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Key takeaways
- A gut renovation keeps the foundation, frame and footprint. A rebuild removes them, and zoning, stormwater, energy code and permits treat the two differently.
- Each city draws the line differently. Seattle’s general rule bars only making a nonconformity worse, while Clyde Hill’s 2026 line is $493,000 of project value, which a $750,000 gut passes.
- The planning ranges overlap: for 3,000 square feet, a gut is $900,000 to $1,650,000 and new construction $1,200,000 to $2,700,000 plus demolition.
- The free feasibility check takes about a day. The $1,500 in-depth analysis takes 2 to 3 weeks; ask that it draw both options on one survey.
Short answer: a gut renovation keeps three things a rebuild gives up, the foundation, the footprint and, in some cities, a wall inside today’s setback. Whether that is worth more than a new foundation and a fresh plan depends on your city’s code, your lot and the structure, and I would not trust anyone who says one is cheaper in general. At my planning ranges the two overlap: whole house renovation at $300 to $550 per square foot, new custom home construction at $400 to $900, and demolition typically $20,000 to $50,000.
This is for an owner with a budget of $750,000 or more in Seattle or on the Eastside. The codes below were read at each city’s or agency’s own source on 15 October 2026 unless noted. This is general information, not legal advice; confirm with your city. The wider question is in remodel or tear down and rebuild.
What a gut renovation keeps, and what it still touches
By gut renovation I mean the interior comes out to the studs and joists, the foundation, framing and roof stay, and wiring, plumbing, heating, insulation, windows and finishes are new. The table sets Seattle’s rules for each path side by side.
| Seattle rule | Gut renovation | Teardown and rebuild |
|---|---|---|
| Zoning position | A nonconforming house may be renovated and structurally altered, but not expanded in a way that increases the nonconformity (SMC 23.42.112.A). | May be rebuilt under the same limit, with a licensed surveyor’s survey or documentation the director accepts, and action toward it must start within 12 months of demolition (SMC 23.42.112.B and D). |
| Building code | Remodeling that substantially extends the life of the house may be classed as a substantial alteration: egress, alarms, dwelling unit separation and seismic provisions, which may be met by strengthening foundations and cripple walls (SRC R107.5.1). | Current code throughout, designed in from the start. |
| Energy code | Parts you alter meet the new construction standard. Exposed wall cavities may be filled to a minimum of R-15 (2×4) or R-21 (2×6), and closed cavities are exempt. SDCI notes alterations typically need no energy credits, but unheated space made heated counts as an addition (R503.1 and chapter 5). | The whole house meets the code, with credits: 8.0 for most houses, 9.0 above 5,000 square feet (R406.3). |
| Stormwater | The manual counts a rebuilt house as replaced hard surface when the roof, walls and any floor joists are removed, so a gut that keeps them does not by that route. A structure expanded beyond the existing footing is new (Manual 2.5.2 and 2.5.3). | A house taken down to its foundation counts as replaced hard surface, and one whose foundation is removed as new. Adding or replacing more than 750 square feet brings stormwater review; 5,000 square feet or more of new plus replaced hard surface brings a civil engineer’s drainage report. |
| Trees | SDCI says tree protection varies with tree size, species, zoning and whether construction is proposed on the lot, so ask about any large tree on either path. | The demolition site plan must show every tree with protection. |
| Demolition steps | Stripping interior finishes and non-structural partitions is soft demolition and needs only a construction permit. Check for asbestos first. | A demolition permit, at least 15 days of rat abatement, and an asbestos survey by an AHERA-certified inspector. Housing may be demolished only if it meets a listed condition, and the permit may be held until the building permit issues. |
In Seattle’s general rule, zoning position does not by itself decide it, because a nonconforming house may be rebuilt in its old position; stormwater, energy code, demolition steps and time weigh more. On the Eastside the zoning line can decide it. See Seattle stormwater, the remodel energy code and the new home energy code.
