I was thinking laying the gazebo on top because I fear putting the gazebo directly on clay soil would cause it to sink(?).

Here are some drawings I have and a pic:(I could only take a pic from the side.

While it doesn't have to mean that, the word "gazebo" conjures up images of a wooden structure that includes decking and roof. What kind of gazebo structure are you thinking about. What is the floor made of?

Your plan doesn't show the pathway for accessing the gazebo. What/how are you going to do with that?

The back yard looks surrounded on all sides with walls with only two possible paths for rainwater to escape. Taking care of drainage will be critical so I would suggest you make sure the plan for that is well thought out before you build anything.

Maybe it's just me, but I find it very annoying to have an A/C unit very close to seating, where people are trying to converse and hear. It also seems logical to me that a patio, especially in a small yard, would be near to the patio doors, where it's most conveniently accessed and fosters the most efficient use of materials. But then, I would not like a DG as the surface that is so close to the house. A hard surface would be so much less messy. If you're using DG simply as a cost-saving way of creating a patio, I suggest you explore other options. This looks like DIY and I think you could build a small hard surface patio for not all that much more than DG, if you are creative about it.

The major elements of your design -- gazebo/patio & pond -- are placed away from the house, dictating that what planting there will be is placed closer to the house. Is there never going to be a wish to plant things which have the capability of screening above the perimeter wall? In general, when you are trying to figure out where to place elements in a plan, it is easier to use a straight plan view (looking down from above ... "bird's eye" view) than it is to use a perspective drawing. As you become "sold" on a scheme, you can use a perspective view to help understand more what things will look like and how they will affect other things.

You will not be able to use "2-by" lumber as a wood frame for containing DG. Such thin wood will warp and in direct contact with ground, not last very long. Usually, only "4-by" timbers or greater are treated for ground contact.

For a small yard that's a sizable pond. I'm not trying to discourage such a venture, but if you are without pond experience, use caution. There are plenty who've built ponds and later regretted it ... especially if they cut corners on the pond liner, as a pond that leaks is no pond at all. This one is nearly the size of your patio.

I will just be buying a gazebo, a 10x10' structure with metal roof so no floor, probably from Home Depot. I've wracked my brains trying to figure out where to put things in the back. The pond location is where we can view it from inside as well as from the gazebo. I could make it smaller. I just kept reading that it is better to have a bigger one for koi. The yard is rough graded and there are drainage systems in place. I am planning to use mulch or gravel as ground cover and stepping stones leading to the patio/gazebo as we are going for a Japanese garden.

I am planning to plant some bamboo on either side of the yard for privacy since there is a 3-story apartment opposite us.

re: dg - I like the natural look. gravel would be ok as well. I chose that location so dg won't get in the house and we can enjoy looking at the pond from there.

There is a 6 foot distance from wall to pond where I can plant some trees, bushes, etc.

For now I just want to prioritize making a patio so we can hang out. Would it be better to place the patio/gazebo and pond closer to the house and if so, where? Patio/gazebo beside house maybe? But where could I put the pond? This is mind boggling lol.

"This is mind boggling lol."

Ha, I know it can seem like that! If you were a professional coming on scene in order to do this for someone else, at first you'd be collecting information from the client such as the basics you've told us you want (patio, shelter, screening from neighbors, Jap. vibe, etc.) And you'd be collecting information about site conditions. At this point we can see very little of the latter. If you hadn't said anything about it, we wouldn't know there is a large apartment building to screen. Next in the design process is analyzing the site conditions and then, trying to reconcile the client's desires with them. While some things tend to fit in logically consistent ways -- like patios and patio doors -- other things, like ponds, may seem a bit more open ended such that they could be located in a variety of placements. It's usually the case with creating a landscape environment that there are a host of trade-offs. Rarely is it the case that you can have whatever you want wherever you want it. It's more often that favoring one thing means that something must "suffer." One must determine priorities and then attempt a variety schemes in order to satisfy them.

Here, it seems to me like you are complicating the issues by creating a patio space out of DG. I'm no expert in Japanese gardens, but when people are going to create a place for furniture and hanging out on a regular basis, even in Japan, do they not prefer a hard surface? If you made that single change, you could place the patio where it is much more convenient, get it away from the air conditioner and still possibly be able to position the pond in such a way as to be viewable from indoors. At least the issue could be explored. I'm sure there are plenty of hard surface options that would harmonize with the Japanese vibe. Must you see 100% of the pond from indoors in order to be satisfied? If so, it seems like holding steadfastly to this decision is costing you.

I'm not suggesting you have a smaller pond. It's more like, if you have this size pond, be sure to get the high quality liner and not make do with some poly.

I am planning to get the .45 mil liner for the pond. I am VERY open to suggestions as where to locate things, my drawing is just an idea after drawing out different layouts. I could probably use square tile for the patio. I didn't know that dg isn't stable. Having a good view of the pond from inside is just an idea I got when I asked here on the forum. I don't mind it being situated elsewhere but it would be nice to view the pond and feed fish from the gazebo.

