As you may know, for the past few years I’ve been in process of waterproofing my basement. Some of the things I’ve done include:
- Adding gutters to the house
- Plugging holes in the wall with hydraulic cement
- Using 4″ irrigation draining pipes to pull the water as far from the house as possible
- Cleaning up existing irrigation drains and water paths to make a clean exit for the water
- Making some small changes to the grade of the landscape to encourage water away from the house
- Addition of a large sump pit and pump to the basement.
Last year I was unable to fully test the combination of all my efforts because it was a really dry year… well, California (specifically the Bay Area) got slammed over the past 48 hours by one of the worst storms in the last 10 years.
First thing I did when I got home from work was head down into the basement to survey the damage and take some pictures. Here is what I found (click thumbnail for larger image):
When I got down there I noticed that even though the floor was a little wet, it wasn’t flooded (thank goodness). I then noticed that the pit was about half full of water and that the water was relatively clear and not completely muddy like it was in the past. I attribute this to the filter fabric and then gravel I put in around the pit.
Next I noticed where the water was coming from. On the west side of the basement where I had chiseled out some cracks I never got around to plugging any of them. In the picture below you can see why the floor is wet in places. The water is coming through some cracks (about 4 feet high), then running down the wall, then travelling in a “ditch” along the side of the wall and onto the floor. My thought all along was if I couldn’t plug all the holes adequately I could just channel all the water along the perimeter and into the sump pit:
This is the best picture of all. This section of the basement was by far the worst. Water was POURING through the walls and I’ve even got a video of water pouring over the top of the walls. Well, click on the image below to check out how dry this portion of the basement is:
Things I still need to do:
- Plug the holes in the west wall. There are still holes / cracks where the foundation meets the wall, but I’m hoping those are minor
- Cut a hole in the cap of the pit basin to accommodate the pipe from the pit
- Finish the plumbing from the pit to the pipe in the wall
- Pour cement around the outside of the sump pit to clean up the rough edges
- Continuously monitor for new leaks and plug them
- Add an emergency water level alarm that will notify me if the sump pit fails
- Continue to change the grade outside of the basement to take even more water away from the perimeter
- Possibly adding french drains around the perimeter of the house to remove even more water
I’m really excited about how things have been progressing. I’d actually like to see the torrential floods continue so I can really put these changes to the test.
One item that is still puzzling me is the whole question around the “water table” around the basement. My dad never wanted a real pit dug into the floor of the basement because he was worried that once we had one that the water would just come in quicker and we’d be constantly pumping out water until we lowered the local water table. I’m not totally sure what to be looking for, but so far it hasn’t seemed like the pump is constantly on.
If you know about water tables or have any thoughts / comments on the above please add your comments below!
3 thoughts on “Waterproof Basement (mostly)”
Just a few thoughts on water tables. A Water table is a body of water/saturated earth under the surface. It is were people get well water. You are not going to suddenly dig into an underground lake by putting in a sump-pump, you would have to go much, much deeper. Also its not just like a clear lake under the ground, it is composed of very saturated soil. I do think you are in an area with a high water table to be having such major problems. Judging by the pic’s your house shouldn’t even have a basement, but its there, so dig as many sump-pump holes as you want it won’t make a differance. If your hole was 50-100 ft deep then you might have the problem your dad is describing, it’s hard to tell because i don’t know your location. Best of luck, looks like you need it.
Lucky, thanks for the comment! I think a major reason for the previous water problems was the poor water drainage around the property. I’ve tried to alleviate that as much as I can.
This winter (just ending) was pretty wet, and so far adding gutters, pulling the water away from the foundation with pipes and trenches, and plugging the holes in the walls has almost completely stopped the water from coming in through the walls.
When the torrential rains were really hitting us, the pump was running quite frequently, but was more than able to keep up with the amount of water entering the sump pit. What I found interesting, and would love to get answered, is this:
The sump pump would drain all the water out of the pit and then pretty quickly it would fill up about 3/4 of the way with water again. Once it hit this point it would significantly slow down and almost stop rising. I could then manually start the pump (lifting the float valve) and the same thing would happen again. Does this mean the water table / level was just at that 3/4 line of the pit for the surrounding area?
YOU DEFINITELY FOUND THE LOCAL WATER TABLE AT THE 3/4 LINE. IF YOU SET THE PUMP FLOAT SWITCH TO PUMP AT THAT LEVEL, IT WOULD RUN FREQUENTLY OR CONTINUOUSLY UNTIL YOU LOWERED THE WATER TABLE. NOT SMART.THE ONLY PRACTICAL WAY TO LOWER THE WATER TABLE IS TO BURY DRAIN TILE BELOW THE WATER TABLE THAT CAN DRAIN BY GRAVITY TO LOWER GROUND. LACKING A PLACE TO DRAIN BY GRAVITY, FORGET ABOUT PUMPING DOWN UNLESS YOU OWN A POWER PLANT OR RUN A DC PUMP FROM YOUR SOLAR CELL SYSTEM. IT’S MORE EFFICIENT THAN CONVERTING THE DC TO AC TO RUN THE PUMP.
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