Another question I want to address is whether it is worth using stabilizer in the decomposed granite. This Youtube video argues that stabilizing agents are a bad choice because erosion undoes their benefits.

The same Youtube author argues that weed cloth is a bad idea when installing decomposed granite.

@Yardvaark Great summary thanks.

So I am thinking to do a 2" layer of base rock on the bottom, compressed. Then on top of that I would add three 1.5 inch layers of DG, compressing each layer as we go. I will skip the stabilizer, and I need to think over the stability issue. I have roots growing under this patio that are large and destructive. So soil movement under the base is a real thing for my case.

If you can't cut the roots, can you reroute the walk any? If you can't, try to insulate with grading, so long as it doesn't create other problems. But you may have to fix the walk in the area every few years.

The roots of the redwood tree are already cracking the concrete patio that is closest to the home. I can invest in cutting those roots - to help lessen future damage to the concrete patio - but would have to cut very close to the tree to do that for the new patio. I worry about killing the tree or destabilizing it and having it fall. It's a large enough tree it could destroy a home if it fell.

One of the things that is attractive about DG is that small disturbances could be releveled and compressed as needed. With a permanent install of concrete or pavers. fixing a tree root disturbance becomes very expensive.

With paths near tree roots sometimes you cannot avoid grade change. Exposed roots may become part of the path. Some would play this up, making it a feature.

So I have a path through the side yard that has pavers on either side and crushed 1/4 inch granite partially filling the space between. I wanted to put in decomposed granite between the pavers and level that to just below the paver level. Do I need to remove the 1/4 inch crushed granite? At first, I thought that this granite could replace the 2" of base rock, but now I question whether that would really work as it will constantly shift around under load.

Do I need to remove the 1/4 inch crushed granite and then replace that with base rock, before applying the decomposed granite? While I could remove the 1/4 inch crushed granite, doing so makes the job much more time-consuming, and I need to find a place for the crushed granite.

It looks like you have an adequate path filled to just below the pavers. What's the advantage to you in switching out gravel? Describe the difference between the two finish materials.

@Yardvaark It is not obvious in the photo, but the gravel is actually substantially below the paver level. Of course, I could remedy that just by buying more gravel.

What I expect decomposed granite to do for me is to give me a hard compact surface. This area has a lot of traffic with heavy items on dollies, sacks of garden materials, and is used by landscapers as a prep area for soil mixes. I want this path to feel like a solid walking path. The existing gravel has a very squishy feel to it and rolling a 250 pound load on a dolly over it leaves marks in the path and takes extra effort to pull through.

I'm thinking you could remove a little more than 2" and then blend some sand and clay into the base in order to make it compactable. Then add DG top layer. But test sample the materials first to ensure that they will work.

@Yardvaark Do you have an opinion on whether a base rock layer is needed or desirable under a decomposed granite patio or walkway? Assume you did a 6" dig and had 2" of base rock and then 4" of decomposed granite. Would it be just as effective to dig down 4" and do only the 4" of decomposed granite? When should the use of the base rock layer be mandatory?

I would not think that a base rock layer is needed per se. Here in Florida, patios & walks are typically done with paver base (much like DG) and no larger rock base below. In your case, I'd imagine 4" of DG would work just fine, with no need for a rock base below. Use woven polypropylene fabric below the DG for adding stability and strength. I would consider using base rock when there is going to be vehicular traffic, depending on how much and how heavy

maybe you need crushed limestone

I’d be lost concerned that my neighbors roots are
Causing the patio near your house to crack? You’re trying to do YOUR yard by going around a problem cause by your neighbors tree. I would take care of that before killing yourself trying to work around their roots. You have every right to cut those roots since they’ve definitely invaded your space. And is the potential for the damage to continue and worsen ?

apparently they've got a large tree

Even if on one's property, one can't cut roots to the point that it would be likely to cause a tree to topple over. That would be negligence.

Yard ark then he should talk to the neighbor no? What are the chances those roots will keep growing and doing more damage to his home and or yard hardscape. I’m all for trees but not when they’ll
Ruin something like his home or hardscape. It’s not fair to ask him to sacrifice for a neighbors tree

Well he can do what he wants but you get my point.

but soon or later both of you will have to remove every thing

I'm no expert

It's not fair to sacrifice for a neighbor's tree. But that doesn't justify a negligent action which would cause an imminent danger. One has to seek justice within the law, go to court, if they if they can't acquire a neighbor's cooperation. Cutting anything cosmetic, no problem.

over time they will both have to do something with that tree

When you are installing decomposed granite (DG) with a stabilizer, the usual advice I have seen is to place down 2 inches of DG and then water it and then compress it, allowing at least a day to settle before you do the next layer. If you are not using a stabilizer, then does this apply? Can you just put down 2-inch layers, compress those, and then immediately put down the next 2-inch layer? Do you need to water down each 2-inch layer before compressing?

So I had a contractor look at this patio, and he is telling me that you must use four inches of compressed base rock and only two inches of decomposed granite on top of that. His claim is that no matter how much you compress decomposed granite, it never forms a good hard patio surface on its own.

this area I have no knowledge un