City by city: where a gut ends and what a teardown keeps
These rules matter when the house is nonconforming: legal when built, no longer meeting today’s setbacks, height or coverage. Each city’s full test is in when a remodel counts as a new house; this table adds what a teardown does to the same house.
| City | Where a gut renovation ends the old position | If you tear the house down |
|---|---|---|
| Seattle | SMC 23.42.112 sets no cost or wall count; it must not grow (A). A house inside the shoreline setback may not be substantially improved, defined as 60 percent of market value (of the nonconforming portion, for alterations) in five years (SMC 23.60A.124.D, .936). | Keep the old position if you do not make it worse (SMC 23.42.112.B and D). Inside the shoreline setback, replacement is barred except after a casualty. |
| Bellevue | Proposed in Ordinance 6906, not confirmed adopted: in the LL, SR and LDR-1 districts, three years of alterations worth more than the replacement value of all primary structures bring house and site to full compliance (LUC 20.20.561). | The posted text has no clause keeping the old position after a voluntary teardown. Ask the city, and until it answers plan as if the old position is gone. |
| Kirkland | Structurally altering a roof or exterior wall that misses the height or yard standards means that part must conform (KZC 162.35(7)). On that wording an interior gut that leaves them alone is not named; ask the city to confirm. | No teardown rule confirmed at the code text. |
| Mercer Island | Interior remodeling keeps status at any cost with no exterior alteration. Exterior work ends it past 40 percent of exterior wall length structurally altered in any five years (MICC 19.01.050.C and D). | A teardown removes every wall, so the 40 percent line is passed. Within 25 feet landward of the ordinary high water mark, a legal structure may be completely replaced if the nonconformance does not grow (MICC 19.13.020.A). |
| Medina | Substantial destruction, damage of any origin that would cost 60 percent or more of fair market value to restore, ends it for a house (MMC 16.12.200, 16.36.060.D). The code also defines reconstruction, work above 60 percent of replacement cost counting all phases (16.12.190), but 16.36.060.D applies that test to structures other than houses. Ask the city how it counts a planned remodel. | A house that misses a zoning setback may keep it if the new house stays on the old footprint, any added footprint meets setbacks, and a complete application follows within six months (16.36.060.F.4). |
| Clyde Hill | A project valued over $493,000 in 2026 by the building official, or projects within two years that add up to it, puts every structure and the land under current zoning, drainage and detention rules. | The handout speaks to remodels. A rebuild is new construction, so assume current setbacks, height and coverage. |
| Issaquah | At 75 percent or more of the King County assessed improvement value, review is as new development of the site; below it, Level 1 review, and either way the change must reduce the nonconformity as far as practical (IMC 18.214.070). | A new structure after demolition must conform (IMC 18.214.050). |
Sources: Seattle, Mercer Island and Medina on Municode; Clyde Hill’s 2026 zoning handout; Issaquah’s Ordinance 3013 (effective June 1, 2023; the codified text sat behind a bot check, so later amendments are unchecked). Bellevue is the draft of Ordinance 6906 as posted for council, passage date blank, because its code site showed a bot check. Kirkland’s KZC 162.35 was read on 27 September; its code host showed a bot check on 15 October. No bot check was bypassed.
In Clyde Hill a $750,000 project value passes the line by $257,000 ($750,000 minus $493,000), so the old setback is gone either way; the building official sets the value. In Seattle, and for interior work on Mercer Island, a gut keeps what a rebuild could lose, and that is where a gut earns its place. More on the rebuild side: hiring an architect for a teardown and rebuild.
The money, with unlike things kept apart
My planning ranges: $300 to $550 per square foot for a whole house renovation, $400 to $900 for new custom construction, demolition typically $20,000 to $50,000, and $1.2M to $2.5M all in for a 2,500 square foot custom home. Only a builder’s bid on finished drawings is a price. The two per foot ranges describe different things: a renovation range does not buy a new foundation.
| 3,000 square foot house | Low end | High end |
|---|---|---|
| Gut renovation (3,000 x $300 and 3,000 x $550) | $900,000 | $1,650,000 |
| New construction (3,000 x $400 and 3,000 x $900) | $1,200,000 | $2,700,000 |
| New construction plus demolition at $20,000 to $50,000 | $1,220,000 | $2,750,000 |
The ranges overlap between $400 and $550 per square foot. At $450, 3,000 square feet is $1,350,000 on either path before demolition, so a top-of-range gut can cost more than a bottom-of-range new house. The other way: $750,000 covers about 1,364 to 2,500 square feet of gut renovation ($750,000 / $550 and / $300) and 833 to 1,875 square feet of new construction ($750,000 / $900 and / $400), before demolition. The two per foot ranges are construction only, before design fees, permits, sales tax and contingency; the $1.2M to $2.5M figure includes more, so do not divide it by square feet. See also the million dollar remodel guide.
