Before we get into the purpose of a sump pump first we should talk about why you need one. We see a lot of basements where a sump pump should be installed. When you have cracks in the basement floor and water is coming up, or if you have water coming in from all around from all four sides you might consider putting a sump pump in. Or, if your ground is all clay, there may be a reason to put one in as well.
The purpose of the sump pump is to take water from underneath your cement floor, from below. That way as the water rises it doesn't reach the bottom of your cement floor.
Essentially with a sump pump you have a basin at the bottom of your floor that water drains into. The sump pump is designed to suck that water out and put it someplace else. The water wants to take the path of least resistance, and that least resistance is in the hole that we have dug in your foundation from which the water is then pumped out.
To install one, you need to break the concrete by jack hammering or cutting it. What is very interesting is that what we find when we cut the concrete is that there is no soil directly underneath. There is usually 3 or 4 inches of air space. This is because the soil or gravel compacts down and creates this gap which is a place where water can flow to with least resistance.
Once the floor is cut we have to dig down, often 2 or 3 feet. This depends on the type of soil or what the water lines show us. Then we put a basin in and that basin has holes so the water can get into it. We put landscape paper around the basin and maybe some gravel so that when the water comes to it and brings along soil the holes in the basin don't just clog. We then put the sump pump in. I prefer a submersible sump pump rather than one that stands up out of the basin because those can fall over and become inoperable.
Then, there needs to be PVC pipe coming out with a check-valve, which is a valve that does not allow water to flow back into the basin. That pipe is plumbed outside. We recommend PVC because it won't break with the freeze/thaw cycle like black flexible pipe will. A cover is then installed for safety reasons. Often people choose a sealed cover so that radon or moisture can't get into the home.
More often than not, this is not a DIY task because it involves jack hammering, plumbing and knowledge of the water levels. For more information on basement waterproofing, contact A1 Foundation Crack Repair.