Construction Permit - Addition or Alteration

What Is It?

You need a construction permit to remodel or add onto your building, whether it is a single-family house, multifamily building, or a commercial or industrial building. Learn how to get a building permit. New structures that are accessory to an existing house, such as a backyard cottage, are considered additions.

  • An addition involves changes to the outside of the building, such as adding floor area
  • A remodel (also known as an alteration) is when you make changes to the building’s interior, like moving non-structural walls

Examples of common projects are adding a second floor, creating another living unit in your home, or remodeling a building for a new business. Very simple additions or alterations might qualify for a quicker permit known as a subject-to-field-inspection permit (see this criteria infographic).

If your addition or remodel will create an accessory dwelling unit, we will report that to King County for sewer treatment capacity charges. You will need to acknowledge those capacity charges during your application process.

How Much Does It Cost?

Fees are based on the value of your project. You pay approximately 75 percent of your fee when you submit your plans and the rest when you pick up your permit. Use our fee estimator to estimate how much your permit will cost. We will also charge hourly fees for certain reviews, such as drainage and geotechnical. All fees are subject to an additional technology fee. See our Fee Subtitle for details.

How Long Does It Take?

We try to finish our initial review of simple permit applications in 2-3 weeks and complex permits in 8 weeks.

How long it takes to get the final permit depends on how complex your project is and how many corrections, if any, you need to make.

Due to COVID-19 safety precautions, our counters are closed and permits are not currently being issued in person or on the day of your application. 

If you have questions, please submit them through our online Q&A portal. 

Steps to Get Your Permit

Get your property information. Find property information to help you plan your project.

Determine restrictions to your project. Research our codes to determine building size limits and construction and life / safety requirements.

Research Stormwater Code requirements. We may require a drainage review of your project. You need to determine whether stormwater requirements apply to your project to submit a complete and accurate application. 

Find incentives for your project. Research the City's different incentives that might apply to your project.

Determine if you need a land use permit. If your project is not a single-family building, you might need a Land Use / Master Use Permit. We need 4 to 8 months (or more) to review land use permits, which must be submitted before you submit your construction permit application.

Attend a coaching session. We offer 20 minutes of free video coaching through the Applicant Services Center to answer drainage, land use, geotechnical, or construction permit questions. If you need a longer coaching session, we offer one-hour sessions for a fee.

Start your application. Complete the Building & Land Use Pre-Application online using the Seattle Services Portal. You will need to upload a site plan and a complete legal description for your site.

Request a pre-application site visit. You  need a pre-application site visit if you will disturb more than 750 square feet of land or disturb any land on a site with an environmentally critical area. Request a pre-application site visit online through the Seattle Services Portal. You'll receive an email once we have added the pre-application site visit (PASV) fees to your project. After you have paid the fee, we will perform the inspection.

Request a pre-submittal conference (optional). We recommend pre-submittal conferences for very complex projects, including buildings with unusual structural systems, substantial alterations, or work in environmentally critical areas or shorelines. You will need to pay a minimum conference fee of 1.5 hours of staff time. We might charge additional hourly fees based on the number of City staff attending the conference, and the amount of follow-up time required.

Apply for exemptions. You may need an exemption if your project is located in an environmentally critical area or near the shoreline.

Prepare your plans. Plans should be to scale and easy to read.

Fill out forms.

Coordinate with other agencies. You may need permits or approvals from other agencies. These are the most common agencies you may need to work with for your permit type:

Get your project screened. We screen your application to make sure it is ready to submit. Screening is available through your Seattle Services Portal. You may schedule an appointment without screening if you wish, but we recommend you get your project screened if you haven't submitted many applications. 

Schedule an intake appointment. Schedule an electronic intake appointment through the Seattle Services Portal. You must upload all application documents by 7:00 a.m. on the day of your appointment. You do not need to be onsite during your intake appointment. However, you do need to be available for questions. We may call or email you on your appointment day for more information.

Tip: Submit your completed application early to be eligible for an earlier appointment in case of a cancellation. Once you submit your application, we'll add your project to The Express Lane. This means your application will likely be taken in well ahead of your scheduled appointment. We can usually take in your application within 2-3 weeks after you upload your complete application. For more information, read How Can I Get in the Intake Express Lane?

Pay fees. Approximately 75 percent of your permit fees are due at intake. The fees are calculated based on your project value.

Make corrections and resubmit your plans. Once all of our reviews are done, you will receive an email telling you that corrected and/or additional documents can be uploaded into your portal. Your project may require multiple correction rounds before our reviews are complete.

Pay final fees. We will notify you if you need to pay any final fees before we issue your permit.

Print your permit. We will notify you when we have issued your permit and the documents are available in your Seattle Services Portal. Print the permit and approved plan set.

Display your permit. Place your permit in a visible location on the project site.

Get related permits. You may need to get additional permits or approvals from other departments.

Renew your permit. Your permit is valid for 18 months after the issue date. If your project is taking longer than that, you need to apply for a renewal.

Request an inspection. See the construction inspections page for when to call us and how to schedule your inspection.

Receive your certificate of occupancy. You only need a certificate of occupancy if you have changed the use of, or number of residences in, your building. Single-family and duplex projects never need a certificate of occupancy; you just need a final "approved" inspection for your project. 

Close your permit. Your permit information will be archived in our electronic document management system.

Construction and Inspections

Nathan Torgelson, Director
Address: 700 5th Ave, Suite 2000, Seattle, WA, 98104
Mailing Address: P.O. Box 34019, Seattle, WA, 98124-4019
Phone: (206) 684-8600
Phone Alt: Violation Complaint Line: (206) 615-0808
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SDCI issues land use, construction, and trade permits, conducts construction and housing-related inspections, ensures compliance with our codes, and regulates rental rules. SDCI is committed to an antiracist workplace and to addressing racism through our work in the community.