No, you usually do not need a building permit to replace windows in Portland, as long as the new window goes into the same opening and no framing changes. That is not just a Portland rule. Oregon has one building code for the whole state, and it exempts door and window replacements unless a structural member is changed. Making an opening bigger or cutting a new one does need a permit. Across the river it varies: the City of Vancouver and Battle Ground both exempt same-size windows, but unincorporated Clark County requires a permit to replace any window, even the same size. We checked the official pages of 19 cities and counties to find out where the line sits.
Replacing windows and not sure about the rules?
We quote one window or the whole house, and the written quote names the exact Milgard series and glass for every opening.
Licensed, bonded & insured · Milgard-certified · 20+ years in the Portland area · Flexible financing
Check your own house in 20 seconds
Answer two or three questions and get the answer for your address, based on the official rules we checked.
1. Where is the house?
2. What are you doing?
What we found, city by city
On October 29, 2026 we opened the official building department page, or the adopted code, for every city and county in the Portland metro and Clark County where we install windows. Where a city page says nothing about windows, we say so. In Oregon that gap is filled by the state code, because state law makes the building code uniform in every city.
| Where | Same-size replacement | Bigger or new opening |
|---|---|---|
| Oregon, statewide code | No permit, unless a structural member changes | Permit |
| Portland | No permit (no header change, clear opening not smaller) | Permit |
| Gresham | No permit, where no structural member is changed | Permit |
| Troutdale | No permit, same size or like for like | Permit |
| Oregon City | No permit for homes | Permit if the opening is enlarged |
| Tigard | No permit, where no structural member is changed | Permit |
| Lake Oswego | Points to the state exemption list | Permit |
| Beaverton, Hillsboro, Milwaukie, Happy Valley, West Linn, Tualatin | City page silent, state rule applies | Permit under the state rule |
| Unincorporated Multnomah County | Handled by Portland, Gresham or Troutdale | Same as that city |
| Unincorporated Washington and Clackamas counties | County page silent, state rule applies | Permit under the state rule |
| Battle Ground, WA | No permit ("window replacement, same size") | Permit |
| Camas, WA | Permit, but like-for-like needs no plans and is usually issued the same day | Permit with plan review |
| Unincorporated Clark County, WA | Permit required, even like for like (an RSW permit) | Permit |
| Vancouver, WA | No permit (exempt in the city code) | Permit |
About Vancouver: the city's residential permit page does not mention windows, which is why a lot of websites get this one wrong. The answer is in the city code itself. Vancouver Municipal Code 17.08.090 lists "replacement of window and door assemblies utilizing existing framed openings and not requiring fire resistive rating in one- and two-family units" as work exempt from a building permit. Land use rules can still apply in some areas.
Why Oregon is simpler than you might think
Oregon law says the state building code is "applicable and uniform throughout this state and in all municipalities," and a city cannot add different requirements without the state's approval. So when a Beaverton or Hillsboro page says nothing about windows, the state exemption still applies there. The Oregon Residential Specialty Code lists "door and window replacements" as work that needs no permit, unless a structural member is changed or the window has to be fire-rated.
Oregon also just adopted a new residential code. The 2026 Oregon Residential Specialty Code, based on the 2024 International Residential Code, took effect on October 1, 2026, with a six-month phase-in for the construction chapters. It becomes mandatory on April 1, 2027. Until then, builders may use either the 2023 or the 2026 technical chapters.
What still applies without a permit
No permit does not mean no rules. Oregon's Building Codes Division has a binding statewide interpretation on exactly this question, number 92-21, "Replacement of Existing Glazing." It says that whether or not the opening changes, the new window has to meet today's code for two things:
- Energy. In Oregon, new windows in an existing house must have a U-factor of 0.27 or lower. In Washington the limit is 0.30. Portland's own windows page still lists 0.30, but the state interpretation sets 0.27, and that is the number we install to on the Oregon side.
- Safety glass. Glass in hazardous spots has to be tempered or laminated, even when you are only swapping the window. See the table below.
Where a replacement window needs safety glass
| Spot | Why it matters |
|---|---|
| Within 24 inches of a door edge | People push off or fall against glass next to a door |
| In or next to a sliding glass door or French door | Doors get bumped and slammed |
| Around a tub or shower | Wet, slippery floors and bare feet |
| Wet areas within 60 inches of the water | Same reason, for windows near a tub or pool |
| Beside stairs, landings and ramps | A trip on the stairs can end in the glass |
Those spots come from the hazardous-locations rule in the residential code, section R308.4, as summarized by Clackamas County. There are exceptions based on sizes and heights. A safety-glass window costs more than a standard one, which is one reason two quotes for the same house can differ.
