False water table in Toronto basementFalse water tables can spell trouble for your basement or crawl space, even when these areas are waterproofed. As a homeowner, it can be frustrating when water keeps seeping into these areas when you thought you were protected.  Here in Toronto, almost all homes have basements and with the weather conditions and underground waterways running through Toronto, water seeping into the basement is a constant issue for Toronto homeowners.

Sometimes homeowners think their home is sitting on a high water table, when in fact their house sits over a false water table created by loose back fill.

How False Water Tables Form

A false water table forms because of the process used to excavate for your home. A hole is dug in hard-packed soil for the foundation. After the foundation is built, soil is “back filled” around the perimeter. This fill is not as compacted as the undisturbed soil beyond the foundation area. As a result, water penetrates where it can enter easily; around your home. When it rains, or when snow melts, the water follows the path of least resistance and flows away from the hard-packed, undisturbed soil towards the looser, more porous back fill.

Diagram image of a false water table in Toronto basement

Water that has accumulated will continue to rise if water is coming in too quickly, or the real water table is full and cannot handle any more water. As water always seeks to level itself out, it presses into all the voids in the soil, under the foundation and in the foundation walls. The water will continue to climb as long as there is more water pouring in and this creates what is known as a false water table. This can happen even if your home is built on high ground as the soil around the foundation collects moisture before it has a chance to run off. In the meantime all this water exerts an incredible pressure on your foundation.

Hydrostatic Pressure

Once the false water table fills up and becomes higher than the floor, your trouble really starts. Hydrostatic pressure is 63.4 pounds per cubic foot and the water presses in all directions to find its own level. Most homeowners are not even aware this is happening until there is a heavy rainfall or large amounts of snow are melting. The area under the foundation may store up to 2500 gallons of water, but when this fills the water has to find a place to go. If your foundation has any cracks or weak areas, the water will find it and enter the lower level of your home.

Basement waterproofing in Toronto diagram of basement leaks

Clearly, leaks caused by a false water table cannot be solved with a commercial patch kit. The force is too strong. Excavation alone will not solve the problem either. You will need a system designed specifically for a false water table. This involves both water control and a method of relieving the enormous pressure that builds up against the foundation. This is definitely one problem that you will want expert help with. Failure to attend to a false water table may result in the erosion of your house’s foundation, leading to additional cracks, more damage and additional costs.

Toronto Waterproofing Experts

Contact the experts at Nusite Group for a free inspection and estimate. We use cutting edge technology to find the true source of the basement water leak, which could save you both time and money. We are industry waterproofing experts and service the entire Greater Toronto Area.

How much does it cost to waterproof my basement?  This is a very popular question and a legitimate one as the costs of waterproofing your basement in Toronto can vary widely depending on the type of waterproofing job involved as well as the size and type of foundation of your home.

Here in Toronto, most homes will have water problems with their foundation at one time or another due to the age of the homes in Toronto as well as the sometimes extreme weather.  Toronto also sits on top of hundreds of underground waterways which does not help.  Many times the homeowner calls in a professional waterproofing company after they have tried to remedy the situation themselves to no avail.

I’m going to assume that you’ve already tried diverting rainwater from your garden, checked your downspouts, adjusted the gradient away from your foundation and identified that your damp problem is not the result of interior humidity. This leaves three options open:

  • Do nothing (unlikely because you’re looking for solutions). This option is also going to become very costly in the long term.
  • Waterproof your home’s foundation from the inside by either fixing the foundation cracks and sealing it or installing an interior weeping tile system to divert water away from your basement. Fixing cracks and using waterproofing paint or sealant is usually a temporary fix as hydrostatic pressure from the exterior will eventually push its way back into the foundation.  Interior waterproofing is not actually waterproofing, it’s water management as you are not stopping the actual water leak source, just diverting the water from your basement.
  • Do it properly by appointing professionals to waterproof the outside of the foundation wall with exterior waterproofing. This is actual waterproofing as you are sealing the basement from the outside, creating an impenetrable water barrier around your foundation. This is the most expensive but most permanent solution.  Pay for quality. Fix the problem.

To help you reach the right decision, here are the average material costs of several common interior waterproofing options you may be able to apply yourself. You’ll need to factor in the cost of labour, and check how to prepare the walls first.  These are very rough estimates and every job can have unforeseen challenges that add to the overall cost.

Before You Start

Water is a persistent thing and finds its way past most things. The Grand Canyon, Ayers Rock, the White Cliffs of Dover and the Rocky Mountains are proof of this. To succeed, you must first fix all the obvious trouble spots first. Use polyurethane caulk @$5.00 / 10oz tube for cracks / gaps under 1/8” wide, and epoxy filler @ $35 / 9oz tube for the rest.

Silicon Concrete Sealer

This penetrating product soaks through the exterior of concrete and brick to create a waterproof surface. You can’t put it over paint because it won’t soak in. Use a sprayer, brush or roller. You can usually paint over it afterwards (check the label) because there’s little risk of cracking and peeling.

Average Cost: 1 gallon costs $45 and covers 200 square feet. You’ll need 2 coats.

Concrete Waterproofing Coat

This is a cement based product with special additives that sticks permanently to raw brick and concrete when fully dry. It stands to reason it won’t dry on wet surfaces without degrading, and it is unsuitable for previously painted surfaces. Apply it with a tampico brush. If you’re an artist, swirl it around to create patterns.

Average Cost: 5 gallons of dry powder will cost $45 and cover 100 square feet.

Waterproof Paint

This is not the most robust option but the simplest for the average homeowner. It’s basically acrylic wall paint except a whole lot thicker. Being paint it sticks to paint and takes over-painting too. Apply it with brush, roller and sprayer just like any other paint.

Average Cost: $35 per gallon which covers only 75 square feet (because it’s thick).

Plastic Sheets / Panels

The sheets and panels cover the walls, and channel the moisture into internal drains from where an electric pump disposes of it. This won’t stop the water from imperceptively degrading the building, but it will conceal the obvious and protect basement contents.

Average Cost: $4,000 for a 400 square foot room of average height.

Exterior Waterproofing – The Sure Fire Solution

None of the above will permanently solve damp basement problems, although silicone and concrete waterproofing may for some time if the crack/leak is very minor. There is only one solution that I’ll put my name to, and that’s an exterior waterproofing solution by excavating around the basement, membraning the walls, and installing outside soak-aways to lead the water away to pumps if necessary.

Average Cost: $15,000 to $30,000 depending on size and complexity.

This is expensive but then quality does come with a price tag. The tragedy is that it shouldn’t be necessary if the builder got it right first time. Don’t make a second mistake by throwing good money after bad. Find somebody with experience to get your basement waterproofing right.

 

About Nusite Waterproofing

Nusite waterproofing is a basement waterproofing company in Toronto.  We are a family owned business and have been serving Toronto and the surrounding GTA for over 30 years.  We offer professional work with great customer service.  Contact us today to schedule a free in-home estimate and inspection of your water leak.