We have what looks to be a very similar setup. We opted to end our deck at 16', which for us is right at the window on that wall. It is on the smaller side—the original plans called for it to be 20'—but it works for what we need. Shortening it did mean that we didn't do the stairs the way yours are drawn (which was the original plan for the longer deck) and instead stepped down into the yard and have steps that circle the yard around to the garage/basement door. It's not perfect but there were tradeoffs to doing the longer deck and steps, also. One consideration was that we realized we would lose the space where the stairs came up anyway because we couldn't really put seating or a table there. The window at that end is also a bathroom, and we didn't want it looking out right over the deck. Our basement/garage door is fortunately beyond the house because of our particular layout but we did need to connect to it. Our neighbors have the same house and built a deck last year that runs the full length of that area and is also deeper into their yard. (Not sure on their dimensions, but maybe 16' deep x 20' long?) It's also lovely and definitely more spacious, but leaves them with less yard.

I can't speak to the gardening part yet because we still have to build the path and finish the landscaping there so nothing is growing there yet. We did put a planter box on the deck both for screening and because it gets more sun than the shaded yard below. Our neighbors did a full-on arbor and lattice wall along the length of theirs to block the view of/from neighbors. The space under our deck is not well used right now--we have lofty ambitions of building doors there and making it more organized, but one thing I hadn't thought about was that it does get wet, so it doesn't make great storage for much except gardening supplies that are weatherproof. (It's hard to tell in this photo, but we are on a slope so the space under the deck is 5' or so on the downhill side; there are steps down behind the chair on the right.)

This is what ours looked like when it was newly finished--I'll have to get a shot in daylight with the furniture as it is now. The yard extends just out of view another 20' or so to the right, which includes the garage and door to basement/garage. (The chimney poking out is the house next door, for scale, and this photo is taken more or less from the fence line on the other side.) We do have more yard behind the deck than you would in your plan, but abut to apartment buildings so there is a buffer of trees there. Before we did this project, this was a concrete patio with a small porch that was original to the 1915 house--basically a couple of feet on either side of the door. The building behind us already has balconies that look down into our yard, so I think we had less of an expectation of privacy to start since they can already see into our yard. We're also in California, so this outdoor space is used year-round, which informed some of those decisions. (And no snow to contend with!)

Sorry I looked at the plan- we are t really considering a 3’ pinch point at the entrance to this huge kitchen, the range just inside the entrance but ten feet from a sink and the fridge at the furthest corner? This kitchen plan needs a lot of reworking.

Architects are not as a rule good at kitchen design or exterior garden design. I think if a deck is going to be added it needs to be big and I would do a nice 2 or 3 level large deck . I use decks as an extension of my home so lay it out like a home . A dining space , akitchen type space , and a LR space My advice get agood outdoor design specialist and a good independant KD that kitchen is a mess , This type of idea but of course designed for your available space . I love decks when done well thay are great for entertianing and made from low maintenance material are my fave for out door living

Sounds like your kitchen architect is trying to drive your train for you. I feel that s/he is a wolf in sheep’s clothing. The more you will buy, the more money s/he will make.

I’d put the brakes on immediately until you figure out what YOU really need or want.

I personally would never select a deck over a patio. Too much maintenance IMO.

The business of privacy is a big consideration also. I don't want to see in my neighbors yards, and I don't want them to view my yard activities also.

I feel the same as Beverly, I generally prefer patios as they seem more tucked in and natural looking (although sometimes the house & lot demand a deck) - but I would def not want to lose a basement door -

not sure if you have priced the deck? by me they start at $60k

Looking at the plan, and guessing where the current walls are... the plans say new walls and they are exterior so I'm thinking that means new exterior walls. I don't think it would be worth it. All you are getting is some more floor space, and not really much else. In addition to your very valid concerns, also add in the cost of the new siding, roofing, ect to make that bit of bump out work with the rest of your exterior.

Also in the plan.There is a lot of dash-line walls there, to be removed? Has a structural engineer checked in on these plans? An architect can draw up plans, but aren't always a good choice when it comes to making structural changes.

Put that pro on pause for a moment. Maybe we can help. Could you post your current floor plan and let us know what you want out of your rebuild?

Really bad kitchen design with the sink, refrigerator & cooker being miles apart. 101 design mistake with the refrigerator crammed into that corner.

We are in a city surrounded by neighbors on all sides, and the deck at this level have us looking out well over fence level, into their windows

That 'deck' will be a stage, not a cozy outdoor space. I would not feel comfortable using it. And it will block interior views of the garden outside while reducing the garden space. Possibly a violation of set-back rules. You lose the door to the basement.

I would start over with a different designer.

What's in the basement? Do you use that access to the garden? I think I'd be looking for a Plan B.

You have several projects going on simultaneously - enlargement, kitchen design and exterior hardscape/landscape. Each have their own specialists.

Another agreement here with Beverly. Enjoyed our patio for more than 25 years. We had a fairly large “pie-shaped” lot of over 1/3 acre. Also enjoyed gardening so after creating the patio DIY we engaged a landscape designer to create the gardens and recommend plants/placement. Here’s an overall view.

https://youtu.be/H5t9G-Gujqw?si=X1nGCeOubIIJ4ibw

Here are some better photos of ours with furniture, just to give you a sense of what fits in a 10' deep space. Second photo shows how the patio and deck connect and the depth of the yard/proximity of neighbors behind. (This is still the table we used on our old patio; it will eventually be replaced with something a little smaller that fits the space better, but we haven't decided what size/shape yet.) We maybe could have/should have gone a few feet deeper, but because you have to walk around the deck to get to the basement door where the laundry is, I didn't want to make the path too long. The single most helpful thing we did in the design process was a 3D walkthrough of the plan, which is what helped us decide not to do the longer deck with stairs—we really didn't like the feel of the deck or the yard with that layout.

I will say that while everyone's needs are different, I LOVE having a level out space right outside our kitchen. We use it far more than I imagined we would (e.g., eating meals out there almost daily). Before we built this, we had stairs that went down to a patio in the same location as the new patio and we rarely used it. We also recently hosted one of our first parties since completing this space and one interesting piece was that everyone stayed on the deck and just moved between there and the house—I couldn't seem to shoo people down to the patio even though it's just a few steps. (Next time we will put a table with some of the food and drinks there to encourage people to continue down the steps, and I'm thinking of adding a small firepit—there are also more chairs outside the photo frame.) A patio that was level out was prohibitively expensive in our case because of the slope of the yard—we did get quotes for that too but it was far more costly because of the leveling and retaining wall (and associated structural engineering) that were needed. The deck just needed load calculations. YMMV on setback requirements, but our city requires very minimal setbacks since we live in an urban area. Worth checking your local code to confirm, though.