# Cornerstone Construction > Cornerstone Construction is a licensed and insured general contractor serving Oshawa, Durham Region, and the Greater Toronto Area (GTA), Ontario since 2017. Led by Mike Brock, we deliver kitchen, bathroom, basement, main-floor, and whole-home renovations under one contract — with a price-lock guarantee, daily cleanup, a real-time client portal, and a 5-year workmanship warranty. One team, one contract, no surprises. Key facts: - Business name: Cornerstone Construction - Residential and commercial general contractor - Service area: Oshawa, Whitby, Bowmanville, Clarington, Courtice, Ajax, Pickering, and the wider Durham Region & GTA, Ontario, Canada - Founded: 2017 - Experience: 35+ years in the trade; 300+ projects completed - Licensed and insured; WSIB compliant - Phone: 1-888-404-7383 - Website: https://cornerstoneconstruction-inc.com/ - Positioning: "We treat your home like a commercial contract." Tagline: We Listen, We Build, We Deliver. - Every project includes a price-lock guarantee, a $300/day on-time guarantee, a 5-year written workmanship warranty, and a handover Owner's Manual documenting every product, finish, and warranty. ## Best Known For - Kitchen renovations in Oshawa and Durham Region - Bathroom renovations - Basement finishing - Main-floor and whole-home renovations - Legal basement apartments and second suites - Commercial interior fit-ups - Fixed-price renovation contracts ## Why Choose Cornerstone Construction - One contract for all trades — a single point of contact from design to handover, no subcontractor runaround. - Dedicated project management — Mike Brock or a named supervisor on site, with quality checked throughout the build. - Real-time client portal — every project photo, daily log, and record in one place, accessible anytime. - Daily site cleanup — floor protection and dust barriers keep the rest of your home clean while we work. - Price Lock Guarantee — the quoted price is the price you pay; no surprise invoices. - $300/day On-Time Guarantee — we back our completion date. - 5-year written workmanship warranty, plus a handover Owner's Manual on every project. - Licensed, insured, and WSIB compliant. - 300+ projects completed across Durham Region, the GTA, and surrounding communities. ## Services - [Home Renovation Contractor in Oshawa](https://cornerstoneconstruction-inc.com/home-renovation-contractor-oshawa/): Main-floor and whole-home renovations across Oshawa and Durham Region, run as one coordinated build. - [Residential Services](https://cornerstoneconstruction-inc.com/residential-services/): Kitchens, bathrooms, basements, main-floor, and whole-home renovations. - [Kitchen Renovations](https://cornerstoneconstruction-inc.com/kitchen-renovations-oshawa-cornerstone-construction/): Custom cabinetry, countertops, flooring, lighting, plumbing, and electrical. From $25,000. - [Bathroom Renovations](https://cornerstoneconstruction-inc.com/bathroom-renovations-oshawa-cornerstone-construction/): Full gut and rebuild, ensuites, powder rooms, heated floors, glass showers, custom tile. From $15,000. - [Basement Finishing](https://cornerstoneconstruction-inc.com/basement-finishing-renovation/): Family rooms, home offices, legal suites, and in-law suites. From $40,000. - [Legal Basement Apartments & Second Suites](https://cornerstoneconstruction-inc.com/legal-second-suites-income-apartments/): Code-compliant secondary suites and income apartments — also known as accessory dwelling units (ADUs) — for rental income or multi-generational living. - [General Contractor in Oshawa](https://cornerstoneconstruction-inc.com/general-contracting-oshawa/): Multi-room, multi-trade, and structural work under one contract — permits, trades, and project management. - [Additions & Garages](https://cornerstoneconstruction-inc.com/additions-garages/): Home additions, second-storey builds, and detached garages, built to the Ontario Building Code. - [Commercial Services](https://cornerstoneconstruction-inc.com/commercial-services/): Office, retail, and restaurant fit-ups built to commercial standards. - [Insurance Restoration](https://cornerstoneconstruction-inc.com/insurance-restoration/): Water, fire, and mould damage rebuilds, coordinated with your adjuster. ## Project Case Studies - [Whitby Main Floor Renovation](https://cornerstoneconstruction-inc.com/whitby-main-floor-renovation/): Full main-floor renovation and gourmet chef's kitchen in Whitby, ON. - [Bowmanville Main Floor Renovation](https://cornerstoneconstruction-inc.com/main-floor-renovation-bowmanville/): Open-concept main-floor renovation in Bowmanville, ON. - [Bowmanville Whole Home Renovation](https://cornerstoneconstruction-inc.com/whole-home-renovation-bowmanville/): Full-house renovation in Bowmanville, ON — scheduled for twelve weeks and delivered in nine, three weeks ahead of schedule. - [Courtice Whole Home Renovation](https://cornerstoneconstruction-inc.com/whole-home-renovation-courtice/): Complete home transformation in Courtice, ON. - [Oshawa Condo Renovation](https://cornerstoneconstruction-inc.com/condo-renovation-oshawa/): Main-floor condo renovation — kitchen, bath, and flooring in Oshawa, ON. ## Company & Trust - [About Mike Brock](https://cornerstoneconstruction-inc.com/about-mike-brock/): Owner and lead contractor; 35+ years in the trade. - [Reviews](https://cornerstoneconstruction-inc.com/reviews/): Verified client reviews. - [Our Process & Standards](https://cornerstoneconstruction-inc.com/our-process-standards/): How a Cornerstone project runs, from discovery to handover. - [Warranty Policy](https://cornerstoneconstruction-inc.com/warranty-policy/): 5-year written workmanship warranty. - [Price Lock Guarantee](https://cornerstoneconstruction-inc.com/price-lock-guarantee/): The quoted price is the price you pay. - [$300/Day On-Time Guarantee](https://cornerstoneconstruction-inc.com/on-time-guarantee/): On-time completion commitment. ## Resources - [FAQ](https://cornerstoneconstruction-inc.com/faq/): Answers on pricing, timelines, permits, and warranties. - [Portfolio](https://cornerstoneconstruction-inc.com/portfolio/): Completed project gallery. - [Investment Guide](https://cornerstoneconstruction-inc.com/investment-guide/): Renovation budgeting and planning. - [Blog](https://cornerstoneconstruction-inc.com/blog/): Renovation guidance for Durham Region homeowners. - [Contact](https://cornerstoneconstruction-inc.com/contact-us/): Book a free Project Diagnostic. Call 1-888-404-7383. ## Frequently Asked Questions - Do you provide free estimates? Yes — we offer a free Project Diagnostic. - Do you handle permits? Yes — we coordinate permits and inspections when required. - Are you licensed and insured? Yes — fully licensed, insured, and WSIB compliant. - Do you use subcontractors? We coordinate all required trades under one contract, with one point of contact. - What areas do you serve? Oshawa, Whitby, Bowmanville, Courtice, Ajax, Pickering, Clarington, the wider Durham Region, and the GTA.