Can I Build Second Story Addition in Honolulu, HI? (2026)
Find out if you can build a second story addition in Honolulu, HI. Rules, permit requirements, costs, and next steps.
Adding a second story in Honolulu, HI is possible in most zones, subject to height limits and structural permit requirements.
A second story addition is one of the most complex home improvement projects in Honolulu, HI. It requires a full building permit, structural engineering review, and must comply with the height limits for your zoning district. Unlike a ground-floor addition, a second story changes the roofline and structural load path of your entire home, triggering stricter engineering requirements. In Honolulu, zone height limits range from varies feet in R-5 zones — verify your zone before planning.
Second Story Addition Rules in Honolulu
Second Story Addition Rules in Honolulu: Building permit required: Yes — all second story additions require a permit. Example height limit (R-5): varies feet. Structural engineering drawings required. Setbacks apply to the full structure height.
Costs & Fees
Contact the local building department for current permit fees. Budget separately for structural engineering.
Next Steps
Next steps for adding a second story in Honolulu: 1. Hire a structural engineer to assess your existing foundation and framing capacity. 2. Confirm your zone height limit and verify the addition meets all setback requirements. 3. Submit full structural plans and permit application to the local building department. 4. Inspections required at foundation reinforcement, framing, shear panels, and final.
Honolulu Department of Planning and Permitting (DPP)
Phone: (808) 768-8000 · Verified July 6, 2026 · Source
Website: https://www.honolulu.gov/dpp/
Online Permits: https://www.honolulu.gov/dpp/permitting/
Frequently Asked Questions
Can I build an ohana unit (ADU) on my Honolulu property?
Yes. Hawaii Act 232 (2023) requires Honolulu to permit ADUs (called 'ohana dwelling units' locally) by right on single-family lots, with ministerial approval for code-compliant applications. Owner-occupancy requirements were eliminated statewide. The permit process is through Honolulu DPP. Honolulu is known for slower permit processing — plan for 6-12 weeks for plan check.
What is an ohana unit and how does it differ from a California JADU?
An ohana unit is Honolulu's term for an accessory dwelling unit — 'ohana' means family in Hawaiian. Unlike California's JADU (Junior ADU), which is specifically defined in California Government Code and is a California-only concept, Honolulu's ohana unit is a full ADU. Honolulu's ohana unit rules historically required owner-occupancy (now eliminated by Act 232) and were focused on housing extended family. The JADU concept from California does not apply in Hawaii.
Why are short-term rentals so restricted in Honolulu?
Honolulu has some of the strictest STR regulations in the US. A 2019 ordinance severely limited new Transient Vacation Unit (TVU) permits — new TVU permits are generally only available in resort-zoned areas like Waikiki and Ko Olina. Residential neighborhoods are largely closed to new STR applicants. Violations carry fines up to $10,000 per day — among the highest in the nation. This reflects community concerns about housing affordability and neighborhood character in Hawaii.
Does Hawaii have a solar mandate?
Yes — for solar water heating. Hawaii law (HRS Section 196-6.5) requires solar water heating systems on all new single-family residential construction unless a cost-effectiveness waiver is granted. This is one of the few states with a solar mandate. Additionally, Hawaii has some of the highest electricity rates in the US ($0.38+/kWh), making solar PV economically very attractive. Over 25% of Honolulu single-family homes have solar.
Is Honolulu city or county?
Both. The City and County of Honolulu is a consolidated city-county government governing the entire island of Oahu — including urban Honolulu, Waikiki, Pearl City, Kailua, Kaneohe, and all other communities on Oahu. The Honolulu Department of Planning and Permitting (DPP) handles all building permits, zoning, and planning for the entire island.
What is the Special Management Area (SMA) and does it affect my property?
The Special Management Area (SMA) is a coastal zone designation covering properties near Oahu's shoreline, administered under Hawaii's Coastal Zone Management Program. If your property is in the SMA (generally within 100-300 ft of the shoreline), certain development activities require an SMA permit in addition to standard building permits. The SMA is designed to protect Hawaii's coastal resources. Check with Honolulu DPP at honolulu.gov/dpp for SMA boundary information.
Source: Honolulu Department of Planning and Permitting (DPP) — Building Regulations. Last verified April 6, 2026. View source