Redmond architect: what the city lets your house be

What a Redmond architect can design on your lot is mostly set before the first sketch. In the Neighborhood Residential (NR) zone the city’s table allows a house 38 feet tall, with yards of 10 feet in front, 3 on each interior side and 5 in the rear, caps structures at 50 percent of the lot and impervious surface at 70 percent, and caps the total gross floor area of all structures on a lot with one dwelling unit at 4,500 square feet, garage and below grade floor included, whatever the lot size. On the worked lot below, 8,000 square feet with a 2,600 square foot house, that cap leaves 1,900 square feet of room: a 1,900 square foot addition reaches it and a 2,000 square foot one does not fit, even though it covers only 45 percent of the lot. My first basic feasibility check is free and very quick, usually about a day: send me the address and what you are thinking of building. I design and administer construction; I do not build.

Who this page is for

This page is for an owner or buyer of a house or lot in the City of Redmond, Washington (not Redmond, Oregon) who is choosing an architect for a remodel, an addition or a new house. The sources for this page were read on 9 November 2026. The figures come from adopted ordinance PDFs on redmond.gov: Ordinance 3261 (adopted 2 June 2026), Ordinance 3220 (17 June 2025) and Ordinance 3269 (15 September 2026). These are printed legislation, not the codified Redmond Zoning Code (RZC), and the online code site was not used. The city’s zoning code amendments page lists later changes. Confirm every number with the city’s planner on call. This is general information, not legal advice. Washington’s architect licensing chapter does not reach design work on a residential building of up to and including four dwelling units (RCW 18.08.410(5)), so hiring an architect is your choice. My Redmond zoning guide and Redmond architect page give background; this page works one lot.

What a Redmond home architect checks first

Table 21.08.200.B (Ordinance 3261) and Table 21.08.300.A set the standards for the NR column. Check your parcel’s zone with the city first, because other zones, such as RA-5, calculate density differently (RZC 21.16.300.B).

Limit	NR zone	Source
Front yard	10 feet	Table 21.08.300.A
Side yard, interior	3 feet	Table 21.08.300.A
Side yard, street side	10 feet	Table 21.08.300.A
Rear yard	5 feet	Table 21.08.300.A
Lake Sammamish setback	35 feet	Table 21.08.300.A
Base maximum height	38 feet	Table 21.08.200.B
Lot coverage, structures	50 percent	Table 21.08.200.B
Maximum impervious surface	70 percent	Table 21.08.200.B
Minimum open space	20 percent of total lot area	Table 21.08.200.B
Total gross floor area, all structures on a lot with one dwelling unit	4,500 square feet	Table 21.08.200.C

The notes and measuring rules matter as much as the numbers:

• Floor area. RZC 21.16.200.E counts the area inside the finished wall surface of the exterior walls and says gross floor area includes garages and below grade floor. It excludes stairwells, unroofed areas, roofed areas open on two or more sides and accessory structures under 200 square feet.
• Coverage and impervious surface. Under RZC 21.16.500, lot coverage sums structure footprints in plan view, including decks over 30 inches high and roofed decks, patios and porches, divided by the lot area. Impervious surface sums all impervious surfaces, and note 7 says critical areas, open space and stormwater rules can leave you below the maximum.
• Open space. Ordinance 3269 (15 September 2026) rewrites RZC 21.36.300.C: a residential lot must provide at least 20 percent as outdoor open space, on a single lot a contiguous area that may include yards and unenclosed decks and porches, with no part under 15 feet wide. The ordinance’s own signature block lists publication on 21 September 2026 and an effective date of 26 September 2026.
• Yards. Setbacks are measured from the property line. Improvements under 30 inches above grade, such as decks, patios, walks and driveways, may sit in setbacks; no other structures, accessory structures included, may. Chimneys, porches, bay windows, eaves and similar features may encroach up to 5 feet into front, rear and street side setbacks, but RZC 21.16.200.C.4.a adds that none may extend more than three feet from the nearest property line; ask the planner how that applies to your plan.
• Flexibility. RZC 21.76.070.C.5 allows front, side and rear setbacks in Neighborhood zones to be reduced by up to 20 percent, never the Lake Sammamish setback, so a 3 foot side yard can become 2.4 feet. For an addition to a single family house the city must also find no significant adverse impact on neighbors and special physical circumstances of the lot, so it is a request, not a right.

