Best garage additions & conversions companies in Mississauga

★★★★★4.9 (86 reviews)score 89/100

M & D Buildings runs conversions as one-stop projects, coordinating structural, electrical, plumbing and finishing work under owner Mike, who reviewers say stays involved from the first walkthrough to the final punch list. With 86 reviews averaging 4.9 stars and repeat clients, it's the highest-confidence pick on this list for anyone who wants a single crew to take a garage from shell to finished space.

• Owner Mike involved start to finish
• Handles permits and engineering coordination in-house
• WSIB registered and PEO certified
• Daily communication and clean job sites

Services: garage additions conversions, garage permits design, detached garage construction, custom finishes heated garages

★★★★★4.9 (320 reviews)score 89/100

With 320 reviews at a 4.9 average, Garage Floors 4 Less HQ has the largest review base on this list and a proprietary 4-layer polyaspartic system backed by a 15-year transferrable warranty. Named crew members like Chris, Will and Heiner are repeatedly called out for explaining the process clearly and finishing on schedule.

• 4-layer system with 15-year transferrable warranty
• Crews explain the coating process in detail
• Consistently punctual and thorough cleanup
• Large, recent review volume backing the rating

Services: garage doors openers, garage permits design, garage additions conversions, detached garage construction

★★★★★4.8 (35 reviews)score 82/100

Koulani Contractors, led by Yaser, is best known for finishing bathroom and kitchen work to a polished standard, and that same discipline carries into garage conversion projects: reviewers highlight fair, transparent quotes and job sites kept tidy throughout. At 4.8 stars from 35 reviews, the sample is smaller but consistently positive.

• Yaser personally oversees attention to detail
• Meets timelines reliably
• Keeps work sites clean and organized
• Transparent, fair pricing across the GTA

Services: detached garage construction, garage additions conversions, carriage house laneway garage

★★★★★4.8 (22 reviews)score 76/100

Garage Solutions 4 Less turns neglected concrete into polyaspartic-coated floors and matching wall systems, with 20 of 22 reviews at five stars. Named technicians Marc, Teddy and Fabyan are credited with daily progress updates, which reviewers say made the process easy to follow.

• Polyaspartic coating and wall system expertise
• Daily communication updates during the job
• Named team members known for reliability
• Strong five-star ratio despite a smaller review count

Services: garage doors openers, detached garage construction, garage additions conversions, custom finishes heated garages

★★★★★4.9 (41 reviews)score 75/100

Happy Valley Home Builders specializes in legal basement and garage conversions across Mississauga and the GTA, with crew leads Ali and Tony named repeatedly for stress-free permit handling. At 4.9 stars from 41 reviews with no significant complaints recorded, it's a strong option for anyone converting a garage into a legal secondary unit.

• Legal unit and permit expertise
• On-time completion track record
• Affordable pricing relative to scope
• No significant complaints in the review history

Services: detached garage construction, garage additions conversions, garage permits design

★★★★★5 (13 reviews)score 74/100

Marathon Consultancy handles home additions, conversions and detached garages under Adam, with every review giving five stars and none flagging complaints. Reviewers point to quick response times and code-compliant finishes as the standout traits, though the review count of 13 is still modest.

• Quick response to enquiries
• Manages city permits and approvals directly
• Finishes on schedule
• Fair, straightforward pricing

Services: detached garage construction, garage additions conversions, carriage house laneway garage

★★★★★4.6 (39 reviews)score 66/100

Maki Construction, run by Mario, is regarded for coordinating complex projects from estimate through completion with hands-on owner involvement and craftsmanship reviewers call precise. At 4.6 stars from 39 reviews it sits a notch below the top tier, mainly due to some post-project follow-up issues in older reviews.

• Strong craftsmanship and attention to detail
• On-time, on-budget delivery on complex jobs
• Hands-on owner guidance through design decisions
• Efficient coordination across multiple trades

Services: detached garage construction, garage additions conversions

★★★★☆4.2 (132 reviews)score 76/100

Garage One Inc. built its reputation on speed, with technicians Hamza, Ahmed and Muhammed frequently named for same-day fixes and honest pricing across 132 reviews. The 4.2 average reflects a real split in outcomes though, so it's a stronger fit for straightforward repair or install jobs than for larger conversion projects.

• Same-day or next-day availability
• Named technicians with strong repeat mentions
• Transparent pricing with senior discounts
• Large review base for statistical confidence

Services: garage doors openers, detached garage construction, carriage house laneway garage, custom finishes heated garages

★★★☆☆3.3 (3 reviews)score 59/100

This Home Depot Home Services listing offers licensed, WSIB-certified contractor referrals, but the review record is extremely thin at just 3 reviews and a 3.3 average, with the one detailed account describing long waits and unhelpful staff. Treat this as a low-confidence entry until more recent feedback accumulates.

• Licensed and insured contractor network
• WSIB certified

Services: detached garage construction, garage additions conversions

★★★★★5 (1 reviews)score 53/100

This second Home Depot Home Services listing states it's a licensed, WSIB-certified contractor with $1M liability insurance covering renovation and installation work, but there is only a single five-star review to go on. It's included here for completeness rather than a demonstrated conversions track record.

• Licensed and insured
• WSIB certified

Services: detached garage construction, garage additions conversions