Bedroom windows and the escape rule
A bedroom window has to be big enough to climb out of in a fire. Replacing an old one does not force you to rebuild the wall to today's size rules, if you do it right. In Oregon, a same-size window with an equal or greater net clear opening, and no change to the framing, does not trigger the current escape-opening requirements. In Washington, the replacement must be the manufacturer's largest standard size window that fits the existing frame or rough opening, in the same operating style or one that opens as much or more. Either way, the trap is a new frame that is thicker than the old one and shrinks the clear opening. If the opening is enlarged, the window has to meet the full current rule: 5.7 square feet of clear opening, 24 inches high, 20 inches wide, and a sill no higher than 44 inches.
This is one reason we usually do a full-frame tear-out instead of an insert. About 8 in 10 of our Portland window jobs are full-frame, which keeps the most glass and clear opening. Our guide to full frame vs insert windows explains the difference.
The exception that catches Portland homeowners: historic districts
A permit is one question. Zoning is another. If your house is a historic resource, new windows can need historic resource review even when no building permit is required. Portland lists 17 historic districts, including Irvington, Ladd's Addition, the Alphabet district, King's Hill, South Portland and East Portland / Grand Avenue, plus 6 conservation districts: Eliot, Kenton, Mississippi, Piedmont, Russell and Woodlawn. Individually listed landmarks count too, wherever they are. Portland's zoning code exempts window replacement only in narrow cases, and only for wood, metal-clad wood or fiberglass windows set exactly in the existing openings. New vinyl windows on a historic resource are never on the exempt list. Check Portland's map before you order, not after. Oregon City has its own historic window policy, with a 50 dollar fee if a project goes to its Historic Review Board.
If you own an older home with original wood windows, our double hung windows in Portland page covers the historic rules and the restore-or-replace question in more detail.
Quick checklist before you replace windows
- Same size, no framing change? In Oregon, the City of Vancouver and Battle Ground, no permit. In unincorporated Clark County, get the RSW permit. In Camas, expect a same-day permit.
- Making a window bigger, smaller or adding a new one? Plan on a building permit everywhere.
- Bedroom window? Make sure the new clear opening is not smaller than the old one.
- Glass near a door, tub, stairs or the floor? It must be safety glass.
- Historic district? Check for historic resource review before you order, and know that vinyl is not exempt in Portland.
- Ask your installer for the U-factor of every window: 0.27 or lower in Oregon, 0.30 or lower in Washington.
More guides for the same decision: how to choose a window replacement company in Portland, based on 313 bad reviews.
And what still pays for new windows in 2026: our window rebates guide for Portland and Vancouver.
Ready to price it out? Start with our Portland window installation page.
In Clark County? See window replacement in Vancouver, WA.
Frequently Asked Questions
Do I need a permit to replace windows in Vancouver, WA?
Not inside the City of Vancouver, if the new windows go into the existing framed openings. The city code lists that as work exempt from a building permit. Outside the city it varies: unincorporated Clark County requires an RSW permit even for same-size windows, Battle Ground needs none, and Camas issues like-for-like window permits, usually the same day.
Do I need a permit to make a window bigger in Portland?
Yes. Widening a window or adding a new one changes the framing, so it needs a building permit in Portland and everywhere else in Oregon. The bigger window also has to meet today's escape-opening rules if it is in a bedroom.
Does a replacement bedroom window have to meet egress rules?
Not the full current size rules, if it goes into the same opening without changing the framing and does not shrink the clear opening. In Oregon that is set by the state's binding interpretation 92-21. In Washington the replacement must be the largest standard size that fits the existing opening.
Do I need a permit for storm windows in Portland?
No. Portland lists installing or removing storm windows as work that does not need a permit.
Sources
- City of Portland, Adding Windows or Replacing Windows
- Oregon Building Codes Division, Statewide Code Interpretation 92-21, Replacement of Existing Glazing
- Oregon Building Codes Division, 2026 ORSC Chapter 1 (R105.2 work exempt from permit)
- Oregon Building Codes Division, notice of 2026 ORSC adoption
- ORS 455.040, state building code uniform in all municipalities
- City of Gresham, projects that do not require permits
- City of Troutdale, permit requirements
- City of Tigard, when you need a permit
- City of Lake Oswego, residential permit exemptions
- City of Battle Ground, residential building permits
- City of Camas, building FAQs
- Vancouver Municipal Code 17.08.090, permits and exempted work
- City of Portland, historic and conservation districts
- Clackamas County, residential code summary (safety glazing, escape openings)
- Washington WAC 51-51-4502, replacement windows
- Washington WAC 51-11R-50300, replacement fenestration energy rule
- Portland Zoning Code 33.445, Historic Resource Overlay Zone
Gorilla Works proudly serves Portland, Gresham, Beaverton, Hillsboro, Tigard, Lake Oswego, Happy Valley, Milwaukie, Troutdale, Vancouver WA, and Camas WA. Call (971) 343-4964 or request window installation.
