Beautiful lots, serious site constraints
Sammamish is mostly newer housing on wooded, often sloped parcels, and that combination makes site work a bigger part of the project than homeowners expect. The house itself might be twenty years old and structurally straightforward. The reason your addition needs a geotechnical report is the ground it wants to sit on.
Tree retention is the other recurring theme. Sammamish has taken tree protection seriously for years, and significant trees on your parcel can affect where a structure may go, what has to be replaced and what documentation the city expects. It is entirely workable — but only if it is designed for from the beginning rather than discovered at review.
Neighborhoods we work in
Klahanie · Pine Lake · Beaver Lake · Trossachs · Sahalee · Inglewood Hill · Timberline · Aldarra · Plateau
Permits and inspections in Sammamish
The City of Sammamish reviews and permits work within its limits. Two local factors come up on a large share of projects here: critical areas — steep slopes, wetlands and streams are widespread across the plateau, and work near them can require geotechnical or wetland studies — and tree regulations, which govern removal and retention of significant trees and can require replanting or arborist documentation.
Many neighborhoods also have an active HOA architectural review that runs alongside, and independently of, the city permit. Both have to be satisfied. We design with those constraints in view instead of submitting a plan that has to be reworked.
What we build in Sammamish
- Kitchen remodels opening up 1990s and 2000s plateau floor plans
- Primary bath rebuilds — tiled showers, proper waterproofing, ventilation ducted outdoors
- Additions and bonus-room conversions designed around slope and tree constraints
- Decks and covered patios engineered for grade change
- Whole-house refresh packages: flooring, trim, doors, lighting and paint together
- ADUs and in-law suites where lot, slope and code allow
Sammamish at a glance
- Based in Kirkland — Sammamish is a core service area
- We pull the permits and meet the inspectors
- Written, itemized estimates — no verbal numbers
- Bonded and insured in Washington
- Free walkthrough, written estimate
What Sammamish lets you build in the back yard, in 2026
Washington rewrote the accessory dwelling unit rules statewide, and Sammamish rewrote its code to match. Most of what homeowners here believe about ADUs is two or three years out of date.
| What people ask | Sammamish, 2026 |
|---|---|
| How many you can build | Two per lot — two attached, two detached, or one of each |
| Biggest detached unit | 1,000 sq ft |
| Height | 24 ft for a detached unit |
| Parking | No additional space required when the parcel already has four or more parking spaces, counting the garage and the driveway |
| Owner occupancy | Not required. Washington abolished it statewide under RCW 36.70A.681 — you do not have to live on the lot to have an ADU, and you may rent both units |
| Who issues the permit | City of Sammamish Community Development, Permit Center |
Worth knowing in Sammamish
Detached ADU setbacks are 5 ft at the rear and 5 ft at the sides in every zone. The city's own Handout 310 is dated 2023 and still says one unit, 18 ft and two parking spaces — do not build to it.
Ready-made plans
Sammamish has no pre-approved plan programme.
Source: Sammamish Development Code 21.05.010, current through Ord. O2026-597 (August 2026), plus RCW 36.70A.681. Checked 4 September 2026. Codes in this region are being rewritten faster than any web page keeps up with — we verify your parcel against the code in force on the day we submit, not against a summary.
Four ways to add a unit — a new detached building, the garage, the basement or a suite inside the house — with a calculator that takes your own numbers: see all four and what each returns →
What it costs: a new detached unit on the Eastside runs roughly $325,000 to $550,000 all in, and advertised "starting at" prices leave out $120,000 to $180,000 of site, utility and permit work. Here is the whole number, line by line →
Building in Sammamish: what works in your favor
- Sammamish permits are filed through the regional MyBuildingPermit portal — one system we work in every week.
- Newer housing stock means fewer surprises behind the walls — additions and ADUs here are mostly about smart siting and HOA coordination.
Statewide, Washington law (HB 1337) is on your side in Sammamish: up to two ADUs are allowed on most residential lots, a detached ADU may be up to 24 ft tall with side and rear setbacks of no more than 5 ft, units up to 1,000 sq ft must be permitted, there is no owner-occupancy requirement, and no parking can be required near major transit.
Rules change and every lot is different — we verify your exact address with the city before any design work. This page is information, not legal advice.
Sammamish questions we get asked
Will I need a geotechnical report?
Can I remove trees to make room for an addition?
Does the HOA approval replace the city permit?
Nearby areas we serve
Building in Sammamish? Let's talk.
Tell us about your project — we'll listen, come out, and give you an honest number.
Get a Free EstimateGet a free estimate in Sammamish
Tell us about your project — we'll come out, listen, and give you an honest number.
Call or text(425) 866-3940Email: office@nwhomesremodel.com
Hours: Mon–Fri 8:00 AM – 6:00 PM · Sat by appointment
Based in Kirkland, WA — serving the Eastside and Greater Seattle