Why Water Leaks In Toronto Basement

Why Water Leaks In Toronto Basement

Moisture in the basement can be a real pain. At the very least, it can result in mold-related problems. At the worst, it can ruin the contents of your basement, including the carpets and any fabrics on your walls or ceiling and lead to long-term foundation damage.  In between these outcomes are issues like health considerations, and your basement becoming downright uninhabitable. Most homes in Toronto do not have basements meant for living space, though many people use them this way due to rising real estate prices and land scarcity.

The solution is knowing what to look for when it comes to water leaks, and what to do about it when you find it.

Plumbing Problems

Water heaters and washing machines bring water down into the basement. This is fine, until they – or the pipes themselves – spring leaks. This often happens when they start pumping after a dormant period during which something may have settled. Make a habit of checking the floor for water regularly, and, if you find it, to discover where it’s coming from.  If pipes are hidden behind drywall, look for signs of water damage and check the base of the wall to look for wet or crmbling drywall.

water leaking through basement walll

Water Leaking Through Basement Wall

Natural Water Intrusion

The rest of your basement water problems will likely come from intrusion of natural water from outside the basement space itself – unless it is dripping through the ceiling slab from the house above. Think logically about where it could be coming from.

  • Hairline Plaster Cracks may admit moisture that has penetrated through the bricks against the excavation, and generally show as a little water running down and marking the wall. This is usually the only source of natural water that you can stop effectively by scraping out the gaps, and backfilling with a proprietary waterproofing sealer.  If the leak is very small and not expanding, this method may work.  If it is a progressive water leak and causing ongoing foundation erosion, then the source of the water leak will need to be addressed or else you may face foundation issues later on the down the line along with a more expensive waterproofing solution.


  • The joint between the walls and floor is an obvious space to start looking, because builders construct them in two phases, and a tiny crack can develop between them as the building settles. The only workable solution is to chop up the edge of the floor, construct a french drain to lead the water to a sump pump, and cover neatly over again.  This type of interior waterproofing (actually water management) is called a weeping tile system.  Interior waterproofing solutions are good options when exterior waterproofing is not an option due to accessibility, foundation concerns and cost.


  • Water swelling through the floor slab manifests itself in the form of damp spots or worse puddles. Again, the only solution is to lay a line to lead it to a pump (weeping tile system). Usually for type of water leak, general waterproofing procedures won’t work, you’ll have to channel that water away from your basement. Water welling upwards under pressure will eventually find a way through anything, and you will be right back to square one again.  A good water management strategy is essential if you hope to use your basement for living space or at the very least, avoid mold issues.


  • Outside doors and ground-level hatches present a raft of different problems, all of which are curable if you do it properly. The only effective way is to raise the door lintel above the ground, or to set the hatchway on a masonry box high enough to keep the water out. Anything else, again, is bound to fail eventually as it will always be fighting water trying to find its way in, better to just get the entry points out of the way of the water.


  • Windows set in outside basement walls should be as waterproofed as those in the house itself – and provide equally trouble-free service. Window wells are actually one fo the most common sources of water leaks in a basement, usually due to age and lack of maintenance. If they are leaking, the correct solution is to rip them out and replace them with an energy efficient alternative. Mucking around with silicone seal is usually a waste of time if the window needs repair along with the drainage system built around it.
water leaking through basement floor

Water Leaking Through Basement Floor

Staying Out of Trouble

If we did no maintenance on our houses, then the roofs and walls would eventually start admitting water.  Foundations age, settle and start to compromise over time, and if you have water trying to get in, becomes a problem for the homeowner.  That they do not, is proof that prevention’s better than cure. Do not neglect your basement as half of homeowners do, and put up with potentially harmful water intrusion and health concerns.  Inspect it regularly.

Nusite Waterproofing has been serving Toronto and the surrounding GTA for over 30 years.  We are experts in basement waterproofing and foundation repairs.  We offer a free in-home inspection and written estimate and can help you find all of the water entry points in your home.  Contact us today to schedule your free inspection.

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Waterproofing & Foundation Specialists at Nusite Contractors Ltd
As a family-owned waterproofing and foundation repair business with over 30 years of experience in Toronto, we are proud of our work and stand by it with a full warranty. We’re a service company, working for you. We make sure our customers understand the entire building and repair process, and ensure that our work is done properly and made to last.

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