Home additions

The 10 Best Home Addition Contractors in London, ON

Updated 131 firms checked10 ranked

This list ranks 10 home addition contractors in London, ON. It starts from Google Maps searches for home additions and related building work in London: 131 firms were checked, and building and renovation firms with their own website and an open Google listing went forward. Firms are weighed on their Google rating, the number of reviews behind it, how closely their services match home addition work, and their portfolio. The strongest firm overall sits at place 1, places 2 to 4 carry a badge for what each suits best, and places 5 to 10 run in order. Ratings and review counts are Google's, checked October 14, 2026. How we rank

Evergreen Design + Build

Best overall

London, Ontario design-build firm doing full-home renovations, home additions, kitchens, bathrooms and basements, as well as custom homes.

Updated

Why it ranks here

  • Works with each client from the first concept through to the final build.
  • Designs and builds home additions, from family rooms to second-storey master suites and garage conversions.
  • Builds custom homes on vacant lots and teardown sites, from site evaluation through to final finishes.
  • Its kitchen work runs from custom cabinetry and countertops to lighting and finishes.
Home additions · Full-home renovations · Kitchen renovations · Basement renovations · Custom homes London
Visit website Call 519-495-0157
5.0 from 35 Google reviews

Vantage Built Construction

Best for garage additions

London, Ontario renovation contractor doing home and garage additions, basement and kitchen renovations, and general contracting.

Updated

Why it ranks here

  • The company is a member of the London Home Builders Association.
  • Each job starts with an on-site visit to assess scope, site conditions, timelines and logistics.
  • Its design team lays out the floor plan, and the firm arranges the architectural drawings and engineering.
  • Manages projects from concept to finish in three stages: on-site consultation, design and build.
General contracting · Home additions · Garage additions · Basement renovations · Kitchen renovations London
Visit website Call 519-860-8426
5.0 from 32 Google reviews

Ivy Build

Best for engineered second units

London, Ontario design-build firm combining design, structural engineering and construction, including second units such as basement apartments and garden suites.

Updated

Why it ranks here

  • Brings design, structural engineering and construction together under one contract and one team.
  • Publishes a London Zoning and ARU By-Law Hub on its website for property owners.
  • The construction side draws on 25+ years of on-site experience.
  • Builds second units such as basement apartments and garden suites on existing properties.
Design-build · Structural engineering · Basement apartments · Garden suites London
Visit website Call 519-694-8841
5.0 from 13 Google reviews

Kuzyn Construction

Best for pre-designed ADU models

Family-owned London, Ontario builder of custom homes, garden suites and other ADUs, multi-unit housing and renovations with in-house millwork.

Updated

Why it ranks here

  • Began as a one-man operation and has grown into a family-owned construction and development company.
  • The company reports 80+ completed projects to date.
  • Lists a 2024 nomination in the London Urban Design awards.
  • Sells pre-designed detached ADU models, named The Paul, The Maria and The Henry.
  • Makes its own staircases, custom cabinets and architectural millwork in-house for interior renovations.
  • Also builds duplexes, triplexes and quadplexes, commercial fit-outs and steel roofs.
ADUs and garden suites · Custom homes · Interior renovations · Multi-unit builds · Steel roofs London
Visit website Call 519-694-4776
5.0 from 12 Google reviews

Ranks 07 to 10

Centennial Home Renovations

Construction company

5.0 226-289-3581CallWebsite

Lux Homes Design & Build

Home builder

4.7 519-857-8888CallWebsite

Rooney's Contractors

Roofing, masonry and waterproofing contractor based in London, Ontario, also doing foundation and chimney repairs, stucco and driveways.

5.0 226-503-8629CallWebsite

1st Choice Home Solutions

London, Ontario exterior renovation company installing metal and asphalt roofs, siding, soffit and fascia, windows, doors and eavestroughs.

