Broken ejector pit and water under concrete slab
We just moved into a 1950s split level that was renovated and then flipped. Cosmetically, the house looks great. But as we’ve been living here a few weeks, some major issues are presenting themselves. One is that the ejector pit in the basement was filled with black water and wasn’t emptying. The water was well above the pipes and the plumber said that dark water was sitting just under most of the concrete slab. We got a new pump installed and the water level went down and now the water is clear. The brand new carpet was starting to smell so we pulled up the carpet and foam pad. The concrete seemed dry and the wooden tack strips were in tact and not moldy. But…. I am super allergic to mold and my body has been reacting as if there is mold down there. In addition, there are a lot of cracks in the concrete slab. Is it possible there was mold there despite no obvious moisture and no visible mold? And if so, how do we even clean down there? I can’t walk down there or near there at this point without getting sick.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
The first thing I’d check is that the ejector pit is sealed. If it wasn’t sealed properly after the pump was replaced, it could be leaking sewer gas into your basement which might be what is making you feel sick when you’re down there.
You can clean the concrete with a bleach solution to kill any mold. I’d expect you’d be able to see any mold though. If you’re worried about something seeping up from under the concrete, you could try a penetrating concrete sealer or an epoxy coating, but that can create new problems (the coating can bubble up) if you have some deeper underlying problem.
Bill
If you have a pit in your basement then there is water in the ground that can leach up into your floor. Monitor the pit to see how fast it fills. Cleaning with bleach as Bill suggest will help but if the water is constant the problem will be constant. I'd do a quick percolation test of your yard, simply make a hole and pour some water in and see how long it take to drain to determine how wet your yard is then take it from there to determine if you need either outside or inside perimeter drains to keep water from entering under you basement floor.
Tom, the OP is talking about a sewage ejector pump, not a sump pump.
For the OP: If you are getting mold symptoms downstairs, it is also possible that the mold has nothing to do with the ejector pump. You might have mold growing behind the finished walls in the basement. Regardless of where it is, you've got to find it. If you are reacting that badly now, things may only get worse over time. You should find a good local moisture/mold investigator to do a thorough investigation of the basement. Note that this is not just some guy who does mold testing. This is some guy who will apply building science and use appropriate equipment to find the moisture source for the mold and the cause(s) of mold growth as well as the actual mold itself.
Peter if it were a sewage ejector as you say it wouldn't be just a pit. It would be a self contained, sealed unit and be full of human excrement and toilet paper and would smell of human waste. If you read the posters comment below he/she mentions the water level is now normal to low after fixing the pump, so obviously visible which leads to it being a sump pit with water leaching into the slab.
Tom, I think you're right. Her description of "black water" confused me. Might just have been stagnant/dirty.
I had a guy out here on Monday. Results showed Pithomyces elevated levels and none in outdoor control. He said this mold is mostly found in wet soil, paper and carpets. He checked the water in ejector pit and it’s normal low level again since it’s been fixed. He said it will take a couple of weeks for the concrete slab to completely dry out since the water levels were so high. So now we have to deal with remediation for the Pithomyces. Thank goodness not black mold. But it’s still bothering me.
I have found pithomyces happily growing in carpet backing on a damp slab. The carpet might have to go, along with the pad. I agree with the others about just painting the floor. If the floor is too cold, using a few area rugs can be OK, and if they get nasty you can clean them or throw them away.
Putting a foam pad and carpet on concrete is iffy at best anyway, regardless of what's happening with your ejector pump. The foam -and possible the carpet also - will absorb any moisture in the slab, and since concrete is moisture permeable - meaning it's very good at transmitting moisture - any moisture in the soil under the slab will penetrate the concrete and be absorbed into the foam. Better to paint the floor and use area rugs without a foam base, which you can pick up and wash. I've seen 2x2 plywood squares on plastic standoffs that you would lay on the concrete and put the rug on top, but I'm not certain if the foam would not absorb moisture anyway.
A good epoxy will make a nice (and even beautiful — some people make art with the stuff. I saw. Children’s hospital that had epoxy floors that looked like oceans to go with their marine theme) floor and also seal the concrete. Just make sure to prep the floor properly first for good adhesion, and either do the work when you can leave the house for a few days or use one of the newer water-based versions. The solvent based epoxies can be more durable, but they smell a LOT more while they finish curing.
Bill
Epoxy is a great finish - on very dry concrete. It sounds like you have at best, moist concrete which might periodically - maybe during a storm when the electricity goes out - get wet. I'd suggest a finish that is essentially waterproof, like paint. Not ideal, but best to be prepared. Be sure that you do not have fiberglass or other types of insulation on the walls which will react poorly to moisture or water.
One of the issues is that it is very likely that you do not have exterior foundation perimeter drains. You could cut a channel in the floor adjacent to the walls and drain any water running down the wall into the sump pump, but all in all, be prepared to deal with moisture and potential water in the basement. It is still possible to have a comfortable and useable space.