Short answer: Piper Cole Architects is based in Kirkland, and I design new custom homes in Sammamish for a fixed fee, about $10,000 to $200,000 depending on budget and location. I offer a free feasibility check in about a day. Before you pay for drawings, an architect should tell you what the code lets a new house be on your lot, what a teardown loses, and what the lake or a slope adds.

This page is for an owner planning a new house in Sammamish, usually a teardown and rebuild, on a large lot or on the lake, with a budget of roughly $2,000,000 to $6,000,000. Piper Cole designs and administers construction on your behalf and does not build. The rules come from the City of Sammamish’s code, pages and forms and from state law, read on 20 October 2026; I mark City, County, district and State. Confirm with the city. For an existing house, see my Sammamish remodel page.

What Sammamish’s code lets a new house be

This is City code, Title 21 of the Sammamish Municipal Code (SMC). My zoning guide has the zone-by-zone tables.

Worked lot A, upland. One acre, 43,560 sq ft, R-1. Floor area cap 21,780 sq ft (43,560 x 0.50). Hardscape cap 13,068 (43,560 x 0.30). At $400 to $900 per sq ft, $2,000,000 buys 2,222 to 5,000 sq ft and $6,000,000 buys 6,667 to 15,000, so the budget reaches its limit before the floor area cap does; hardscape, setbacks, trees and the upper floor cap shape the plan. With 60 significant trees outside critical areas (my assumption), R-1 keeps 30 (60 x 0.50).

A teardown: what happens to the old house

Since June 14, 2025 SMC 21.09.130.C says nonconformance status is forfeited, “which includes demolition of the structure.” I read that to mean a new house meets today’s setbacks, height and hardscape even if the old one sat inside a line, so I compare the new envelope with the old footprint first. Sometimes the answer is to keep the house; see my teardown guide. A lake house has a second text, below.

Demolition is its own city permit. The form asks for a demolition plan (clearing limits, tree protection, septic, fuel tanks, wells), historic resources and critical areas affidavits, and asbestos and lead reports for a house built in 1977 or earlier. Septic removal is reported to King County Public Health and fuel tank removal to the State Department of Ecology.

Under SMC 21.06.045.D.1.j, the impact fee section in effect since 1 July 2026, a replacement house pays no impact fee on the floor area it replaces if a complete building permit is submitted within 12 months of the demolition permit; added floor area is charged. So I time the demolition permit to the drawings.

If the lot touches Lake Sammamish

This is City code too: the Shoreline Master Program, SMC Title 25, approved by the State. It reaches 200 feet landward of the ordinary high water mark (OHWM). The city puts the local OHWM at 28.0 to 28.2 feet (NGVD29) and says a professional may need to set it. Ecology gave final approval to the latest amendment on 7 May 2026, and the city’s summary describes it as updating a reference to the critical areas rules, so the numbers below are the program text in that package.

Source: Title 25 in Ecology’s amendment package (fortress.wa.gov, SammamishLIA2025) and the city’s shoreline page. Where the program and zoning differ, the stricter applies (SMC 25.01.060(4)).

Worked lot B, on the lake. 15,000 sq ft above the water line, 100 feet wide and 150 deep, R-4 (assumed), a house over 4,000 sq ft. Depth: 150 to 25 front yard, 50 shoreline setback = 75 feet. Width at 12 foot average side yards: 100 to 24 = 76; the program’s side rule allows 15 feet in total, so zoning governs. The box is 75 x 76 = 5,700 sq ft. With Reduction 1 (a 35 foot setback) it is 90 x 76 = 6,840, and at the 20 foot floor 105 x 76 = 7,980. Then the caps bite: floor area 7,500 (15,000 x 0.50) and hardscape 6,000 (15,000 x 0.40), tighter than the program’s yard rule, which allows 8,250 (15,000 x 0.55). The strip is 1,500 sq ft (100 x 15). At $400 to $900 per sq ft, 7,500 sq ft is $3,000,000 to $6,750,000. Setback reductions buy site area that the hardscape cap then spends.

A house already on the lake. SMC 25.08.100 allows reconstruction or replacement that does not increase noncompliance, and replacement elsewhere if the city finds less impact on the shoreline. The zoning code says demolition ends nonconforming status. I get the city’s reading of a lake teardown in writing before I design it.

