CORNERSTONE
Construction
We Listen, We Build, We Deliver
Professional residential and commercial renovations led by Mike Brock. Serving Oshawa, Whitby, Bowmanville, Ajax, Pickering, and Durham Region since 2017.
EVERY PROJECT. EVERY TIME.
The Cornerstone Certainty Stack
Eight guarantees that protect you from start to finish. No exceptions.
Your price is locked before we start. No surprise bills. Ever.
If we miss your completion date we pay you $300 for every day we run late.
Your home stays clean and dust-free throughout the entire build.
We clean up every single day before we leave. Your home stays livable throughout the entire project.
Track your project, approvals, and documents anytime through your JobTread portal. Full transparency from day one.
Every job is backed by a full 5-year workmanship warranty. We stand behind our work long after we're gone.
You get a complete Owner's Manual at handover with maintenance tips, trade contacts, and warranty details.
Ontario licensed and insured corporation. WSIB compliant. Ask for proof anytime.
Residential
Kitchens, bathrooms, basements, and whole-home renovations.
Commercial
Tenant fit-ups, office builds, and retail spaces. On time, on budget.
General Contracting
Full project management from permits to trades. One point of contact. No surprises.
Restoration
Insurance claims, flood and fire damage. We work with your adjuster.
GET STARTED
Find Your Project Fit
Ready to build? Book your free project diagnostic and we will assess your space, scope the work, and give you a fixed price before we start. No guessing. No ballpark numbers.
We Listen, We Build, We Deliver
Our systematic five-step methodology ensures every renovation project in the Durham Region meets Mike Brock's high standards of excellence.
We listen to your vision and assess your space to understand exactly what you need for your renovation.
Mike Brock and our team develop a detailed project roadmap, timeline, and transparent budget for your approval.
We help you choose the right materials for your budget and style. Everything is ordered and staged before we start.
Our skilled tradesmen execute the construction with precision, keeping you updated every step of the way.
We perform a rigorous quality walkthrough to ensure every detail is perfect before you enjoy your new space.
Renovation Investment Calculator
Select your project type and customize the details to see a rough estimate of your investment.
This is a rough estimate. Final pricing depends on your specific project. Contact us for an accurate quote.
Google Reviews & Testimonials
Real Stories from Durham Region
See how Mike Brock and the Cornerstone team are building excellence across Oshawa, Whitby, Bowmanville, and the GTA.
"From the 3 options I sourced, Mike was the most professional and punctual. We had a 5pm appointment and true to his word, my bell chimed exactly at 5pm. Throughout the entire process, Mike arrived on time every day, provided daily walkthroughs and next steps, and cleaned up every time. He will now be the only contractor to touch ANY part of my house. Professional: 10/10. Punctual: 10/10. Polite: 10/10. Knowledgeable: 10/10."
Verified Google Review
"We had a great experience working with this general contractor from start to finish. Communication was clear, timelines were respected, and the quality of work exceeded our expectations. Every detail was handled professionally, and any questions we had were addressed quickly. It's rare to find someone this reliable and skilled — highly recommend."
Verified Google Review
"Mike completed a large renovation for us in Durham Region. The project was well done, the attention to detail really makes it appear well done. Mike spends all of his time working on your project which makes it extremely easy to meet and review the project as it evolves. Overall a good experience."
Verified Google Review
"I am so impressed with the quality of work and professionalism of this company. Right from the beginning Mike was very responsive — coming to my home to really understand what needed to be done to give me the results I wanted within my budget. I highly recommend this company for any project."
Verified Google Review
"Dreams do come true. Mike and his team successfully transformed the kitchen into a stunning space. Their expertise and professionalism are reflected in the quality of their work."
Verified Google Review
Building Trust Since 2017
Cornerstone Construction delivers high-end results across Durham Region and the GTA. We listen, we build, and we deliver excellence on every project.
Recent Successes
View Full Portfolio| Rank | Project Type | Rating | Status |
|---|---|---|---|
| 1 | Whitby Full Main Floor Renovation (Kitchen, Bathroom, Hallway) | 5.0 | Completed |
| 2 | Bowmanville Full Main Floor Renovation (Kitchen, Bathroom, Hallway, Living Room, Dining Room) | 5.0 | Completed |
| 3 | Bowmanville Full House Renovation (Kitchen, 2 Bathrooms, Hallway, Living Room, Dining Room, Basement, Staircase) | 5.0 | Completed |
| 4 | Pickering Kitchen Renovation | 5.0 | Completed |
| 5 | Oshawa Kitchen Renovation | 5.0 | Completed |
WHERE WE WORK
Where We Build
Cornerstone Construction has been Durham Region's trusted renovation partner since 2017. We bring professional craftsmanship to every neighbourhood we serve.
Service Areas
Oshawa, Whitby, Bowmanville, Ajax, Pickering, Newcastle, Clarington, Scarborough, Stouffville, and Peterborough
Direct Line
647-521-7383
Business Hours
Monday – Friday: 8:00 AM – 6:00 PM
COMMON QUESTIONS
What Homeowners Ask Us
We listen, we build, and we deliver. Here is what you need to know before we start.
Have a specific project in mind?
Mike Brock and the team are ready to help with your next renovation. Book your free project diagnostic or call us directly.
"I started Cornerstone because homeowners deserve a contractor they can actually trust."
Mike Brock
Owner & General Contractor
GET STARTED
Ready to Build Your Vision?
Book your free Project Diagnostic. We assess your space, scope the work, and give you a fixed price before we start. No guessing. No ballpark numbers.
Licensed & Insured Ontario Corporation · Serving Durham Region Since 2017 · 5-Year Warranty on Every Job