One shared wall,
a full second home in Auburn.

The wall you share stops being an ordinary interior partition the second two separate dwellings sit on either side of it. Code wants a rated separation then — usually a one-hour fire assembly running floor to roof deck, the correct gypsum layers, fireblocking, and ideally a sound-rated cavity so your tenant isn't living inside your TV. People don't expect this part. On older homes near downtown and up in the foothill subdivisions we've opened walls expecting plywood and found board sheathing, no fireblocking, and wiring that's cooked through a few decades of Sierra summers. That existing wall almost always needs upgrading to carry the rating. We draw the assembly on the plans, build it to the listed spec, and the City inspector signs off on something real.

Here's a range, then the honesty. A 468 sq ft one-bed attached unit with sensible mid-grade finishes generally lands around $221K to $284K all-in in Auburn. Go bigger — a 742 sq ft two-bed with its own utilities throughout — and you're closer to $309K to $397K. Attached usually pencils a touch under detached per square foot, because you borrow a wall and tap utilities already on that side of the house. Three Auburn things move the number. The ground is granite and decomposed granite, so footings and trenches can hit rock that needs breaking. Hillside lots add retaining walls and stepped foundations. And the fire-zone construction — ember-resistant vents, fire-rated siding and eaves, tempered glazing — is real money we price from the first visit. We test the ground and read the slope early so the quote matches your actual dirt.