Basement Flooding Prevention

I don't know of any water-seal products that would defend against water coming in from an adjoining basement. That case would seem to call for a sump with an electric pump.

The house across from me (I'm in the Bronx) has an issue with groundwater that has plagued its basement since it was built, and a sump+pump is how they deal with it, as far as I know. A friend in Queens had a French drain installed around the side of his foundation, but I don't think that's an option with a brownstone.

---PCJ

I don't know of a way to seal a basement to make it completely waterproof, but there are basement waterproofing companies out there.  Try to find a reputable one with references.  I think there are devices can be installed in the plumbing to shut off the water if a pipe breaks. If you already have a plumber they might be able to help you with that.

Sump pump is the only answer.

Channel out a good 18" or more around the entire perimeter of the foundation walls. Then place 4" perforated pipe all around the perimeter. Holes facing parallel to the floor and all with slight pitch to the sump hole. Get rid of extracted dirt and Fill around pipes with gravel.Cement and finish floor as you please. Water coming under foundation walls will weep into pipes and move to the sump hole. Sump will pump it out to wherever you tie pump outlet. I am guessing where you are, tie it into the outlet of your sewer system.

As already posted, an expensive drain system and sump pump installation with back-up is the only way to redirect the water.

The other must is to build everything with the idea that you'll get some water and keep everything above your "high water" mark. Under layout storage can be on rolling dollies off of the floor. Skirts and such not to floor level. Use flooring that can be relatively easy to replace.

Mother nature won't change. You can only redirect it.

The sump pump is really the only solution to actual water leaks as opposed to dampness, the latter can be controlled with waterproof paint to some extent along with a dehumidifier.  For leaks, the outdoor foundation could be dug if installing French drains and painting the walls with asphalt.  There are two approaches with a sump pump: the concrete floor inside would have to be broken up to install the perforated drainage pipes and stone and gravel to lead to the hole for the submerged sump pump which has an outlet to the outside.  Small weep holes are placed at the foundation under the floor to allow the water to enter where the pipes have been laid.  All of this relieves the hydrostatic pressure that water can create against the wall.  Another alternative to digging up along the wall to install pipes is drilling the weep holes where the wall and floor meet inside the basement and installing a special surface mount channel along the wall where it meets the floor to divert he water to the lower part of the basement where a small hole would be dug to house the sump pump.  The water literally runs between the floor and the channel which is cemented down and acts like an inside perforated pipe.  This is probably a less expensive alternative. My advice to anyone is to make sure your basement is completely dry before  putting anything like drywall or paneling on the walls.  Any moisture can wreck havoc with those building materials and create fungus.  For myself, I avoided putting anything on my walls, even though I do not have any leaks due to a sump pump.  What I did was buy some inexpensive drapes and installed them on curtain rods at the top of the wall.  They hang down covering the painted block wall (which has waterproof paint and top coat paint on it).  This way, there is an airspace and the block walls are covered with drapery.  What you will find is that even though your walls might not leak now, over time water on the outside can find a weak spot in the morter joints or in  cracks between the wall and floor.  Covering walls with building material can mask such defects, causing later problems.  For me, personally, I would never finish a basement as a living area.  Paint the floor with epoxy paint and get some cheap carpet sections and use the drapes once you have controlled the water leaking.   Good luck.

We had water leakage in our basement for a number of years.  I finally decided to do something about it.  Got a couple of estimates on two different proceedures.

One was to completely dig up the foundation on three sides of the home, install a new french drain system and assume coating the outside walls again with tar or whatever is currently being used.  Secondly was the interior drain method with a sump pump for water removal into my downspout where the water will flow to the street underground system.

I went with the sump pump method and had a bout 82 feet of continuous drainage material added once the concrete was broken up and removed.  One negative would be that the motor in the sump pump will eventually have to be replaced  ($12-1300.00).

I am completely satisfied with is method and was about $4,000 less expensive than doing the exterior french drain system.  I no longer need a dehumidifier which while removing the moisture only keep recirculating the stale air.

The new "Wave ventilation " system removes all moisture and send the stale air outside with no moving parts.

This may be  the way to go providing you have no wall damage.

Good luck

The only real method for busted water pipes is to keep everything up off the floor.  Seal the floor to keep dust down and put down indoor/outdoor carpeting.  Do you still have galvanized pipes or have they been replaced with copper?  Get a good dehumidifier and keep the basement at about 45 to 55%, lower is better but can run-up the electric bill.  Also, there are cheap water alarms that can be put in a couple of places on the floor, just remember to replace the batteries once a year. I would also paint all exposed cement to keep the dust down.

