Roof Water And The Basement
Before anybody quotes interior waterproofing on a Toronto basement, the roof water and the grade should be looked at, because that is frequently the whole problem.
Short answer
The roof delivers a very large volume to a small number of points. If those points discharge against the foundation, the backfill saturates and the water finds any crack, form tie or window well. Fixing the eavestrough, the downspouts and the grade is the cheapest thing on the list and should come first.
The order to check
Are the troughs actually working, or overflowing in a storm and dumping at the wall. Watch them in rain rather than inspecting them dry.
Where does each downspout discharge, and how far from the building.
Does the ground around the house fall away or back toward it.
Is there a window well, and is anything discharging into or near it.
Are there buried extensions, and do they actually still work — which is the invisible failure.
And only then: the foundation itself, the weeping tile, the sump and the interior options.
Watch it in a storm
Every diagnosis here happens during rain. A dry inspection shows you the configuration; a wet one shows you the behaviour. Go out in a real downpour with a coat and watch where the water from each downspout actually goes, and whether any trough is overflowing. Twenty minutes answers most of it.
What the cheap fixes are
Clear the troughs and the downspouts, which if they are overflowing is the whole problem.
Extend the discharges well clear of the foundation onto ground that falls away.
Add a downspout where a run is overflowing because it has too few.
Correct the grade against the wall, which is soil and labour rather than construction.
Fix or remove a failed buried extension, and keep the discharge visible so a failure is noticed.
And cover or redirect anything discharging near a window well.
When it is genuinely not the roof water
Water entering below the slab level or coming up through the floor, which is a groundwater or sewer question rather than a surface one.
Water appearing in dry weather, which means groundwater or a plumbing leak.
A backup through a floor drain or a fixture, which is the sewer and a different and more urgent problem.
Water across a whole wall uniformly, which suggests the drainage system rather than one discharge point.
Efflorescence and damp with no event, which can be hydrostatic.
But even in those cases the roof water and the grade get fixed, because an interior system working against saturated backfill is working much harder than it needs to.
Common questions
Could my wet basement be the eavestrough?
Frequently yes, and it is the cheapest thing to check first.
How do I diagnose it?
Go outside in a real downpour and watch where each downspout discharge goes.
Should I waterproof the basement first?
Fix the roof water and the grade first. It is far cheaper and frequently sufficient.