It depends.

We don’t plan on renting out the ADU so privacy isn’t a concern. It feeling claustrophobic is though…

Thanks for the responses all. Mark, what are some factors that this depends on?

Also, if there are other options that don’t include a deck e.g, gravel or step down to stone patio, we’re open to that provided it addresses how close the buildings are

It will feel cramped, uneasy, and more exposed than an apartment to have such little space between. At least with an apartment, the design doesn't have units face each other without some larger common space in between them. If you can fit a 30' parking court between them, then maybe that would work. But, you won't have any usable back yard at all.

Relevant section of plans below

We will have a fenced front yard so that will give us another yard

It really depends on the situation. Is the ADU going to block a view? Or is it going to provide more privacy from the neighbors? Do you really need such a grand exit from the primary bedroom? I’m never in my bedroom accept to sleep. Can you move the adu over towards the primary? If you can’t move it, I’d go for more of a courtyard effect than a deck and use lots of landscaping, potted plants, string lights, etc. to make it really private and intimate. Also, ask your architect what you will see from the house since the adu is lower…ie are you going to be looking at the roof ?

Sorry I should clarify that the ADU is existing structure; a garage we are converting. We are pushing out the main house towards the adu to provide more space

Latitude, house height, ADU height, house roof configuration, ADU roof configuration, orientation, window sizes, window locations, house color, ADU color, . . .

I'd create a feature wall on the north face of the adu facing the deck. Maybe a brick wall with planting niches. Or another configuration to be a completely filled plant wall with irrigation.

This could include a water feature to add sound and cool the area. It would make the building face an addition to your deck.

That’s a great idea - thank you!