Durham Region & GTA
Built for Businesses That Can't Afford to Wait
Cornerstone Construction delivers commercial renovations for businesses across Durham Region and the GTA — run with the same deadline discipline Mike built opening retail stores before he ever touched a home. Licensed, insured, and backed by our Certainty Stack.
What We Build
Commercial Services
From single office fit-ups to full commercial renovations — one team, one contract, everything handled.
Office & Medical Fit-Ups
Full office and medical clinic build-outs from shell to finished space. Demising walls, flooring, ceilings, electrical, data rough-in, exam room plumbing, and paint. We build spaces people actually want to work in.
Retail Renovations
Storefront upgrades, interior reconfigurations, display builds, and full retail fit-outs. We understand retail timelines and work to minimise your downtime.
Restaurant & Kiosk Construction
Commercial kitchen rough-ins, dining room builds, kiosk construction, and food service fit-outs. Built to health code and ready for inspection.
Interior Fit-Ups
Tenant improvement work for landlords and property managers. We coordinate with building management and deliver clean professional finishes on schedule.
Landlord Work
Suite turnovers, common area upgrades, damage repairs, and building improvement projects. We keep your tenants happy and your building in top condition.
General Commercial Contracting
Have a commercial project that needs a single point of contact? We manage trades, timelines, and quality from start to finish.
Our Process
How We Work
Every commercial project follows the same four-step process. Clear. Accountable. On schedule.
Site Consultation
We visit your space, understand your scope, and learn how your business operates. We ask the right questions before we touch a single wall.
Detailed Proposal
You receive a full written proposal through your real-time client portal with a complete cost breakdown, phase plan, and locked price before any work begins.
The Build
Your named supervisor manages every trade on site. We work around your schedule, clean up daily, and keep you updated through your real-time client portal.
Handover
Final walkthrough with Mike. We confirm every item is complete to standard. You receive your 5-year warranty and Owner's Manual. The space is yours.
Why Cornerstone
Why Businesses Choose Cornerstone
Before residential renovations, Mike ran retail and hospitality commercial build-outs — store openings and restaurant launches with a hard deadline and no room for excuses. That discipline is still how we run every commercial job.
Minimal Disruption
We work around your schedule. Early mornings, evenings, weekends — the same buffer-built scheduling that opened stores on a live launch date, now built into your project.
One Point of Contact
Mike Brock or a named supervisor manages your project from day one. No handoffs. No confusion. You always know who to call.
Built to Code
Every commercial project meets Ontario Building Code requirements. We pull the permits, coordinate inspections, and deliver a space ready for occupancy.
Common Questions
Frequently Asked Questions
Everything you need to know about our commercial construction process, permits, and service options.
What types of commercial properties do you service?
We specialise in office fit-ups, retail spaces, restaurants, and medical clinics across Durham Region and the GTA, ensuring every project meets specific industry standards.
How do you minimise disruption to business operations?
We offer flexible scheduling, including after-hours and weekend work, to ensure your business stays operational and your customers are undisturbed during the renovation process.
Are you licensed and insured for commercial work?
Yes. Cornerstone Construction is fully insured, WSIB compliant, and highly experienced in meeting strict commercial building codes and safety regulations in Ontario.
Do you handle the permit process for commercial projects?
Yes. We manage the entire process from permit applications to final inspections, ensuring your project is fully compliant with local bylaws. You do not deal with the municipality. We do.
What is your typical turnaround for an office fit-up?
Timelines vary by scale but most fit-ups range from 4 to 12 weeks. We provide a detailed project schedule during our initial consultation so you can plan your move-in accordingly.
Do you offer emergency restoration for commercial clients?
Yes. We handle insurance restoration for water, fire, and wind damage — documenting the damage and building a complete, code-compliant rebuild scope so you're never negotiating your claim alone. See our Insurance Restoration page for how it works.
Commercial Fit-Ups
Done Right
Tell us about your project using the form. We review every submission personally and follow up within one business day with a direct call from Mike.
What to include:
- Type of commercial space
- Scope of work or renovation goals
- Project address and timeline
- Any drawings or plans you have ready
If you'd rather talk first — call us directly.