Height is measured by drawing the smallest rectangle around the building, finding the midpoint of each side, taking the finished grade at each, averaging the four and subtracting that from the highest point. Midpoint grades of 100.0, 101.5, 104.0 and 102.5 feet average (100.0 + 101.5 + 104.0 + 102.5) / 4 = 102.0, so a 38 foot limit reaches 140.0 feet (RZC 21.16.200.A).

Worked lot: an addition on 8,000 square feet

The worked lot is hypothetical, not a real property or a client’s: 80 feet wide and 100 deep, 8,000 square feet, flat, zone NR, no critical area or shoreline. The existing house has two stories and an attached garage: a first floor footprint of 1,500 square feet and a second floor of 1,100, so gross floor area is 2,600 square feet, plus a 100 square foot roofed porch. The driveway is 500 square feet, the walk 150 and an uncovered patio 300, so structures cover 1,500 + 100 = 1,600 square feet (20.0 percent) and impervious surface is 1,500 + 100 + 500 + 150 + 300 = 2,550 square feet (31.9 percent).

Step	Arithmetic	Result
Building envelope inside the yards	(80 minus 3 minus 3) x (100 minus 10 minus 5) = 74 x 85	6,290 sq ft
Structures cap, 50 percent	8,000 x 0.50	4,000 sq ft
Impervious cap, 70 percent	8,000 x 0.70	5,600 sq ft
Outdoor open space, 20 percent	8,000 x 0.20	1,600 sq ft
Floor area room under the 4,500 cap	4,500 minus 2,600	1,900 sq ft

Option	Gross floor area	Structures	Impervious surface
A. Ground floor addition, 700 sq ft	2,600 + 700 = 3,300, under 4,500	1,600 + 700 = 2,300 (28.8 percent)	2,550 + 700 = 3,250 (40.6 percent)
B. Ground floor addition, 1,900 sq ft	2,600 + 1,900 = 4,500, exactly at the cap	1,600 + 1,900 = 3,500 (43.8 percent)	2,550 + 1,900 = 4,450 (55.6 percent)
C. Ground floor addition, 2,000 sq ft	2,600 + 2,000 = 4,600, 100 over the cap	1,600 + 2,000 = 3,600 (45.0 percent)	2,550 + 2,000 = 4,550 (56.9 percent)

On this lot the floor area cap, not coverage or impervious surface, is the first rule you meet: option C fails while sitting inside 50 and 70 percent. A second floor leaves coverage alone but uses floor area at the same rate, so 1,900 square feet is the ceiling for any mix of floors. Open space is the other number the table sets: 1,600 square feet, no part under 15 feet wide. Ask the planner whether it is checked for an addition to an existing house.

What an addition or remodel sets off

One rule matters before drawings start.

• Nonconforming houses. RZC 21.04.5000.I.1 bars altering or expanding a legal nonconforming structure unless it does not increase the degree of nonconformity, or the city approves it through the review procedures. Under I.2 a legal nonconforming structure must come into full compliance when it is altered or expanded and, within any three-year period, either its gross floor area grows by 100 percent or more, or the costs stated on all approved building permit applications equal or exceed the value of the existing structure at the start of that period. If the worked house were a legal nonconforming structure, 100 percent of 2,600 is 2,600 square feet, so option B at 1,900 is 73.1 percent of the first test. The section does not say how the value of the existing structure is measured, so ask the city before you rely on the second test. These sections are printed in Ordinance 3269.

