The integrity of your basement is vital to the rest of the home. So when things go wrong, such as mould and leaks, your first concern may be the basement leak repair costs, which can be high. Waterproofing your basement is your best defence against costly repairs caused by water damage. In this post, we will discuss waterproofing basement costs in Ontario (2025) and the factors that influence this cost.
Note: These average prices are based on research in 2025. Contact Harmony Basements for a free estimate.
Average Basement Waterproofing Cost per Square Foot in Ontario
Waterproofing prices are usually based on external waterproofing since this is the most thorough waterproofing method used. One way to determine the cost in Ontario is to know the price per square foot. The average cost of exterior waterproofing in Ontario is $6 – $8 per square foot.
Sometimes, you may get the cost listed as price per linear foot, so keep this in mind in your research. Further down, we will show you how to estimate the total cost based on the cost per linear foot and the size ( in square feet) of your basement.
Average Basement Waterproofing Cost in Toronto
How Much Does It Cost to Waterproof Basement in Ontario?
There are several factors that determine the final cost for waterproofing. A major one is the size of the basement, which you can use as a general estimate for the range to expect for the final cost if you’re given the price per linear foot.
Using the example of external waterproofing, which ranges between $90 and $320 per linear foot and a basement that is 900 square feet, we can calculate the price as follows:
We need to start by finding the perimeter.
Perimeter = 2 × (Length + Width)
We’ll assume that the basement is square for simplicity’s sake. In that case, the length and width would be the square root of the total size.
Length and width = √900 sq ft ≈ 30 ft
Now we can find the perimeter.
Perimeter = 2 × (30 + 30) = 120 linear ft
So to find the cost you can expect, we’ll use that range of $90 – $320.
120 × 90 = 10,800
120 × 320 = 38,400
So you would expect to pay between $10,800 and $38,400 to waterproof a 1000 sq ft basement.
Please note that other factors besides size will also be considered when estimating the cost to waterproof your basement, such as the waterproofing method, existing damage, foundation depth, additions needed (sump pump, weeping tiles, etc.), location, and geological conditions.
Get in touch to find out more about the services and costs we offer here at Harmony Basements, along with the processes and typical timelines involved.
Choose Harmony Basements for Your Next Waterproofing
Choose Harmony Basements as your trusted partner for basement waterproofing—because you deserve a company that’s honest, transparent, and committed to protecting your home. With years of proven expertise, we have the knowledge and skills to keep your basement dry, structurally sound, and ready for whatever project you have in mind.
Contact us today for a no obligation consultation with our team.
FAQs
For interior waterproofing, you might pay between $5,000 and $10,000, whereas with exterior waterproofing, you’re likely looking at least $10,000.
Although there are some DIY solutions that you can attempt when tackling minor issues, it’s important to know when to call in a professional who will get to the root of any issues and provide long-term solutions. Such issues include extensive or persistent water leaks or flooding, water stains, widespread mould growth, signs of sinking floors, walls that bow or slant, and cracks that are either horizontal or wider than ⅛ inch.
Even small leaks can eventually become a big problem, so it’s vital that you address any issues you come across as soon as possible. When it comes to professional intervention, external waterproofing is the way to go to address various elements that contribute to water damage in your basement. You can also modify your property to further enhance waterproofing. This includes adding a sump pump, backup sump pump, water wells, and weeping tiles. You can also regrade your yard, clean your gutters, and extend your downspouts to direct water away from the foundation.
The cost of professional waterproofing, which is strongly recommended, depends on whether exterior or interior waterproofing is done. The price for waterproofing a basement in Ontario starts at $90 per linear foot for exterior waterproofing and $50 per linear foot for internal waterproofing. Just make sure that your contractor is qualified and experienced and isn’t cutting on necessary products and processes. You want to be sure that the waterproofing deals with any root issues, otherwise you’ll soon have to redo the work.
It can take as little as a day or over five weeks. The length of time it takes to waterproof a basement depends on the waterproofing method, severity of the damage, and any prep work needed.
– Wall crack repairs and window well installations typically take a day or two.
– Exterior and interior waterproofing usually take two weeks.
– Basement walkout construction takes about four weeks.
– Both bench footing and basement underpinning can take five weeks.
– The time it takes to repair a foundation depends on the extent of the damage.
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