Dan

Thanks everyone, for your input.  It will be definitely utilized when the planning gets underway.

All items stored on floor should be on shelving, 2" foam insulation board OR platform dollies on wheels.  With basements there are always possible water disasters.  Just make cleanup easier and prevent catastrophic damage.

Anything below grade is going to be prone to flooding. I'm moving my layout into my below grade garage here in Seattle. In the 5 years we've been in our house we've had water seep into the garage through the walls following torrential downpours. I looked into several solutions but at the end of the day they were all pretty expensive and I also reminded myself that we live in a seismic zone and it only takes a fairly minor quake to put a tiny crack in the wall. Instead I plan make sure the legs of my bench work are covered with a good waterproof sealant. We already keep anything of value off the floor. 

How did the water from your neighbors get into your basement?  Are there a non-masonry wall between the units?  Hopefully, the walls are masonry. 

Fist thing to do is ensure that rain water flows away from your outside walls.  Downspouts go to drains or direct the water away from the house.

There should be a floor drain which probably goes straight to the sewer or storm drain.  It is a function of when your row house was built.  It may be interconnected to the floor drains in the other units.  The older the buildings the greater the chance that there is not a check valve in the line.  The check valve prevents reverse flow into your basement.  A plumber can scope your drain and if needed install the valve.

Your basement maybe dry but still damp from moisture coming through the walls and floor.  Their are paints and other coatings to handle this.  Others have commented on more sever mositure.

There are sensors with shutoff valves that you can add after your meter.  When the sensors detect the free flow of water they close the valve stopping the water.  You often see small versions installed on washer hoses.

A slow leak would be detected and sound an alarm.

The sump pump should have two pumps with separate activators at different levels.  The second pump kicks in if the water rises faster than the primary pump can handle or if the primary pump fails.  An alarm should sound when the secondary pump kicks in.  There should be a battery backup in case of power failure.

Indoor/outdoor carpeting will resist the moisture.  Rubber floor tiles will work too and be easy on the feet and knees.

Dust is the next villain to tackle.

Jan

Below grade spaces always have the possibility of flooding. Given you are in a brownstone, I suspect the only way to do the basement would be an interior wall french drain system, I had one put in 18 years ago and the only floods I have had were when we lost power during one of the hurricanes (I now have a generator for the pump), or once when the pump itself burned out due to the outlet getting frozen over in the winter (my stupidity, the pump itself has a lifetime warranty). It is as others describe, they dig up the concrete on the periphery of the basement, dig down, they tap into the walls to releive hydrostatic pressure, then put in the perforated pipe and gravel, and this is led to a sump. In NYC the gutters are fed into the storm sewer system, so it may be legal to feed the pump output to this (I don't know for sure, though, the contractor would know). It should stop the water you are seeing. I would also seal any cracks in the wall with hydrostatic cement and paint the walls and floor with waterproofing paint like Drylok. 

As far as finishing off the basement, it does pose challenges because it tends to be humid down there. If you are going to finish it off, it is important that insulation doesn't touch the outside walls (using foam on the actual wall then putting insulation is one way around this, or build the framing for the sheetrock off of the actual wall so the insulation won't touch). There is sheetrock now that is mold and mildew resistant (course yours truly didn't use it) that can help. 

The real key is keeping the basement as dry as possible, dehumidifiers or an air conditioner will work. The Wave system is an option, it basically is a vent fan tied to a humidistat, that creates negative pressure in the basement that draws airs via vents from upper floors (that tend to be drier), venting to the outside. It does exchange the air, but it also draws heated or cooled air from upstairs and vents it outside, so it does cause your heating or cooling to work a bit more. The other option is they have vent units that take air out of the basement while pumping in air from the outside, and through a heat exchanger heat/cool the air from outside with the air expelled from inside, which brings in fresh air , vents 'old air', and the heat loss is minimal (on the other hand, it also can mean bringing in more humid air from outside). With the wave system, one problem may be if you have things like hot water heaters or a furnace in the basement, in creating negative pressure it could suck CO back into the house, so you have to be careful with that. My basement is pretty small, and a dehumidifier does a decent job. In theory you could create a wave system out of a strong bathroom ventilator, a humidistat and opening some vents up to the upper floor from the basement for a fraction of the cost of a wave system. 

