pkovo

I own a ranch home with a basement (1/2 finished ½ unfinished) that was built in late 40’s or early 50’s and have questions regarding basement flooding. For the most part, my basement is dry, and not humid. I have a radon remediation system consisting of two 4” pipes through the slab on either end of the house in the center about 24” form the foundation wall. If I get a sustained hard steady rain, I will start to hear water sloshing from the radon remediation system. Presumably, the water table is rising and I am hearing the system trying to suck the water that collects beneath the pipes.

In the past few years we have had two big rain storms in which the water table got high enough so the sloshing stopped as the water table rose to my floor level, and water started to seep in through cracks in the floor. In each instance, the timing was such that right as this happened, the rain backed off and the water subsided so I had no damage, however, I don’t want to rely on luck the next time we have one of these rare storms and I’m looking for information on a possible remedy. Worth noting, in each of these storms my neighbors fared worse than I, some getting inches of water. My downspouts all drain far from the house, and the grading is good, problem only occurs with very heavy sustained rains.

I noticed on the unfinished side of my basement there is a spot that looks like there was a sump pit that was sealed up. There is a square metal plug (cleanout??) there now, but the patched area is a circle that is about 24” in diameter. I would think for my situation a sump with a pump would be perfect to relieve the water table just in these rare instances, but my concern is the house is so old that the appropriate drainage may not be in place. On the other hand, the fact that it seems like there was one there before makes me think maybe it is. Any idea on what would have been normal construction practice in this regard for a house of this age?

Also, does the sloshing I hear from the radon remediation indicate anything? Perhaps a clue that maybe there’s adequate drainage. Assuming no special drainage is in place, if a sump was added could it be effective, or would it just be a situation where it would relieve that one specific area? Any ideas/help would be very appreciated.

inspectorD

You need to contact your remediation company. They should not have removed a pump and covered the sump pump hole without a means to get rid of any future water. You need a sealed unit sump pump installed so the radon does not come back in. They are out there. There is most likely a curtain drain under the floor with a central area to collect the water. You need to remove the cover to find out. If you do , get the pump installed. If not you have to contact a basement water systems company for the new radon drain systems. Tell us how you make out.

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glennjanie

Hello PKOVO:
I vote for "D's" remedy of a sump pump. It will be below the floor a couple of feet and will prevent the water table from rising to a trouble spot. The sump will need to be sealed and vented to the outside because of the radon.
Glenn

pkovo

Thanks for the info! By sealed up, I mean the spot is cemented over, with just this cleanout plug in the center. My guess is this was done prior to the radon mitigation as it looks old, and the mitigation was added in the 90's.

Forgive my ignorance, but what is a curtain drain? Would that be a series of drain tiles around the footer leading to a sump pit?

I would like to have a sump pit in place with a pump, and believe with one of the radon specific sealed ones it would probably be easy to tie into the existing radon pipe exiting the house. It would be a short run too. In the past, I always thought to add a pit I would also need to add some type of drainage system first to tie into the pit, which could be quite a job. However if there's already one in place, then it wouldn't seem to tough to simply add a pit/pump.

I also started poking around outside and found a pipe next to my foundation tucked under my deck on the corner of my house that looks like it was for a downspout. It seems to go straight down along the foundation and looks old (cast iron??). Could it be that at one time the gutters drained to drain tiles along the footer of the house and subsequently to the old sealed sump pit? When the house was built it had septic, but was then converted to sewer later. I can't imagine anyone would pump storm water into a septic tank, so it seems like an odd setup to bring the water in, then pump it back out. My downspouts now come down on the other end of the house and are piped to the street.

I'm going to start by trying to take out the plug once the water table is lower to see if I can tell what's there. I'll keep you posted, although my wife is due with our first child, so I probably won't mess with this right away.

pkovo

OK, so the day after my last post I tried to remove the plug...no luck. I then started to chip away at the concrete, but didn't get far. Then, the next day my daughter was born and thi sfell of my radar. Now, 10 months later and I'm thinking about it again. In the past ten months I've had no problems with water, but still would like to be prepared for the next "big" rainstorm.

More about the "sealed spot" in the unfinished side of my basement. It's about 2' from the back wall of my house, and about 4' from the end wall, so roughly in the corner. The plug is not centered, but off to the side abit. There is an old unused water hookup in this part of the basement and I believe it used to be where the washer and dryer were. I took a few pics, but it's kind of hard to tell much from them. ANyone got any ideas? I'm still thinking it could be an old sealed sump pit, and if so there may be drain tiles running to it.




I thought of another thing. Bear with me because it's a very half a$$ed idea. Each time the water table rises, I can hear the water in my two radon remediation pipes well in advance of actually being "in danger" of flooding. If the rain continues on hard, eventually the gurgling stops as the radun pits fill to the top, then it's a matter of minutes before the water will start to seep in (again, each of the two times prior I lucked out as the rain subsided right as this happened, and the table lowered.). WHat I was thinking is, in an emergency situation, what if I turned off the radon fan, cut the PVC, and pumped the water out from the radon pits? Very half a$$ed, but in theory, if the ground is porous under my basement floor, which I think it is, that should relieve the water table much in the way having a sump pit/pump would. I would have to use a utility pump and snake the house down the pipe, but I believe the radon remediation pits are generally dug about 12-24" inches deep. It would be easy to repair the PVC pipe afterwards. Hell, I could add a cleanout type plug and use some silicone caulk so if I ever had to do it again I could just break the silicone and unscrew the plug. I know it's not really a solution, but it seems like it could work in a pinch.

My other thought was, each of the two times the water table rose to the level of my basement floor, I saw water start to come through gaps all over the floor. It didn't seem like one area was any more prone than the other, it just flowed up evenly. It makes me think that the ground below the floor is probably porous enough that if I installed a sump pit, even without drain tile, it would probably work because the water would flow through the porous soil to that spot.