slope down so that the water will flow away from the house. I just heard in the past (don't remember where) that you shouldn't put things up to the top of the foundation level. On the other hand, I have also heard that the foundation actually is built up some behind the first brick. I can't seem to find info on the net and am scared now that this could be a problem in that one area. Anybody have any knowledge about this type of thing?

What type of soil do you have, how much rain, does it freeze, how deep is the base, load rating for flagstone, how many sq ft, covered or open?