So what would you suggest as to location of the pond and gazebo if I were to use a tile surface and how would I go about doing it? How many inches deep do I dig, base material, and could I use metal edging?

The whole yard is 50' long and 19' from the house to the wall. There is a raised bed thingy I use as my tortoise's enclosure to the far left and a small baby tree near it. (Where I drew the raised bed-like things) So pretty much everywhere else is unoccupied.

I'm not familiar with decomposed granite, but if it has sand-like particles, I would advise against it for a patio. We used 1/4 minus crushed gravel in our path and it's a great base, but it's dusty and tracks onto our deck. It has to be topped with a washed gravel.

It's not that DG isn't stable. It's that it's sticks to shoes and is messy as Mayflowers says. If it was right next to the door, there'd be a lot of sand bits tracked into the house, and consequently regret placing it there.

There is not a plan for me to draw over so I'm sketching on the photo. It's not a solution. It's an exploration. I could take a better look if you provide an actual plan. (Again, it will look straight down on the yard as opposed to viewing it from an angle. All you need to show is house footprint and perimeter wall ... both these things to a measured scale. If you draw and photograph it, please photograph it with the camera looking straight at it, not at an angle.)

What you're calling a gazebo I think I'd call a shade structure since it does not include a floor. You need to account for its size and shape when you design the patio. That doesn't mean, however, that it must be an exact match. It's one of those places tradeoffs might happen on account of your tight space situation. If we have a PLAN, we can see what really fits. Also, you might draw the outline of the shade structure next to the plan, to scale, so we can see what needs to be accommodated.

If it was me, I would not home in on patio "tile" blocks just yet.

I drew it out with the measurements as best I could. Don't know if this is what you are referring to. The shade structure we are planning to buy is 10x10' with a metal roof.

The reason why I thought of placing the structure near the wall before is so we could have instant privacy from the 3-story apartment without having to plant along the whole 50 feet but of course it would be nice to have lots of plantings there instead. Perhaps a solid path from the door going to the structure would work for easy access and instant privacy?

It would be cool but challenging to maintain 50 feet of bamboo lol. I've been searching for fast growing coniferous trees that don't take too much space that I can plant along that wall that would go well with the asian design. Would probably need something that grows to 25-30 feet and doesn't take too much space width-wise.

Having a border to retain the dg is commonly necessary , otherwise it will erode away. A border such as pressure treated wood for long straight runs or flexible trex, stone, pavers or metal works well.

An application of class II sub base that is compacted well will provide a stable base. Depending on your soil conditions anywhere between 1 inch to 3 inches is fine.

Base rock is substantially less expensive than decomposed granite in most regions of the country so having thicker layer of baserock is also an economical advantage.

Here in the west we commonly use 3 inches of class II and 1 inch of decomposed granite.

Attached is a photo of a newly constructed garden. It show the trex sweeping borders and a small sitting area , the compacted class II subbase and a pile of dg before it is spread out and compacted over the sub-base.

The artificial turf was also installed over a compacted sub-base .

I agree w/Yardvark's concerns about tracking dg or fine gravel tracking. I also have reservations about a metal gazebo. Here is link to photo (don't know how to make photo just appear) of nice looking very simple shade structure using shade screen or cloth....perhaps the soft sandy ground surface shown here. I wonder how they solved the tracking issue? https://www.houzz.com/photos/blasen-gardens-farmhouse-landscape-san-francisco-phvw-vp~544964  You might also research teahouses for sheltered sitting areas that could further your Japanese vibe.

I'm ok with not using dg. I've been researching other options. That shade structure is very nice but we wouldn't be able to use it when it rains. Tea house would be awesome but I'd probably have it made and would probably be costly. I am thinking a small deck to put the structure on?

That base plan was fine. What I was interested in seeing is if it is possible to create another arrangement that places the pond in view of the inside and allows space for a hard patio immediately adjacent to the patio doors. I think it is possible. It would seem a far preferable arrangement to me than what you were proposing with the remote patio location. Is my drawing the end all/be all solution? Hardly! I'm just saying there are more options than what are currently being explored. If this was mine, I would whip out a piece of tracing paper over the base plan of the back yard and do more exploration. You might want a pond that is semi-circular which uses the perimeter wall as a backdrop (an illusion as they would not actually touch.) But it may fit the space better. Or perhaps there could be a yin-yang thing going on with patio and pond.

Tracking DG is definitely an issue that needs to be considered, as Yardvaark mentioned. Here's a guide we put together on installing DG if you decide to go that direction: https://southwestboulder.com/blog/how-to-install-a-decomposed-granite-pathway

Thanks for the responses, tips, and suggestions, everybody. I guess there's a lot more exploring and researching to be done on my part.

Feel free to return with questions as you work it out.

Here's an example of continuing to explore an idea. One keeps doodling until achieving a solution that fulfills the requirements and that one likes.