4.6 519-268-6331CallWebsite

Compare the firms

FirmBest forServicesGoogle ratingArea
01Evergreen Design + BuildAdditions designed and built by one firmHome additions · Full-home renovations · Kitchen renovations · Basement renovations · Custom homes5.0London
02Vantage Built ConstructionGarage additionsGeneral contracting · Home additions · Garage additions · Basement renovations · Kitchen renovations5.0London
03Ivy BuildEngineered second unitsDesign-build · Structural engineering · Basement apartments · Garden suites5.0London
04Kuzyn ConstructionPre-designed ADU modelsADUs and garden suites · Custom homes · Interior renovations · Multi-unit builds · Steel roofs5.0London
09Rooney's ContractorsRoof, masonry and foundation repairsRoofing · Masonry repairs · Waterproofing · Foundation repairs · Chimney repairs5.0London
101st Choice Home SolutionsRoof, siding and window replacementMetal roofing · Siding, soffit and fascia · Windows and doors · Eavestroughs · Asphalt shingle roofing4.6London

What to check before hiring a home addition contractor in London

Five things to confirm with any firm, on this list or not, before you sign. The rules below are Ontario's and London's.

  1. Registration with the WSIB

    Ask the firm for a clearance certificate from the WSIB, which confirms it is registered for workers' compensation and its account is in good standing. The certificate confirms the firm is registered with the WSIB and up to date on its premiums, so check its dates cover your job.

  2. Liability insurance

    Ask for a certificate of insurance that names the firm and shows commercial general liability coverage in force for the dates of your job, and check that the subcontractors it brings in are covered too.

  3. The building permit from London

    Building permits for homes in London come from the City of London, and every addition needs one, and often a zoning review first. Agree in writing who applies for the permit and books the inspections.

  4. A written contract

    Get the scope of work, the payment schedule tied to stages of the work, start and finish dates, how changes are agreed and priced, and who handles permits and cleanup, all in one signed contract before any work starts.

  5. The warranty

    A renovation is not a new home, so the new home warranty rules usually do not apply: get the firm's own workmanship warranty in writing, with what it covers and for how long. Renovators in RenoMark, the Canadian Home Builders' Association program, offer a minimum two-year warranty on their work.

Types of home addition contractor in London

The 10 firms on this list fall into 4 groups, read from what each firm's own site says it does and how it is listed on Google.

Home builders4

Home builders build new houses as their main work, and some take on additions and major renovations too.

General contractors3

General contractors run building projects of many kinds and bring in the trades each job needs.

Design-build firms2

Design-build firms design the project and build it under one contract, so one firm answers for the drawings and the work.

Renovation companies1

Renovation companies renovate existing homes, one room at a time or all of it at once.

Home additions in London: common questions

Do I need a permit for a home addition?

Yes. An addition changes the footprint or height of the house, so it needs a building permit and often a zoning review for setbacks and lot coverage. Plans are usually drawn by a designer or architect before the permit application goes in.

Can I add a second storey to my house?

Often, but the existing foundation and walls have to carry the new load. An engineer checks the structure before design starts, and the contractor builds to those drawings.

What happens before an addition is built?

A survey of the lot, a check of the zoning rules for setbacks, height and lot coverage, drawings by a designer or architect, an engineer's review where the structure is affected, and the building permit. Ask the firm which of these steps it handles and which it expects from your designer.

Can I live in my house while an addition is built?

Often. Most of the work happens outside the existing walls until the new space is joined to the house. Expect noise and dust, and a few days without power or water when the addition is tied in.

How do I check that a contractor in London is registered with WSIB?

Ask the firm for a clearance certificate from the WSIB. The certificate confirms the firm is registered with the WSIB and up to date on its premiums, so check its dates cover your job.

Who issues building permits in London?

Building permits for homes in London come from the City of London. For home addition work, every addition needs one, and often a zoning review first. Many firms apply for the permit as part of the job, so agree who does it before you sign.

Before you get quotes

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