What a gut keeps is floor area before dollars. Suppose a 40 foot side wall sits 2 feet into the setback, on two stories: 40 x 2 x 2 = 160 square feet of floor a resetting city will not let you put back. Building it elsewhere on the lot, if there is room, is 160 x $350 = $56,000 to 160 x $650 = $104,000 at my additions planning range of $350 to $650 per square foot; with no room, the area is lost. The dimensions are my illustration; yours come from your survey.
The renovation range has no line for a foundation that fails an engineer’s check or framing that cannot carry the plan. Where either turns up, a gut grows toward a rebuild’s scope with the old constraints.
Decision table by situation
Find your situation, then read the last column.
| Situation | Leans gut renovation when | Leans rebuild when | What to check first |
|---|---|---|---|
| Nonconforming house | Your city lets the old position stand (Seattle, or Mercer Island for interior work) and your plan stays under its line. | Your scope passes the line anyway (Clyde Hill over $493,000) or a new structure must conform (Issaquah), so the gut keeps nothing extra. | The survey against today’s setbacks, then your city’s measure. |
| Sloped lot | The foundation and retaining work already carry the house and the plan keeps the footprint. | A geotechnical engineer says the foundation or slope cannot carry the plan. Seattle’s demolition permit on a steep slope site calls for a topographic survey and geotechnical report. | Whether the lot is mapped steep slope, and what a geotechnical engineer says. See sloped lots. |
| Shoreline lot | The work stays out of the part of the house inside the shoreline setback. | The house sits clear of the setback. Inside it, Seattle bars replacement except after a casualty. | Which side of the setback each wall sits on. See the waterfront remodel guide and shoreline exemption. |
| Floor plan fights the structure | The plan you want moves a few bearing walls or beams, which a structural engineer can size. | The plan moves most bearing walls, ceiling heights or stairs, a rebuild in scope. | The plan you want drawn over the existing structure. See when a remodel needs a structural engineer. |
Permit paths and the city’s own review times
Design to permit submission typically takes me 2 to 4 months on either path. After that the clocks differ, and these figures are different kinds of measurement.
| Step | Gut renovation | Rebuild |
|---|---|---|
| Seattle permits | A construction permit; soft demolition needs no demolition permit. | A demolition permit and a new house permit. SDCI says it may hold the demolition permit until the building permit issues; ask when the old house must come down. |
| Seattle review, my figures | About 2 to 3 months for a remodel permit. | 6 to 10 months for a new house. |
| Seattle, SDCI’s published figures | Single family addition or alteration: goal 30 days, current 75th percentile 64 days in City control. | Middle housing, which SDCI says includes single-family homes: goal 60 days, current 75th percentile 117 days. |
| Bellevue, permits completed 12 October 2025 to 12 October 2026 | Structural remodel within the house (BU): 177 permits, median 13 days. If area is added (BR): 169 permits, median 78 days. | New structure (BS): 252 permits, median 175 days. Structure demolition: 48 permits, median 87 days. |
| Signed agreement to issued Seattle permit, my arithmetic | 2 + 2 = 4 to 4 + 3 = 7 months. | 2 + 6 = 8 to 4 + 10 = 14 months. |
SDCI says the total an applicant experiences is roughly twice the days in City control, which would make 64 days about 128 (64 x 2) and 117 about 234 (117 x 2); SDCI publishes no doubled figure. Bellevue’s report does not say how its days are counted, and it refreshes, so my demolition guide, which quoted the 5 October run, differs by a few days. No official construction duration for either path was found, so none is given; get a written schedule from each builder. More cities are in how long a whole house remodel takes.
How to decide it, in order
- Free feasibility check, usually about a day. Ask any architect, me included, to test the house against today’s setbacks, height and coverage and name which of your city’s lines your plan would reach.
- In-depth analysis, $1,500, 2 to 3 weeks. Ask for your city’s wall counts or valuation math, and for the gut and the rebuild drawn side by side on one survey. It earns its cost when the options come out close.
- An engineer’s look. Before you choose a gut, have a structural engineer look at the foundation and framing, the check most likely to move a gut toward a rebuild. Ask who hires and coordinates the engineer.
- A fixed fee. I quote a fixed fee for design and permit, set by project budget and location, about $10,000 to $200,000 depending on scope.
- Construction. Piper Cole administers construction after the permit and does not build.
I have been an architect since 1996, and I am a member of the AIA (since 1992) and NCARB (since 1996). The Carr residence was featured in Above The Lake and Lux magazines.
Before you choose a path
Find out which answer your house points to
Send me the address, the year built and what you want to change. The first feasibility check is free and usually takes about a day.