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Leaky Basements: Why and What to Do
Posted August 27th, 2012 under renovations and repairs.
Almost any home with a basement is at some risk for water penetration. Basements are not boats, and if water is present outside, they will leak.
There are two main reasons for water to leak into the basement. One is local rainfall, and the other is underground water from far-away rain.
Underground Water
Underground water is usually not a problem so long as the water table is lower than the basement floor.
Sometimes the water table can rise if there is a heavy rain “upstream”. This will cause the basement to be wet for a short time without any local rain.
Some areas in Brampton have water tables that are at or above the level of the basement floor. In these cases, you have a damp or wet basement all the time—unless the builder installed a sump system.
If your home has underground water, there are two (and only two) solutions at your disposal.
The first is a drainage system around the perimeter of the foundation, to pull water away from the house. Typically this means weeping tiles that connect to the sewer.
The second solution is a sump (water-collection pit) with a pump to move the water either into the sewer or far enough away from the house that it won't be a concern.
Typically, builders will have installed one or the other of these systems, but if not, there is nothing stopping you from adding them after the house is built. No other solution works reliably for underground water.
Local Rainfall
Water from local rainfall (meaning near or directly over the house) will always try to find the lowest level before absorbing into the ground.
If your eaves troughs and down pipes are not doing their job in intercepting the water from the roof, rain will fall from the roof line to the ground near the basement wall, and will trickle down to the foundation, where it will either penetrate through cracks in the wall or seep under the footing.
If the ground around the house slopes inward toward the house, the water that falls on that ground will flow toward the basement wall and the same problem will occur.
You can tell that a wet basement is caused by local rainfall because the basement is consistently wet during or after a storm, but dry at other times.
The weeping tiles installed by the builder can only drain so much water into the sewer. In a downpour, water can accumulate faster than the weeping tiles can drain it. Sometimes roots from nearby trees will work their way into the weeping tiles and block the flow, further reducing capacity.
Avoiding a Leaky Basement
The most important steps you can take to prevent a leaky basement are:
- Maintain the slope of your ground away from the house (check this annually)
- Keep your eaves troughs clean and have your down spouts leading away from the house for at least six feet (and working properly)
- Maintain your sump system; check the pump at least once a year for proper operation, and have a backup pump.
- Avoid having trees growing close the house (as much as possible).
Remember, a basement is not a boat. There's no such thing as a “waterproof” basement, only a well-maintained drainage system.
Want to know more about drainage around your home? Just ask me, I'll be happy to help.
