How Much Does It Cost To Build an ADU in Halifax?

Written by

hgcadmin

Published on

December 13, 2025

The cost to build an ADU (Accessory Dwelling Unit) in Halifax ranges between $250,000 and $350,000+, with larger or more premium builds reaching the higher end of that range. Pricing varies based on factors such as unit size, construction complexity, material selections, finish level, site conditions, and included amenities. Smaller, more straightforward ADUs can sometimes be built for $150,000 to $200,000, while fully custom, high-end units may exceed $500,000. Understanding how these variables affect cost allows you to set a realistic budget and make informed decisions throughout the project.

What Is an ADU in Halifax

In Halifax, an ADU - also referred to as a garden suite, backyard suite, or secondary dwelling - is a self-contained residential unit built on the same lot as a primary home. These units are commonly used for rental income, multi-generational living, or private living and work spaces. ADUs must comply with the Nova Scotia Building Code and Halifax zoning bylaws, which regulate factors such as size, height, setbacks, and overall design.

Average Cost Ranges for ADUs in Halifax

Build Tier	Cost Range	Description
Budget Builds	$150,000 - $200,000	Smaller ADUs (300 - 450 sq ft) using prefabricated designs or simplified construction. Standard finishes and basic amenities keep costs low, ideal for functional housing without extensive customization.
Mid-Range Builds	$250,000 - $300,000	Typically 450 - 550 sq ft with efficient layouts, better finishes, and higher-quality materials. Often custom-built with features like upgraded kitchens, full bathrooms, and improved energy efficiency.
Luxury Builds	$350,000 - $500,000+	Larger ADUs (600 - 1,000+ sq ft) with premium finishes, smart home features, and custom architecture. May include multiple bedrooms, spacious kitchens, high-end bathrooms, and advanced energy systems like solar power or radiant heating.

Key Factors That Influence ADU Costs

Size and Layout

The size of your ADU is one of the biggest cost drivers. Larger units require more materials, more labour, and often higher permitting and servicing costs.

Small ADUs (300–450 sq ft): More efficient and budget-friendly, well suited for single occupants or couples.
Mid-sized ADUs (450–550 sq ft): A balance of comfort and cost, ideal for long-term living.
Large ADUs (600–1,000+ sq ft): Comfortable for small families, but significantly more expensive due to structural complexity and higher material and labour demands.

Building Materials

Material selection affects both the upfront construction cost and long-term maintenance.

Budget-conscious options: Vinyl siding, laminate countertops, standard plumbing fixtures.
Premium options: Cedar siding, quartz countertops, hardwood flooring, triple-pane windows.
Eco-friendly materials such as bamboo flooring, reclaimed wood, and high-performance insulation can increase initial costs but may reduce long-term energy and maintenance expenses.

Site Conditions

Site-specific factors can add substantial cost before construction even begins. Grading, soil conditions, tree protection requirements, and access for construction equipment can add $20,000 to $60,000+ to the overall budget. Narrow lots or properties with limited access or significant landscaping often require additional preparation and coordination.

Amenities and Features

The level of finishes and features you choose can dramatically shift the final price.

Essential features: Compact kitchen, full bathroom, standard appliances, and basic storage.
Luxury upgrades: Smart home systems, high-end appliances, spa-style bathrooms, and custom cabinetry.
Specialized built-ins such as Murphy beds or integrated storage can improve functionality in smaller ADUs but will increase overall costs.

ADU Cost Breakdown by Component

Component	Cost Range
Site prep & foundation	$20,000 - $50,000
Framing & structure	$40,000 - $80,000
Roofing & exterior	$15,000 - $40,000
Plumbing & electrical	$20,000 - $50,000
Interior finishes	$30,000 - $100,000+
Appliances & amenities	$10,000 - $50,000+
Permits & fees	$1,500 - $2,000+

Building vs Buying an ADU

Buying a Pre-Built or Prefab ADU

Pre-built or prefab ADUs can be an appealing option for homeowners looking for faster timelines and more predictable pricing.
Pros include a lower base unit cost, quicker installation, and standardized designs that reduce decision-making.
Cons include limited customization, variable build quality between manufacturers, and additional site-preparation costs. While base prefab units may be priced between $50,000 and $100,000, total project costs in Halifax often reach $200,000 to $300,000 once foundations, servicing, permits, and hookups are included.

Building a Custom ADU

A custom-built ADU offers maximum flexibility and long-term value.
Pros include full control over layout and finishes, higher construction quality, and seamless integration with your existing home and property.
Cons include higher overall costs, longer build timelines, and a greater need for careful budget management. In Halifax, custom ADUs typically range from $250,000 to $500,000+, depending on size, complexity, and finish level.

Permits and Legal Considerations in Halifax

Building an ADU in Halifax requires compliance with local zoning bylaws and the Nova Scotia Building Code. Permits are mandatory and typically include a building permit along with related plumbing, electrical, and water or wastewater approvals. Combined permit and review costs are often in the range of $1,500 to $2,000, depending on the scope of the project.

Some neighbourhoods may also have additional requirements related to heritage properties, setbacks, lot coverage, or parking. These factors are reviewed during the permit process and should be confirmed early to avoid redesigns or delays.

Timeline for Building an ADU

From early planning to move-in, most ADU projects in Halifax take 6 to 12 months to complete.

Design and permits: 2 to 4 months
Site preparation and foundation work: 1 to 2 months
Construction: 3 to 6 months

Weather conditions, material availability, and permitting backlogs can extend timelines, especially during peak construction seasons.

Long-Term Value of an ADU in Halifax

A well-designed and properly built ADU can significantly increase property value, generate steady rental income, and provide flexible living space for family members. Demand for legal, code-compliant ADUs continues to grow in Halifax, making them a strong long-term investment when constructed with durable materials and thoughtful design.

Most Expensive Parts of an ADU Project

Labour and materials typically make up 30 to 60 percent of the total ADU cost. Skilled trades such as plumbing, electrical, and HVAC installation are essential for meeting safety and building-code requirements. High-end materials like cedar siding, stone countertops, and energy-efficient windows can also add significantly to the overall budget.

Tips to Control ADU Costs

Choose a right-sized design to avoid unnecessary square footage
Use durable, mid-range materials that balance cost and longevity
Limit structural complexity to reduce labour time
Obtain multiple contractor quotes to ensure competitive pricing
Prioritize must-have amenities over nice-to-have upgrades

Final Takeaway

In Halifax, building an ADU can cost anywhere from $150,000 for a basic unit to $500,000+ for a luxury build, with most homeowners spending between $250,000 and $350,000 for a comfortable, well-designed, and code-compliant unit. By understanding the key cost drivers - size, materials, site conditions, and amenities - you can create a realistic budget that delivers long-term value.

If you are ready to explore your options, Halifax General Contractors can guide you through the entire process, from design and permitting to final construction, ensuring your ADU is built on time, on budget, and to the highest standards. Contact us today for a free, no-obligation consultation and take the first step toward your ideal secondary suite.