Your Place: Rare flood may have left lasting foundation woes

Question:

Last winter, after a snowstorm followed by heavy rain, for the first time in more 100 years, our basement flooded with four to five inches of water. Every time I would pump it out with a portable sump pump I purchased, it filled again. It took almost two weeks to finally dry up.

Our plumbing company said it was because the water table in our area rose five feet. Everyone in the area was having the same experience, so the plumber is probably right. Every time we have heavy rain now, we can see various spots on the cellar floor getting damp, and sometimes by the bilko door, it actually gets a puddle. I thought after the summer, the water table would have gone back to its original level.

The basement is unfinished, but it has workbenches for my husband's tools, and we have our washer and dryer down there. Fortunately, the heater and appliances do not sit directly on the floor.

The walls are fieldstone with some kind of mortar. The floor is about 1-2 inches of cement or some type of concrete surface. The house is on a slight rise, and we have never had any puddling in the street or yard during heavy rains or snow. Our downspouts are clear and run at least 10 feet from the house.

The house is about 130 years old, and when we sell it, we assume it will be torn down because of its age and condition, so we don't want to spend a lot of money (my husband is retired and I have about six more years before I do the same).

Any idea why the water is still appearing and what we can do? My husband doesn't think this will ever happen again, that last year was just unusual.

Answer: I hope your husband is right. I wonder if the intensity of the flooding and the water ponding in it for several weeks created damage that makes your basement more susceptible to flooding from now on.

That damage might not be readily apparent. The rise in the water table that your plumber points to might have undermined part of the floor enough to let water pool there, for example.

There might be a crack in the foundation below the soil line outside that directs water into the basement when there is enough of it and it doesn't drain properly.

In my semifinished basement, which has a sophisticated system of perimeter and french drains leading to a sump, there is, under the laundry sink, one very small spot where water from the outside collects during winter months when there is heavy rain or melting snow.

It doesn't happen in the other nine months, and the water drains harmlessly into a channel cut for it that flows into the sump.

Rather than spend a lot of money on trying to mitigate the situation, I'd keep an eye on it and keep valuables out of harm's way. You might, as my neighbors did, raise the appliances on concrete platforms to keep water from getting into the motors.

By the way, the mortar in the fieldstone walls is referred to as Irish plaster - a mixture of excavated soil and lime, I'm told - so-called because most stonemasons in those days were Irish.

Dehumidifiers. The one in our basement takes a vacation from November until April, I'm sure to the chagrin of PSE&G, and the humidifier on the furnace takes over.

But to get you thinking about dehumidifiers, Consumer Reports has compiled a list of the best and some buying tips, so here goes:

Safety 1st, Ultrasonic 360 was determined to be a "best buy" for 330-square-foot areas.

Don't buy solely by type - Consumer Reports found performance varied widely among different ultrasonic, evaporative, and impeller models.

Regular maintenance is critical for all humidifiers - even models such as the Sharper Image HD10, which claims to "prevent microbial growth on the surface of the water tank."

Regular maintenance should include changing the water daily and disinfecting the tank weekly.

Ours drains directly into our sump along a plastic gutter splash, and I vacuum the filter routinely. It works well.