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Find Expert Home Addition Contractors in Ottawa

Find experienced home addition professionals for room additions, second-storey builds, bump-outs, in-law suites, sunrooms, garage conversions and kitchen extensions across Ottawa and surrounding areas.

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Tell us your project, we'll connect you with home addition professionals

WSIB Advisory We recommend confirming Workplace Safety & Insurance Board coverage before work begins
Structural Expertise Foundation engineering, load-bearing analysis, roof tie-ins and full mechanical integration for seamless home additions
All Across Ottawa Ottawa Central, Kanata, Barrhaven, Orleans, Nepean, Glebe & beyond
Ottawa Addition Expertise Connecting you with addition contractors who understand Ottawa's deep frost line, heritage districts and extreme climate

Home Addition Services Across Ottawa

Find experienced addition contractors for residential and commercial projects throughout Ottawa

From $45,000

Room Additions

Expand your Ottawa home with a professionally built room addition including foundation, framing, roof tie-in and full mechanical integration.

  • New foundation with frost-line footings (1.2-1.5m deep)
  • Structural framing and roof tie-in to existing home
  • HVAC ductwork extension and electrical panel assessment
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$45,000 - $120,000
From $150,000

Second-Storey Additions

Add a full or partial second storey to your Ottawa home with structural engineering, foundation assessment and complete construction management.

  • Structural engineering assessment and load analysis
  • Foundation reinforcement or underpinning if required
  • Temporary roof removal and weather protection
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$150,000 - $350,000
From $25,000

Bump-Out Extensions

Extend your Ottawa room by 2-15 feet with a bump-out addition including foundation, structural integration and exterior matching.

  • Foundation extension below 1.2-1.5m frost line
  • Structural wall opening and header installation
  • Roof overhang extension and exterior cladding match
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$25,000 - $65,000
From $80,000

In-Law Suite Additions

Build a self-contained in-law suite addition in Ottawa with separate entrance, kitchen, bathroom and full fire separation per Ontario Building Code.

  • Self-contained unit with kitchen, bathroom and bedroom
  • Separate entrance and independent utility connections
  • Ontario Building Code fire separation compliance
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$80,000 - $180,000
From $30,000

Sunroom Additions

Add a three-season or four-season sunroom to your Ottawa home with proper insulation, glass selection and heating for extreme winters.

  • Three-season or four-season design options
  • Triple-pane low-E glass for four-season rooms
  • Foundation with frost-line footings for permanent structures
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$30,000 - $75,000
From $35,000

Garage Conversions

Convert your Ottawa garage to finished living space with insulation, HVAC, electrical upgrades and Ontario Building Code compliance.

  • Wall and ceiling insulation to OBC standards
  • Floor leveling and subfloor insulation system
  • HVAC ductwork extension or dedicated mini-split
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$35,000 - $85,000
From $50,000

Kitchen Extensions

Expand your Ottawa kitchen with a rear or side extension including structural modifications, utility relocation and full finishing.

  • Load-bearing wall removal with engineered beam support
  • Foundation extension with frost-line footings
  • Plumbing and gas line relocation
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$50,000 - $130,000

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Get instant answers to your home addition, room extension, structural and permit questions from our expert knowledge base

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Why Use Ottawa Additions

Free Matching Service

Our service costs homeowners nothing. Describe your home addition project and we match you with professionals who specialize in that exact type of work -- from residential home extension to commercial home addition. No fees, no obligation.

Ottawa-Wide Coverage

From room additions in Kanata to second-storey builds in the Glebe, bump-outs in Barrhaven, and in-law suites across Orleans. We match you with addition contractors who know your area and project type.

Ottawa Construction Network

Backed by the Ottawa Construction Network -- Ottawa's contractor directory with hundreds of listings across every construction trade.

Frequently Asked Questions

How much does a home addition cost in Ottawa?

Home addition costs in Ottawa range from $250 to $400 per square foot for room additions, $350 to $500 for second-storey additions, and $150 to $300 for bump-outs. A typical room addition runs $45,000 to $120,000, while a second-storey addition costs $150,000 to $350,000. Ottawa pricing is approximately 10 to 15 percent below Toronto rates.

What permits do I need for a home addition in Ottawa?

All home additions require a building permit from the City of Ottawa's Building Code Services. You will also need ESA permits for electrical work and TSSA permits for gas heating. Heritage conservation districts require additional heritage approval. Call 3-1-1 for permit questions or apply through the City's online portal.

How long does a home addition take in Ottawa?

A room addition typically takes 10 to 16 weeks, while a second-storey addition takes 16 to 28 weeks. Ottawa's primary building season runs May through October for exterior work, though interior finishing continues year-round. Plan to start permits and design in winter so you can break ground in spring.

Should my addition contractor have WSIB coverage?

Yes. In Ontario, WSIB coverage protects you from liability if a worker is injured on your property. Your contractor should carry a valid WSIB clearance certificate and minimum $2 million in liability insurance. For second-storey additions, verify the structural engineer carries professional liability insurance as well.

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