Can a Leaky Basement Be Fixed From The Inside?

The short answer is sometimes, but in many cases, no.

Nusite has been in the waterproofing business in Toronto for a long time, I can’t remember how many failed interior basement waterproofing jobs I’ve been asked to fix, and how much money has been wasted in that way (although I’m sure it’s a big number in both cases). It’s not that the work itself was bad, it was just the wrong solution to applied to the job.  The truth is that the only sure-fire way to plug a leak is at its source, and that’s the honest truth.

However there are a few methods that could help you manage the problem from the inside. I’ll tell you about them on the basis that there’s always a reason why something seems inexpensive – but often isn’t in the long run.

Things that Might Work

The correct way to waterproof a basement is from the outside. The logic is the same as putting a roof on top of a house, as opposed to trying to waterproof the ceilings from underneath. Why’s that? The pressure of the water pooling on the ceiling boards will work its way through them, and dislodge the paint from inside. We call that hydrostatic pressure in the water-proofing industry

However even a basement that’s well waterproofed from the outside will still leak if cracks develop in the walls or floor. The same can happen if a plumber drills a hole through through the wall. In that case it’s perfectly feasible to seal the gaps with a polyurethane caulk – or epoxy filler if the openings are wider than one eighth inch.

If the moisture is permeating through the fabric of the building itself, no amount of epoxy or polyurethane (or any other product in my experience) is going to do much good for any length of time. That’s because of hydrostatic pressure, once again.

True, you could install a weeping tile around the internal perimeter of the basement and pump the accumulated water away with an automated sump pump. You could even cover everything nicely with a plastic sheet or panel. But you still haven’t waterproofed your basement.

What Should Work

Concrete, cement and bricks are made from natural products found in the earth. And water seeps through earth in no time at all. The only way to stop it leaching through your basement walls and floors is to prevent it from getting there in the first place. This implies four necessary steps:

• Lay down a waterproof membrane before you cast the foundations and the floor.

 

• Water-proof the outside of the foundations and the walls as they go up.

 

• Install an external weeping tile system to lead any ground moisture away.

 

• Manage your surrounding home and garden so that rainwater flows away.

What Definitely Doesn’t Work

I’ve also seen a great many of the things that should work fail, especially when they’re performed by someone who doesn’t have alot of experience with foundation waterproofing.

The Best Advice of All

If you have a chronic leaky basement, and there doesn’t seem to be an obvious solution.  Have a waterproofing contractor come in and give an inspection.  A good waterproofing company will bring in the necessary tools to find the real source of the leak and can give you an accurate estimate of what it will take to repair the problem.  That doesn’t mean you have to do it, but you will know whether or not it’s a waste of time trying to stop the leak from the interior of your basement.