Permits. A house for your own use up to 35 feet above average grade is exempt from the state shoreline substantial development permit (WAC 173-27-040(2)(g)), but the program still applies, the owner carries the burden of proof, and if any part does not qualify the whole needs a permit (SMC 25.08.030). A design outside the program’s dimensions needs a state-issued shoreline variance (25.08.010(3)). See my shoreline exemption guide. A dock is separate: one per lot, up to 480 sq ft overwater for a one-lot dock (25.07.050(2)).

Slopes, streams, trees and drainage

Landslide areas (City). They include slopes of 40 percent or steeper with 10 feet or more of relief (SMC 21.04.040.B). Work in or within 50 feet of one needs a 50 foot buffer from the top and toe, which the city may reduce or remove on a critical areas report with a geotechnical report (SMC 21.03.020, Ordinance O2024-571, effective 1 January 2025). Buildings sit 15 feet back from a buffer edge. Slopes draining to Lake Sammamish may sit in the erosion hazard near sensitive water bodies overlay, whose no-disturbance area, in the 2022 text I read, allows single-family houses on pre-existing separate lots and little else.

Streams (City). Buffers are 150 feet for Type S and F, 75 for Np and 50 for Ns, and where the buffer is not vegetated to the code’s standard it must be densely planted or widened 33 percent (SMC 21.03.020.W.4). Wetland buffers depend on category, so a biologist’s report sets them.

Trees (City). Significant trees are conifers of 8 inches and deciduous trees of 12 inches at breast height (city tree page). A new house in R-1, R-4 or R-6 needs land use approval before any comes down, and no tree comes out before the construction permit issues. Retention is in the table above, and is 50 percent in erosion hazard areas. Each tree removed is replaced by one new tree, mostly native (SMC 21.03.060.J). The 2026 fee schedule lists unlawful removal at $1,500 per inch.

Drainage (City, on a County manual). Sammamish adopted an addendum to the 2021 King County Surface Water Design Manual: 2,000 sq ft or more of new or replaced impervious surface, or 7,000 sq ft of land disturbance, needs at least simplified drainage review. A new house clears that.

How the city reviews a new house, and who else decides

A new house is a building permit through MyBuildingPermit.com. The city’s checklist requires a critical area affidavit, a plan set with an area table, structural calculations, a drainage checklist and analysis, a site protection plan, a traffic concurrency certificate and water and sewer availability certificates. An arborist report, critical area study, geotechnical report and SEPA checklist may be required. The city answers Project Guidance requests within one week.

How long. The city publishes no review time for a new house. Its building page warns that staff transition may reduce service levels, and its 2025 report to the State Department of Commerce has no single-family row. For planning I use permitting at 3 to 6 months for a custom home, a planning range and not a city figure; a slope, critical area or the shoreline can add to it.

What it costs and what changes the schedule

Planning ranges, not quotes. Per square foot is construction only.

The free feasibility check in about a day comes first; the in-depth analysis is $1,500 over 2 to 3 weeks. Surveyor, engineers, arborist and any biologist are separate. From the city’s 2026 fee schedule, before the 15 percent technology fee on each line: demolition permit $261 plus a $513 site bond; tree removal $139; shoreline exemption letter $810; shoreline substantial development, conditional use or variance $8,330 base fee. The building permit is valuation based, and the zoning guide works the impact fees.

You can hire an architect and a builder separately, with the architect administering construction for you, or one company can design and build. I work in the first. Either way, get a written schedule from each builder. See my custom home timeline.

What to ask any architect before you sign

1. Which setback tier and hardscape cap will my house land in, and where does the code say so?
2. How do you count the garage and the upper floors?
3. Does my lot touch the shoreline program, a landslide area, a stream or the erosion overlay?
4. On the lake, where is the OHWM, and which setback reductions will you use?
5. What did the city say in writing about my old house?
6. Is the fee fixed or a percentage of construction cost, and what does it cover?
7. What schedule are you planning on, and what is it based on?
8. Do you administer construction, and do you build? I administer for you and do not build.

How the work runs, in order

I have worked as an architect since 1996, I am an AIA member since 1992 and an NCARB member since 1996, and I take on 20 to 30 projects a year. The Carr residence was featured in Above The Lake and Lux magazines. See my Lake Washington waterfront page.

Questions