My guide to when a remodel counts as a new house covers Eastside triggers, and the existing conditions guide explains why the existing house matters.

If the house is new

A teardown starts from today’s table, not the old house’s yards. The cap is the same 4,500 square feet for one dwelling unit, and a new two story house on the worked lot could be, for example, a 2,300 square foot first floor that includes a 600 square foot garage and a 2,200 square foot second floor: 2,300 + 2,200 = 4,500. That footprint covers 2,300 / 8,000 = 28.8 percent of the lot and fits the 74 by 85 foot envelope.

RZC 21.20.060.A.1.b, printed in Ordinance 3220, applies the affordable housing requirement to a Neighborhood Residential development of seven or fewer units where one detached house is redeveloped into another, meets the fractional part through a payment in lieu, and says the amounts are published with the city’s fee schedules (Ordinance 3261 keeps it, RZC 21.20.020.B). The schedule was not read and no amount is quoted; ask the city whether an addition triggers it, and see my Redmond permit fees guide. See also my demolition permit guide and Redmond custom home page.

Critical areas, shoreline and trees

RZC 21.64, Critical Areas Regulations, covers streams, wetlands, critical aquifer recharge areas and geologically hazardous areas, including landslide hazard areas and their buffers (RZC 21.64.060). Its thresholds were not read, so none are quoted: ask the city whether your lot touches one. See my sloped lot guide.

Redmond’s shoreline rules cover Lake Sammamish, the Sammamish River, Bear Creek and Evans Creek, and reach at least 200 feet landward of the ordinary high water mark; for Lake Sammamish they also include its associated wetlands and 100 year floodplain, and for Bear and Evans Creeks only where the mean annual flow is 20 cubic feet per second or more (RZC 21.68.020). For Lake Sammamish, RZC 21.68.060.B (an Ecology-hosted copy) sets a waterfront building setback of at least 35 feet for new development and teardowns, which can be reduced to 20 feet if the area is replanted with primarily native vegetation and recorded on title; only structures needed for waterfront access or docks are allowed within the 20 feet. On a hypothetical 150 foot deep lot with the high water mark at the rear line and a 10 foot front yard, 150 minus 35 minus 10 leaves 105 feet for the house, or 120 at the 20 foot setback, before any other rule. The Sammamish River has a 200 foot buffer and a 15 foot building setback. The shoreline tables in Ordinance 2968, Exhibit A (marked unchanged in Ecology’s amended copy) list a 30 foot height limit in the Shoreline Residential environment and a Letter of Shoreline Exemption application for a single family residence. My shoreline exemption guide and Lake Sammamish page cover the state permit.

For trees, the city’s tree removal page and tip sheet say a Tree Removal Permit is required to remove any significant tree, one of at least 6 inches across at 4.5 feet above grade. On a developed single family lot the yearly maximum depends on lot area: up to 2 trees on lots of 10,000 square feet or less, 4 on 10,001 to 20,000, 6 on 20,001 to 30,000 and 8 on 30,001 or more. All new development, single family houses included, must retain a minimum of 35 percent of significant trees. These figures were read on the city’s pages on 9 November 2026; confirm them with the city. A tree code update is not yet adopted; the city’s timeline shows Council action in January to March 2027.

The permit path and review times

The city’s residential permits page says most permits are applied for through its Plan Review Online (PRO) request form, that each application gets a Project Coordinator who tracks it, and that depending on the scope Fire, Land Use and Civil Engineering may also review. The city’s 2025 Outcome Management Report covers 1 January to 31 December 2025 and lists 369 residential permits received, 167 completed and a median of 39 days for those completed. How it counts days was not checked, and it is not a promise for your project. I give no fee figures here; for cost, see my home addition cost guide. The number depends on the drawings.

