Basement Waterproofing in Markham
Markham runs from heritage homes on Main Street Unionville to new builds off Major Mackenzie, and they flood very differently.
Markham is mostly 1990s onward subdivision housing with deep finished basements, alongside the heritage core of Unionville and Markham Village.
Sump pump failure is the most common cause in the newer subdivisions, where basements sit below the water table and depend entirely on the pump. The heritage core has the opposite problem: old drains and stone foundations.
Cleaning up a flood twice is a choice. Once the property is dry, the useful question is why the water got in and what it would cost to keep it out.
Covered by insurance? We bill your insurer directly, so in most cases you pay only your deductible.
Where we work in Markham
We cover the whole of Markham, including Unionville, Milliken Mills, Thornhill, Cornell and every neighbourhood in between. Postal areas L3P, L3R, L3S, L3T, L6B, L6C and others.
Full neighbourhood list (16)
Signs your basement needs attention
- Water entering only when it rains heavily
- Damp patches or efflorescence on foundation walls
- Visible cracks in poured concrete or block
- A floor drain that backs up in storms
- A sump pit that fills faster than the pump clears it
- Window wells that fill with water
- Persistent humidity and musty smell
What we install
- Polyurethane crack injection for poured foundations
- Interior weeping tile and drainage systems
- Exterior excavation and membrane waterproofing
- Sump pump installation and replacement
- Battery backup sump systems for power outages
- Backwater valve installation
- Window well drainage and covers
- Downspout extensions and grading corrections
Who we do this for
- Homeowners who have already flooded once
- Buyers of homes with a water history
- Landlords protecting a basement unit
- Property managers
- Anyone applying for the City subsidy
When to call us in Markham
After the drying is finished, or before spring thaw if you already know you have a problem. It is the one part of this work you get to schedule rather than have forced on you.
What basement waterproofing in Markham costs you
We bill your insurance company directly. On most covered losses that is the only amount you pay us.
Water damage is the most common home insurance claim in Ontario, and the great majority of the work we do is paid by an insurer rather than by the property owner. We document every loss from the first hour with moisture readings, photographs and a written scope, which is the evidence an adjuster needs to approve the work without argument or delay.
We work with all major Canadian insurers and handle the claim from start to finish, including the adjuster's questions. If you are not insured, or the loss falls outside your policy, we will give you a clear written quote before any work begins and we will tell you honestly what can be dried and saved rather than replaced. Keeping material in place is what keeps the cost down, and it is the first thing we look at.
There is no charge for attending to assess an emergency, and no obligation once we have. What your policy covers →
Who turns up in Markham
Delta24 Restoration is a professional restoration contractor serving Toronto and the Greater Toronto Area. Our technicians are certified by the IICRC, the industry standards body for the restoration trade, in Water Damage Restoration (WRT) and Applied Structural Drying (ASD). We are WSIB cleared and carry full commercial general liability insurance. Certificate numbers and a current clearance certificate are provided on request, and property managers and adjusters routinely ask for both before we attend.
We work to the IICRC S500 standard for water damage restoration and the S520 standard for mould remediation. Every job is documented with daily moisture readings, photographs and a written scope, which is why adjusters approve our work without delay.
Asbestos work is carried out to Ontario Regulation 278/05, which sets out the procedures for Type 1, Type 2 and Type 3 operations. Mould work finishes with written post-remediation verification, which is the document a buyer, a lender or an insurer will ask to see.
- IICRC WRT certified technicians
- IICRC ASD certified drying
- WSIB cleared, certificate on request
- Commercial general liability insurance
- Asbestos work to O. Reg. 278/05
- Direct billing with all major Canadian insurers
- Years of insurance claim experience with every major insurer
- Written post-remediation verification on mould work
- Free assessment, no obligation
How the insurance side works
Water damage is the most common home insurance claim in Ontario, and how the claim is handled usually matters more to your bill than the work itself. We document the loss from the first hour: moisture readings, photographs, a written scope, and a daily drying log. That is the evidence an adjuster needs to approve the work without arguing about it.
We bill your insurer directly. In most cases the only money you hand over is your deductible, which on Ontario policies commonly sits between $500 and $2,500.
Which losses are covered depends entirely on where the water came from. A burst pipe or a failed appliance is normally covered under a standard policy. Water coming up through a floor drain is sewer backup, which is almost always a separate endorsement you have to have purchased. Water entering from outside during heavy rain is overland flood, which is another endorsement again. A single storm can produce all three at once, which is why adjusters care so much about the source.
Full guide: is a flooded basement covered by insurance? →
How the claim works, and what your insurer covers →
Common questions
Why do Markham basements depend on the sump pump?
Much of the newer subdivision housing has basements below the local water table, with a weeping tile system feeding a sump pit. If the pump fails or the power goes out during a storm, water has nowhere to go.
Do you serve Unionville and the heritage homes?
Yes. Older Unionville properties need a different approach, particularly around stone and rubble foundations, and we treat them accordingly.
What is a backwater valve?
A one-way valve fitted on your sanitary line that closes if the municipal sewer surcharges, stopping sewage entering the house through floor drains and toilets. It is the standard protection against sewer backup.
Does the City of Toronto pay for it?
The Basement Flooding Protection Subsidy Program offers up to $6,650 per property toward eligible flood protection work for single-family, duplex, triplex and fourplex homes. Terms change, so confirm the current amount and eligibility on toronto.ca.
Interior or exterior waterproofing?
Exterior addresses water before it reaches the wall and lasts longest, but it means excavation and it costs more. Interior systems manage water that has already entered and are less disruptive. Which is right depends on the foundation and the source.
Do I need a battery backup on my sump pump?
In the GTA, storms and power cuts arrive together. A sump pump without backup power is a pump that stops working at the moment you need it.