Building a DADU in North Seattle: Northgate, Lake City and Maple Leaf
By Eric Dexter, Owner & Builder ·
A good share of our Seattle work is north of the ship canal, and the neighborhoods up there have a character that suits backyard cottages: mid-century houses on wider lots, a light-rail station at Northgate, and streets where a second small home reads as perfectly normal. They also have a creek system and a tree canopy that decide where some cottages can go. Here is what is different about building a DADU in Northgate, Lake City, Maple Leaf and their neighbors, with three real builds from the area.
The rules are Seattle's rules
Every one of these neighborhoods is inside city limits, so the Seattle Department of Construction and Inspections reviews the permit under the same citywide code. Since the permanent Neighborhood Residential update took effect on January 21, 2026, that means up to 1,000 sq ft for a unit with two bedrooms or fewer and 1,200 sq ft with three or more, two ADUs per lot, up to 32 feet of height in most Neighborhood Residential zones, and a 5-foot rear setback for the ADU (none where the lot backs onto an alley). The full breakdown is in how big a DADU can be in Seattle. What changes neighborhood to neighborhood is not the code; it is the lots.
What North Seattle lots tend to look like
- Wider, mid-century lots. Much of Lake City, Maple Leaf, Wedgwood and the blocks around Northgate were built out with ramblers and split-levels on lots that leave real room in the back. That room is what makes a two-story, two-bedroom cottage fit without consuming the whole yard.
- Fewer alleys. Many blocks have no alley, so the cottage sits behind the house, the full rear setback applies, and the construction path and utility trench run along the side yard. Side access width is one of the first things we measure — see site work and drainage.
- Big trees. North Seattle has a lot of mature conifers. Under Seattle's tier system a tree 24 inches across or larger is Tier 2 and its protected root zone comes straight out of the buildable area — tree protection rules.
- Creeks and wet ground. Thornton Creek and its tributaries run through Lake City and Northgate. Parcels near them can carry riparian corridor, wetland or flood-prone critical-area overlays that move or shrink the footprint. The SDCI property map shows them — how to check your lot.
The Northgate light-rail effect
The Northgate station matters for two reasons. Under state law, cities may not require off-street parking for an ADU within half a mile of a major transit stop, so lots near the station never have to give up yard to a parking pad — see ADU parking rules. And Seattle's density rules allow more homes on smaller lots within a quarter-mile walk of a major transit stop, which can change the math between two ADUs and a small multiplex — two ADUs or a fourplex. Measure the walking distance from your lot, not the straight line; the code uses walking distance.
Three DIGS builds in the area
Lake City with Garage
A finished two-story detached home with board-and-batten and lap siding, a craftsman entry, an attached garage and a landscaped paver approach. It is what a wide Lake City lot makes possible: Seattle excludes garage space from the counted floor area, so the unit carries a garage without giving up living space.
North Seattle DADU
A full backyard teardown to a finished two-story modern DADU: two-tone Hardie siding, a dark metal shed roof and stained cedar soffits, documented from slab through finishes. Removing the old structure and starting clean put the cottage where the lot wanted it rather than where an old garage happened to be.
An ADU in Northgate
Our most recent Google review comes from a homeowner in Northgate, who described the whole process as taking about eight months. It also mentions that a wiring and insulation issue came up and was fixed at no charge — the kind of thing that happens on real buildings, and the reason we wrote what happens if something goes wrong after the build.
All of these, with full photo sets, are on the projects page and in five real DADU homes.
Planning one north of the canal
Costs here sit in the same Greater Seattle range as elsewhere, roughly $375,000 to $600,000+ all-in, with site conditions deciding where a lot lands — see what a DADU costs. If you are in Northgate, Lake City, Maple Leaf, Wedgwood, Pinehurst or nearby, send us the address. We will check the tree canopy, the creek overlays and the side-yard access before you spend anything on design, and tell you plainly what the lot can carry. More on the city as a whole on our Seattle ADU builder page.
