ADU Contractors in Hawaii
Maui Eco Built
185 Alea Place, Makawao, HI 96768
Maui Eco Built offers prefab & custom ADUs, granny flats, and homes on Maui. Panelized construction cuts build time. Structures range from permit-exempt under 200 sq ft to 3,000 sq ft homes. Design, permits & site planning available.
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Elevate Builders Hawaii
1003 Bishop Street, Honolulu, HI 96813
Elevate Builders Hawaii offers home building, renovation, and ADU construction services, including detached ADUs, garage conversions, and in-law suites. Every home includes a 1-Year Limited Warranty for added peace of mind.
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HKC Hawaii
2046 South King Street, Honolulu, HI 96826
Accessory Dwelling Units (ADUs) are a fantastic way to maximize your property’s potential. Whether you’re looking to create a guest house, rental unit, or additional living space for family members, our ADU construction services provide a versatile and comprehensive solution tailored to your needs.
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Lapis Hawaii
1188 Bishop Street, Honolulu, HI 96813
In the heart of Honolulu, a quiet change in residential architecture is happening with Accessory Dwelling Units (ADUs). These well-designed living spaces are more than just extra square footage—they represent the spirit of ‘ohana and provide a practical solution to Hawaii’s housing problems.
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Warrior Construction
590 Farrington Highway, Honolulu, HI 96707
Warrior Construction (license #BC-34373) builds ADUs and ohana units across O'ahu, including detached cottages, garage conversions, and attached units. Costs range from $150K–$600K+. They manage design, permitting, and construction end-to-end.
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Honua Builders
2439 South Kihei Road, Kihei, HI 96753
Honua Builders is a Kihei, Maui-based construction firm offering luxury custom homes, remodels, additions, and ADU construction across Hawai'i. Led by two licensed B General Contractors, they deliver hands-on, high-quality residential and commercial builds.
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HPM Hawaii
380 Kanoelehua Avenue, Hilo, HI 96720
HPM Hawaii offers ADU models statewide, from 416 to 1,672 sq. ft., with pre-approved options for Hawaiʻi Island. They guide homeowners through design, permitting, and construction while navigating each county's unique ADU regulations.
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Coulson Hawaii
P.O. Box 5319, Kaneohe, HI 96744
Coulson Hawaii offers full-service ADU construction on Oahu, managing design, permits & build. Specializing in second-story additions, in-law suites & wheelchair-accessible granny flats to help Hawaii families maximize their property.
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Ali'i Builders
Ali‘i Drive, Kailua-Kona, HI 96740
Ali'i Builders specializes in custom home construction, renovations, and additions in Hawaii. Services include single-family homes, ADUs, granny flats, and multi-generational living spaces. Notable projects include luxury residences at Kūkiʻo Golf and Beach Club.
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Homeowners Design Center
1130 N Nimitz Hwy, Honolulu, HI 96817
Homeowners Design Center in Honolulu, Hawaii, offers ADU design, kitchen & bathroom remodeling, and interior finish products. Family-owned with 40+ years of experience, they serve residential and commercial clients with custom, quality-driven solutions.
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Fabmac Homes
195 Kehalani Village Drive, Wailuku, HI 96793
Fabmac Homes builds custom manufactured homes on Maui with 20+ years experience. Factory-built at Clayton Homes, shipped to Maui in 6–8 months. Features include hurricane-rated construction, energy efficiency, and permanent foundations. Ideal for ADUs, granny flats, or in-law suites.
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Homeworks Construction Inc.
2111 South Beretania Street, Honolulu, HI 96826
Homeworks Construction Inc. is a licensed Oahu contractor with 30 years of experience. Services include custom homes, remodeling, additions, kitchens, bathrooms, lanais, and pools. Their design-build model ensures on-budget, on-schedule results with warranties.
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Kekoa Kamalani LLC
92-1218 Palahia Street, Kapolei, HI 96707
Ward Design Center
91-857 Pohakupuna Road, Kapolei, HI 96706
Ward Design Center is a design-build firm specializing in ADUs, garage conversions, granny flats, JADUs, and in-law suites. They guide homeowners through planning, design, permitting, and construction for functional, custom living spaces.
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Hilweh Builders LLC
45-550 Mahinui Rd., Kaneohe, HI 96744
Hilweh Builders LLC is an Oahu, Hawaii general contractor specializing in ADUs, home additions, and design-build remodeling. Led by Chad Hilweh, they offer integrated architect collaboration, on-budget project management, and Hawaii-specific residential construction expertise.
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Other cities in Hawaii
What you need to know
Building ADUs in Hawaii: Navigating the Aloha State's Unique Landscape
Hawaii is one of the most expensive housing markets in the entire United States, with median home prices consistently ranking among the highest in the nation. The state's geographic isolation, limited land availability, and high cost of living make Accessory Dwelling Units (ADUs) an increasingly popular solution for homeowners looking to maximize their property's value or generate rental income. In response to the housing crisis, Hawaii has actively worked to streamline ADU regulations, making it easier than ever to work with qualified ADU contractors in Hawaii to build these secondary units.
Hawaii's ADU Laws and Regulations
Each county in Hawaii — Honolulu, Maui, Hawaii County, and Kauai — has its own set of zoning rules and permitting requirements for ADUs. In Honolulu, for example, the city allows ADUs on lots zoned for single-family residential use, provided the lot meets minimum size requirements. State law under Hawaii Revised Statutes (HRS) Chapter 46 has pushed counties to ease restrictions and encourage ADU development. Key regulations that experienced ADU contractors must navigate include:
- Minimum lot size requirements that vary by county
- Maximum ADU square footage limits, often capped at 400–800 square feet depending on the county
- Owner-occupancy requirements in certain jurisdictions
- Setback and height restrictions specific to each island's zoning codes
- Compliance with the Hawaii State Building Code, which is based on the International Building Code (IBC)
What to Expect When Hiring ADU Contractors in Hawaii
Working with a licensed ADU contractor in Hawaii is essential due to the complexity of local permitting processes. Contractors must be licensed through the Hawaii Department of Commerce and Consumer Affairs (DCCA), specifically under the Contractors License Board. Homeowners should always verify that their contractor holds a valid General Engineering or General Building contractor license before beginning any project. Experienced local contractors will also be familiar with Hawaii-specific construction challenges, including:
- High humidity and salt air corrosion requiring specialized building materials
- Hurricane-resistant construction standards mandated by state and county codes
- Lava zone classifications on the Big Island that affect insurability and construction methods
- Limited availability and higher costs of building materials due to shipping logistics
The Benefits of Building an ADU in Hawaii
Despite the challenges, investing in an ADU in Hawaii offers significant financial rewards. With the tourism industry driving strong demand for short-term rentals and a persistent housing shortage affecting long-term rental markets, a well-built ADU can generate substantial monthly income. ADU contractors in Hawaii with local expertise can help homeowners design units that comply with county regulations while maximizing livable space and energy efficiency. Features like solar panel integration, rainwater catchment systems, and natural ventilation design are commonly incorporated to reduce utility costs and align with Hawaii's sustainability goals.
Finding the Right ADU Contractor in Hawaii
When searching for the best ADU builder in Hawaii, prioritize contractors with proven experience in your specific county, a strong portfolio of completed ADU projects, and positive client reviews. Request detailed bids, verify licensing through the DCCA, and ensure your contractor pulls all necessary permits. A knowledgeable local contractor will guide you through every step — from initial design and permitting to final inspection — ensuring your ADU project is completed on time, within budget, and fully compliant with Hawaii's unique building requirements.