The safest route in the basement is not to finish it off, but it can be done if precautions are taken, you won't necessarily have problems with mold and such is you do it correctly (or have it done). It is a lot nicer to have it finished off, makes it a bit more pleasant to be there, but at the very least paint the walls a cheerful color and on the floor, put down rubber tiles that a)are pretty impervious to water and b)are soft on the feet. 

In the end, others are right, basements are at risk from broken pipes and other unexpected disasters, and one of the biggest things is to have things out of harms way, have things off the floor, whether it be the trains, shelves, or things like washers/dryers, hot water heaters, etc. 

Since I spent Saturday cleaning my basement up after 2.5 inches of rain....been there!!!

I am winning the fight...but still am going to have some issues. The best thing to do is plan for it.

I have a GOOD sump pump....and sounds silly but I have an identical new tested unit on standby. I have a 20 Gal shop vac that pumps water. And everything in the basement is in the large plastic storage bins for water protection. Nothing just sits on the floor....ever.

Also I have a dehumidifier that runs most of the Spring Summer Fall, (you want some humidity in Winter) and I have a good fan that pulls air FROM the basement to the outside and runs on a timer 15 minutes an hour during non sleeping hours....again not in Winter.

All are excellent suggestions, but if a sump pump is used, it only is as good as the power source for it.  Way too often, when heavy rain storms are accompanied by violent winds, power is lost and the sump pump is literally dead in the water.  To guarantee a dry basement, under all types of weather emergencies, a generator is a must.  Power doesn't have to be out for a lengthy period of time for the sump pump to be overwhelmed. Even if one has underground utilities, the electrical wires come out of the ground somewhere, and that place just may be where the storm is most violent.

A generator would be the best by far, but you can get a battery back up for your sump pump that will give you 10 hours of run time for the pump. We have added that option.  That is quite a long time and should last quite a while considering the pump only needs to operate for 30 seconds or so at a time to empty the sump. Also someone mentioned a water powered pump for back up which would run as long as you still had city water. However, I would love to have a generator for more reasons that just the sump pump.

I too have a generator but make sure it is big enough (wattage) to handle your pump....they can be big current users.

Live near O'Hare airport.

Our house was built with drain tiles and a sump well. When it rains hard its like a fire hose into that well, mostly because my neighbors downspout is pointed at our house, and their house is about two inches higher.

I have Basement Watchdog main pump, and a BW battery backed sump pump, still working since about 1995. The battery needs to be replaced every five years or so.

There exist backup sump pumps that work by household water pressure, they add a bit more water to that being drained to help pump out the water.

If tree roots clog your sewer pipe, all your hard work is for nothing.

We have a backup portable generator, Honda, it was NOT cheap. About three months after I bought it, I found a similar unit on sale for about $350, by a name brand generator company. But what was I going to do with two generators.

I installed a clear check valve so I could verify that the flapper is working, and that the pump is working too.

I do have a spare check valve and main sump pump sitting on the shelf.

Paranoia? Perhaps.

I would prevent intrusion on the outside too as much as you can. Anything pitched toward the house like sidewalk should be remedied. Roof drains pointed away from foundation.  Inside, you jackhammer floor at foundation and then install an inside drain. They make a plastic sheet super thick it covers over the wall and tucks imto drain so water flows behind it all into drain.  Then you can finish it.  Put backflow preventers on drain in floor too

A 5000W generator will run two sump pumps, a refrigerator and a couple of lamps so you don't stumble around in the dark.

Better yet, invest in an automatic whole house generator.  Sure, you'll have to sacrifice a couple of VL Big Boys, but in a multi-day outage, it pays for itself.

I've got a 10KW unit.  No extension cords, no running out for gas, no setting it up after the power goes out, starts automatically if I'm home or not.  No spoiled food.  Runs 90% of the house, including the furnace.  The first year it was installed we had a 4 day outage, the next year a 3 day outage.  Had a couple of 8 hour or so outages after that. Worth the money.

Rusty

Surprisingly this home has water issues.  (2) Sump pumps, (1) with a battery back-up and a good bit of remedial work done on gutters/downspouts recently.  New garage door installed last weekend with better sealing than the 60 year old door that was replaced. 

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Part of the problem, today, is 2"'s of rain in an hour can overwhelm just about any well intentioned drainage system.  Some where I read, Pensicola, FL got over 20" of rain in a 24 hr. period during a recent storm. 

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I do have a spare check valve and main sump pump sitting on the shelf.

Me too.

Last year I had the check valve fail. The flapper broke off, and blocked the outlet. The main pump just ran and ran. Thank goodness I have a battery backup pump that took over and sounded an alarm.