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Leaky basement

We recently received about 6 inches of rain in a few days. We now have water leaking into our basement in several different areas. We have a sup pump installed however it seldom pumps any water.

Re: Leaky basement


Are you sure your pump is actually working? Most pumps are activated by a float device. If you lift up on the float, it will start trying to pump.

Is your pump well attached to drainage tiles? You should see round clay drainage pipes entering the well from the sides. These pipes normally are set around the perimeter of the foundation to intercept the groundwater and divert it to the pump, from where it is pumped to the outside.

If there are no pipes visible, you may simply have a pump there to avert massive flooding, rather than to keep the basement totally dry.

Where is the water leaking in from? Where the floor slab meets the walls? Higher on the walls seeping from cracks? Minor seepage can often be handled through water blocking foundation paints and hydraulic cement. However, a good sump pump with a well laid out drainage tile system is your best line of defence.

Re: Leaky basement

The pump works. It is not attached to any drainage tiles. The water is coming in where the floor meets the walls.

Re: Leaky basement

Sounds like the basement floor was poured inside after the walls went up, not as a slab under the walls. If you see an opening, try to slide a putty knife into it. If it goes in vertically it's as I thought. In that case, simply cleaning the entire joint well and caulking with a high-elastomeric caulking will probably work- after the area is well dried out. Blow the crack clean with an air compressor to be sure all the dust is gone. Don't use silicone if you anticipate ever painting either walls or floors. Don't fill any voids with grout or cement- that slab will expand and contract some and you don't want it pushing outwards on expansion damaging the walls.

If you're really lucky, on trying the putty knife you'll find something just below the visible floor surface used as an expansion joint filler, usually a black fibrous material similar to celotex. You can gouge out a small part of this and fill in the depression you create with caulking level with the floor for a much neater appearance. Use a gray caulking and it will blend in with the concrete. If there are excessive gaps (over 1/4") anywhere, get the appropriate size "backer rod" from a paint store and stuff it in until just below flush before caulking. Alternately styrofoam will work here just as well.

If that putty knife only goes in horizontally, the slab is the wall foundation and the walls are no longer bonded to it but still supported. You can caulk but it's unlikely to work well for long. That is best addressed from the outside with exterior waterproofing as anything else will allow dampness into the walls making the sealant eventually lose adhesion over time.

Let us know what you find and how well your solution works!


Re: Leaky basement

Your foundation is a moat... your house site should be a hill. Your basement was not designed to be water tight, especially when the water around the basement is until pressure of gravity. Before you spend a penny on higher tech solutions, try reshaping your lot so that the rain runs off to public property. Your problem did not just occur in time for the last rain event, so you can wait for the next event after you fix your landscaping slope. I will lay you huge odds that the problem will be fixed. As a proffesional engineer is see this problem up here in the frozen north called Edmonton, Canada, this solution has worked every time except when the house was build on an old stream bed.
Good luck.

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