Permits, Costs, and Timelines

An accessory dwelling or similar secondary home may involve several separate decisions. This section explains how to identify the right approval route, prepare an application, check ordinary permit fees, and interpret published processing times without treating an estimate as a promise.

Start with the property and project

Before relying on a permit checklist or fee, identify the property address or parcel, the authority that serves it, the proposed unit type, and whether the work is new construction, an addition, a conversion, or work on an existing unit. A detached backyard home and an in-house secondary suite can follow different routes even in the same city.

Planning or zoning permission, building approval, fire review, utility approvals, and environmental or heritage consent answer different questions. One approval does not automatically replace the others. A local authority or qualified professional can confirm which checks apply to a particular proposal.

Browse by task

Choose a planning route

• Choose a planning, zoning, or pre-application route.
• Compare approval routes across England, Wales, Scotland, and Northern Ireland.
• Check Aberdeenshire’s route for ancillary accommodation.
• Check appeal options after an English planning refusal or delay.

Prepare and submit an application

• Prepare plans, inspections, and completion documents.
• Use Toronto’s optional building permit application pre-check.
• Follow NYC’s DOB NOW filing path for an ADU.
• Choose the right San Francisco ADU checklist for the project type.
• Check permits for an Edmonton secondary suite.
• Check permits for a Calgary secondary suite.
• Follow Portland’s ADU permit and inspection steps.

Check fees and timelines

• Check ordinary permit and inspection fees.
• Check Cornwall planning fees for an annexe or outbuilding.
• Understand approval processing times.
• Compare official permit timeline measures across selected jurisdictions.
• Understand San Francisco ADU application and permit timelines.

Follow a local permit process

• Track Austin ADU application fees, permit activation, and expiration.
• Follow the Charlotte and Mecklenburg County detached ADU permit sequence.
• Follow Fort Collins’ ADU development-review and permit sequence.
• Prepare a San Diego ADU submittal or use preapproved plans.
• Use Centennial’s required ADU pre-submittal meeting.
• Apply for a Glendale permit-ready ADU plan.
• Convert an existing space to an ADU in Raleigh.
• Apply for an internal ADU in Herriman.
• Prepare Irvine’s ADU application package.
• Use Pasadena’s ADU Standard Plan and check fee reductions.
• Follow Oakland’s ADU planning and building review stages.
• Submit Long Beach ADU plans and check OTC eligibility.
• Apply with a Pleasanton preapproved ADU plan.
• Track Welsh building-control start notices and approval lapse.

Keep the evidence current

Use the official authority responsible for the property and check its current forms, fee schedule, application classification, service standard, and effective dates before filing. Published examples and service targets describe a stated authority and process; they do not establish that a project qualifies, predict its total cost, or guarantee approval or completion.