Many homes have a sump pump installed in the basement or crawl space. This is necessary, any time that the low point in the home’s plumbing is below the level of the sewage lines, allowing waste water from the home to be forcibly ejected by the pump, into those sewage lines. If there was no pump, then the dirty water would accumulate in the low point of the home, probably the basement.
The term “sump pump” refers to the design of the system. In a way, it should be called a “sump & pump,” as there is a sump, with a specially-built pump to eject the sewage water. The sump part is merely a basin for water to collect in, with the sump pump sitting in the low point of this basin, where it will have access to the water to be pumped out. This water may include some solids, so the pump has to be designed for it.
A sump pump installed in a basement is often installed in nothing more than a hole in the concrete floor, rather than a concrete box, specially created for it. This creates a potential access point for radon gas, which can leak in through the opening in the floor.
Radon is a radioactive gas, naturally found in the earth. Due to its light weight, it tends to migrate upwards, entering our homes and the atmosphere. The problem though, is that it is the number two cause of lung cancer in the USA. For this reason, it is only reasonable to take precautions against radon entering your home.
You can buy sump covers to put over your sump pump, but their price and their utility seem a bit out of line, especially considering that the sump cover is simple and not designed to be attractive. Another option is to make your own sump pump cover out of plywood and then use the money you saved for something more useful.
DIY Sump Cover
In order to make a DIY sump pump cover, you’re going to need a piece of ¾” plywood, preferably without voids. If it has voids on the surface veneer, putty them and sand them, providing yourself with a clean, smooth surface. This is necessary, as you need the sump cover to seal against the concrete floor of the basement.
Most people don’t bother, but I would recommend sealing the edges of your sump cover with latex painter’s caulking and coating your cover, both sides, with a couple of coats of good, heavy-duty latex paint. This will help prevent it from becoming water damaged, protecting and preserving it.
Depending on the installation of your sump pump, you may need to make as many as three holes in the sump cover. These will be for:
- The drain line going out
- The electrical line
- Your vent for radon gas
it is possible that your drain line going out is already installed beneath the floor and you won’t need to make an access for it. However, if it is coming up through the floor, you will need to make an appropriate sized hole with a hole saw in your sump cover. Use a rubber gasket in this hole, so as to maintain the seal of the cover.
You will also need to seal the hole for the power line that is providing electrical power to the pump. Standard grommets exist for this, if not in the electrical department of your home improvement center, then check the electrical department.
The sump cover is bolted to the floor, using concrete anchors. You do not need a high-strength, as the cover will not be supporting any weight. Rather, the weight will be supported by the floor.
Covering for Radon
Since one of the biggest reasons for installing a sump cover is to protect you from radon gas entering your home, you will probably want to take the appropriate action to ensure that your sump cover provides this protection. Before installing it, check to see if radon gas is a problem in your area.
You will need to do two things to protect yourself, besides installing the cover itself, if your area has a problem with radon gas. The first is to seal the sump cover to the floor. This can be done by the installation of foam-rubber weather-stripping, of the type used for sealing wood windows. You will want a fairly thick foam rubber (1/2” thick x ¾” wide). It doesn’t matter if you stick it to the floor or to the plywood, just as long as you don’t leave any gaps.
The addition of weather-stripping may require you installing a few more screws, just to ensure that the cover seals all the way around. The foam rubber will fight against the plywood compressing all the way down to lay flat on the floor. The addition of additional fasteners in the middle of the long side can solve this problem.
The other thing that is necessary is a vent pipe. It is recommended to use a 4” PVC vent pipe for the evacuation of radon gas. This can either tie into your home’s other plumbing vents, if they are large enough, or it can be run as its own vent stack.
It might be problematic installing this vent stack, as the sump is often in the front of your home, so running out outside of the home can be aesthetically displeasing. If that’s the case you are dealing with, and you can’t run the vent pipe up through the center of the wall, you might want to consider running an angled vent in your basement, allowing you to run it up the side of your home, rather than the front.
A 4” PVC pipe is needed, so that wind passing over the top of the vent will create a vacuum, drawing the radon gas up the pipe, so that it can be vented into the atmosphere, where it will not be dangerous. If you use a smaller diameter pipe, there will be less of a vacuum, reducing the effectiveness of your vent.