What to send me

The address or parcel number is enough to start. It helps to add:

• A remodel, an addition or a new house, and the changes you want.
• Any survey, existing drawings or permit history you already have.
• Whether the lot has a slope, a stream, a wetland or the lake nearby.
• Whether you are buying, and when your inspection period ends.

How it works with me

The first basic feasibility check is free and very quick, usually about a day. If you want more, an in depth analysis is $1,500, takes 2 to 3 weeks and goes further than the first check. If you go ahead, my fee for design and permit is fixed and agreed before design starts. Design to permit submission typically takes 2 to 4 months. After the permit I administer construction for you; I do not build.

I have been an architect since 1996, and I am a member of the AIA (since 1992) and NCARB (since 1996).

Questions

How do I choose a Redmond architect for a remodel, an addition or a new house?

Ask for your lot’s numbers before design: the floor area cap, yards, height, coverage, open space, any critical area or shoreline and trees. Ask how the fee is set and who administers construction. My fee is fixed and agreed before design starts, and I administer construction; I do not build. Washington’s architect licensing chapter exempts design work on a residential building of up to and including four dwelling units (RCW 18.08.410(5)), so the choice is yours.

What can I build on my Redmond lot?

In the Neighborhood Residential zone the city’s table sets a 38 foot height, yards of 10 feet front, 3 interior side and 5 rear, 50 percent structures, 70 percent impervious surface, 20 percent open space and a 4,500 square foot gross floor area cap for all structures on a lot with one dwelling unit. On an 8,000 square foot lot that is 4,000 square feet of structures and 5,600 of impervious surface. The figures come from adopted ordinance PDFs, not the codified code, so confirm with the city.

Does the 4,500 square foot limit in Redmond include the garage and basement?

Yes. RZC 21.16.200.E says gross floor area includes garages and below grade floor, and Table 21.08.200.C says below grade floor area counts toward the total. It excludes stairwells, roofed areas open on two or more sides, unroofed areas and accessory structures under 200 square feet. The cap covers all structures on the lot and depends on the number of dwelling units, not the lot size.

How much of my Redmond lot can I cover?

The table caps structures at 50 percent of the lot and impervious surface at 70 percent. Coverage counts footprints in plan view, including decks over 30 inches high and roofed decks, patios and porches. On an 8,000 square foot lot with 1,600 square feet covered and 2,550 impervious, a 700 square foot ground floor addition brings those to 2,300 and 3,250. Critical areas and other rules can lower the maximum.

What does an addition or major remodel set off in Redmond?

For a legal nonconforming house that is altered or expanded, RZC 21.04.5000.I.2 requires full compliance if floor area grows by 100 percent or more, or permit costs equal or exceed the value of the existing structure, within any three-year period. The section does not say how the value is measured. A teardown rebuild is reviewed against today’s table and may bring an affordable housing payment in lieu; the schedule was not read, so ask the city.

How long does a Redmond building permit take?

The city’s 2025 Outcome Management Report lists a median of 39 days for 167 completed residential permits out of 369 received in 2025. How the report counts days was not checked, and your project may differ. Ask the Project Coordinator the city assigns for the current expectation for your scope.

Do I need a permit to remove a tree in Redmond?

The city says a Tree Removal Permit is required to remove a significant tree, 6 inches across at 4.5 feet above grade. On a developed single family lot up to 10,000 square feet, up to 2 trees may be removed per year, and new development must keep at least 35 percent of significant trees. The city’s tip sheet governs; a tree code update is not yet adopted.

What does a home addition cost in Redmond?

It depends on the drawings, so I give no figure on this page; see my home addition cost guide. For the city’s fees, see my Redmond permit fees guide.

What does the feasibility check cost, and do you build?

The first basic feasibility check is free and very quick, usually about a day. An in depth analysis is $1,500 over 2 to 3 weeks. If you go ahead, I quote a fixed fee for design and permit, agreed before design starts. Piper Cole Architects designs and administers construction. We do not build.