Trusted Since 2004
What Sets Cornerstone Apart
Trusted by Toronto homeowners since 2004. Verified expertise, transparent pricing, and industry-leading warranty protection.
Emergency Service Available
Active leak or structural concern? We move Toronto and GTA jobs to the front of the line.
Wet basement emergency? See waterproofing. Structural crack or bowing wall? Visit foundation repair.
Have Questions? Our Foundation Experts Are Ready to Help.
Client Reviews
Based on 44 verified HomeStars reviews
Toronto's top-rated basement waterproofing & foundation repair contractor
"Cornerstone fixed a leak in our basement. The crew was skilled, tidy, on time, and finished on schedule."
"Cornerstone was recommended to us by friends. This is an owner-led business that takes great pride in its work. From start to finish Saverio LoMonaco and his crew were prompt, friendly, efficient and performed excellent work. There is still one part of the work to be completed (the laying of concrete to repair the pathway) because the work already completed requires time to settle. Other contractors might have proceeded only to produce problems up the road. I highly recommend Cornerstone."
"Saverio and his crew dug out and underpinned my basement. The service, in terms of job completion, communication throughout, finishing and even offering advice and suggesting other contractors to help complete my project. This was my first big reno and I had never been my own general contractor before. With Saverio's assistance, I was able to lower my basement floor by 24 inches, reroute the sewage, waterproof, and build an escape access from the basement. He and his crew were fast, and he communicated with me throughout the project, which helped with peace of mind. He even suggested great, professional contractors that allowed me to finish my project. All-around I highly recommend Cornerstone."
"Exceptional service. Exceptional work. We had an excellent experience with Saverio and his crew. From the get-go Saverio was available to answer all my questions thoughtfully and honestly about underpinning our basement and never tried to push us to make a quick decision. The crew that works for him were at our house at the same time every day, entirely respectful of our neighbours and finished the project on schedule. Since the completion of our basement project Saverio continues to be invaluable to use as a problem solver when we had an issue with the city pipes outside of our house. I highly recommend Cornerstone Waterproofing for anyone that is looking for high-quality, reliable service!"
Quick FAQ
Frequently Asked Questions About Toronto Services
Get answers to common questions about waterproofing, foundation repair, and underpinning services in Toronto.
How much does basement waterproofing cost?
Basement waterproofing costs vary based on foundation length, soil conditions, and whether you choose interior or exterior methods. Interior waterproofing is typically faster and more affordable, while exterior solutions address water at the source. We provide free on-site inspections with detailed pricing breakdowns tailored to your specific needs. Contact us for an accurate quote.
What's included in your 20 year warranty?
Our 20 year warranty covers all materials and workmanship in treated areas, including waterproofing systems, foundation repairs, sump pump installations, and drainage work. We stand behind every project and will return at no cost to make it right if an issue arises. Call or contact us for full warranty details and any specific project considerations.
Do you work year-round in Toronto?
Yes, we operate year-round and can handle emergency repairs when needed. Some exterior work is weather-dependent, so winter conditions may affect excavation schedules. For urgent waterproofing or structural concerns, we prioritize fast response based on site conditions. Contact us to discuss your project and seasonal timing.
What areas do you serve?
We serve Toronto and the Greater Toronto Area (GTA) including East York, North York, Scarborough, Mississauga, Brampton, and surrounding neighborhoods. We've completed over 2,500 projects across the region and understand Toronto's unique housing challenges—clay soil, freeze-thaw cycles, and older home foundations.
What causes foundation cracks and how are they fixed?
Foundation cracks result from settling, freeze-thaw cycles, hydrostatic pressure, and soil movement—all common in Toronto. We don't do band-aid crack injection fixes. Instead, we excavate and apply industrial-grade waterproofing membranes with proper drainage systems for permanent protection. Horizontal cracks or bowing walls require structural reinforcement. We assess each situation honestly and recommend only necessary repairs. Contact us for a detailed assessment and pricing specific to your foundation's condition.
Do you provide services for commercial properties?
Yes. We serve both residential and commercial properties across the GTA. Our commercial services include waterproofing for parkades and retail spaces, foundation repair for multi-unit buildings, concrete work for loading docks and warehouse floors, and new foundation installations for commercial projects. We work directly with property managers, building owners, and commercial contractors with detailed documentation and scheduling that minimizes operational disruption.
Have more questions? We're here to help.
Toronto Basement Assessment
Site Visits Arranged When Convenient
Share details below and we'll leave you with a clear moisture-control or Toronto foundation repair plan. Progress photos available upon request.
Call or Text
(416) 879-4593
cornerstone@live.ca
Location
Based in East York • Serving the GTA
