A Wet Basement

I shouldn’t have been so naive. All of the signs were there. There was the drain hole in the center of the concrete floor. There was the iron rust stain on the surface of the floor that trailed from the furnace to the drain hole. And then there were the patterns in the thin layer of sediment covering the floor that, as a geologist, I should have recognized as evidence of flowing water. Yet, I still believed the seller’s agent when she told me during the pre-closing inspection that the basement did not flood and that a wet mark existing on the basement floor that day was due to a misdirected gutter downspout. Not to worry, she said. Correct the downspout and the basement would be wet no more.

I did have reason to believe this. In the house that we are moving from in northern New Jersey this was indeed the case. Water did enter the basement of that house whenever the gutters were clogged or water from the downspout discharged too close to the foundation. Simply adding some black corrugated plastic pipe to the end of the downspouts to direct water away from the foundation and keeping the gutters free of leaf matter effectively took care of this problem. By properly maintaining the gutters and downspouts, that basement remained dry for many years, even during severe nor’easters and hurricanes.

Unfortunately, this was not the case with the basement of the Neebor Lee house. Soon after the closing, coincident with the first rainstorm experienced while living in the house, water again entered the basement and ponded up to about an inch in depth on the concrete floor. No sweat, I thought. I drove over to nearest home improvement store to purchase black corrugated plastic pipe and used that pipe to direct the water from the downspout nearest the basement away from the foundation. This seemed to solve the problem as the water level dropped and the basement dried out. However, as I found out later, a dry basement could not be sustained by simply connecting a plastic pipe to a downspout. 

I didn’t see a wet floor, at first, but the evidence was certainly there. Because the entrance to the basement was through an exterior bulkhead door, I generally did not wander around outside during rainstorms just to inspect the basement for water. Rather, the evidence that I would see was secondary, long after the rain had stopped. In particular, I would continue to see changes in the patterns of the sediment layer covering the basement floor. It was from these observations that I started to suspect that perhaps not all was well.

Then came our first winter, and an uncharacteristically heavy snowfall. This was followed by a late winter thaw that on one particular day was accompanied by a heavy rainstorm. It was in the middle of this rainstorm that our furnace had suddenly gone out. To investigate the outage, I put on my boots and went outside to the basement’s entrance, opened the old wooden bulkhead door, and started down the steps. To my horror I found water standing three feet deep in the basement. The level had risen so high, in fact, that it had flooded the furnace’s control panel and shorted it out thereby shutting off the furnace.

In a near panic, I ran back out to the local home improvement store, which was quickly becoming my friend, and purchased a utility pump and a hose to reverse the rise of the water that was entering the basement. At that point the flooding was consuming my furnace, my water pressure tank, a water treatment mixing tank and an heating oil tank. I attached the hose to the pump, ran an electric extension cord from an outlet located inside of the house and placed the pump on the basement floor. I ran the pump overnight and by mid-morning of the next day the water was pumped down so that only a few inches remained. By that afternoon, the control panel on the furnace had dried sufficiently enough that I was able to restart the furnace to bring heat back into the house.

With the crisis averted, at least for the moment, it was time to develop a permanent solution to the flooding problem. My son, who is an attorney, suggested that I file a lawsuit against the former homeowner for not properly disclosing the flooding problem. Had there been significant damage or costs associated with correcting the problem, litigation certainly would have been a path worth pursuing. However, there was no permanent damage caused by the flooding and the fix was not expensive. Therefore, rather than litigate, I opted to invest in about thirty feet of PVC piping, a sump and a sump pump so that I could install a permanent dewatering system in the basement. The cost for all of this was about $200. I ordered the sump pump online and visited my friendly neighborhood home improvement store to purchase the sump and PVC piping. I also rented a jackhammer and that following weekend with the help of my attorney son, who traveled up from his home in Washington, D.C. to lend a hand, we went to work.

A common mistake made by homeowners performing their own renovations, whether the home is young or old, is to assume that a project they are about to undertake would be uncomplicated and fast to implement. As I discovered all too often as an owner of two previous homes, nothing can be further from the truth. This was proven once again in the basement of the Neebor Lee house. Relying again on my geologic expertise, I expected that once we had jack-hammered a hole through the concrete we would encounter soft natural alluvial sand, silt and clay that would be easy to excavate by hand. After all, we only needed to excavate a relatively small hole to a depth of four feet. I expected this work to require no more than one afternoon to complete.

The stones removed from the sump excavation were later used to create a small wall to hide metal flashing installed at the base of the Servant House.

After two days of excavation, and near exhaustion, my son and I had only excavated the hole to a depth of two and one half feet. Rather than natural alluvial sand, silt and clay, we instead encountered cobble-sized stones that were laid out in an imbricated pattern long ago by a prior homeowner, perhaps during the original 1785 construction. The total thickness of these stone layers was at least the depth of the excavation and we had not yet found the bottom. It would appear that prior to the pouring of the concrete floor, which according to house records occurred in 1903, stone was placed to serve as the basement floor. It makes sense that the original basement had a stone floor since a floor of the natural sand, silt and clay in a perpetually wet basement would have been a mud pit.

We reached a point of diminishing returns at a depth of two and one half feet. The stones at that depth were submerged and held tightly in place by the interlocking manner of their placement. Despite using a long pry bar and the rented jack-hammer, we were unable to displace any more stones. We stopped all further attempts to deepen the excavation and opted instead to install the sump at the depth of refusal. That meant that the top of the sump would not be flush with the surface of the concrete but rather would stick up above the concrete floor. Although not ideal, after two days of exhaustive digging and getting pretty much nowhere, I was okay with that. Further, the sump was not placed in a location that would experience much traffic and, thus, would not be in anyone’s way.

The top of the sump could not be installed flush with the ground due to the stone subfloor encountered below the concrete.

With the excavation completed, at least to the extent possible, I drilled holes into the wall of the sump to allow water to enter it, wrapped the sump in filter fabric and then submerged the sump into the excavation, leaving the top to stick up above the concrete floor. I then poured medium sand in the annulus between the filter fabric and the excavation sidewall and installed the pump inside the sump. This was followed by assembling the PVC piping to carry the water outside the basement. For good measure, I connected the previously purchased black corrugated plastic pipe to the end of the PVC pipe to convey the extracted water far from the foundation. The result is that I now have a dry basement that remains dry even during the worst of the rainstorms. However, whenever it rains, the pump works hard, pumping several gallons of minute during periods of heavy rainfall. It appears that the water is entering beneath the basement floor from underneath the natural stone foundation, with the thick imbricated layers of stone acting as a prolific aquifer. Some regrading of the land surface outside the basement may help further to reduce the amount of water that floods the basement, but the general topography around the house would limit the effectiveness. We would instead need to rely on the sump pump to maintain a dry basement.

Of historical interest, besides the stone construction of the basement subfloor, were the broken pieces of pottery that we removed from the excavation along with the stone. We didn’t notice them at first, but as we dumped buckets of stone outside the basement’s bulkhead door we began to encounter them. Two types were of pottery were excavated. One was a thick red material with glazed pattern on one side. The other was cream in color that, when certain pieces were re-assembled, revealed itself to be a plate. We are unable to determine the age of the pottery, but we can certainly date them to a period prior to 1903, which is when the concrete floor of the basement was poured. One could imagine 18th and 19th century farm-family occupants working in the basement and dropping plates or flower pots onto the stone floor, with the broken shards falling down between the stones where many still remain today and will likely remain for perhaps the next millennium as long as the house continues to be maintained.

Pottery shards that were removed from the sump excavation.