Expert: Daniel G. Blum - 9/22/2006

Question
Hello Daniel -
Thank you for your time!  I just purchased a home and I'm having a issue with my basement.  It is not finishable but there is a room (14x14) with 6.5 high ceilings. The house is below the road so we have a lot of underground water coming towards us.  There is a "french drain" inside the room which runs into a sub pump.  
We never have a problem with water on the ground, but it is coming through a wall (puddle on ledge all the time).  I had a company come in (Mid-Altantic Waterproof) and they can fix it for $10,000.  Now this is my first home - so I have no money since all went towards down payment.  What can I do to lessen the pressure on the other side of the wall.  My main concern is that the pressure will build up to the point that the wall (where water is coming through) will crack and collapse.  Everyone is telling me "just use drylock" but I feel this does not fix the real problem. HELP... What can I do?  The house is 50 years old with cindor block fountain.

Answer
Matt,

I'm glad you asked.

It sounds like you live near Washington because Mid Atlantic is a well known basement waterprofing company in the area.

First, I agree that Drylock does nothing and is a waste of time for the type of problem you are having. On the other hand, there is no reason to be concerned about the structure unless there are unusual visible symptoms on the foundation wall, such as cracks over 1/8 inch, visible bulging or leaning of the wall, or tearing of wood, drywall or other structural components immediately above or surrounding the wall. The solution that Mid Atlantic usually proposes may help a little, but you are spending probably three times the amount that is needed to cure the problem.

The most effective (and incidentally least expensive) method for reducing the water seepage is to prevent rain from entering the soil in the first place, in the region near the wall in question. This can be easier than it sounds. The first step is to make sure that the rain is effectively being collected in the roof gutters and is being discharged at a point at least six feet away from the house. If your downspouts empty out any closer than that, then get some 10-foot extension pipes which are made for this purpose at the hardware store. They are black, plastic, corrugated semi-flexible pipes that you stick on the end of the downspout to extend the flow. They can be laid on the surface or buried just beneath the surface (you will want to be able to dig them up after several years if they get clogged with leaves.) The important thing is that they allow the water to flow by gravity to a lower part of the yard.

The next thing to do, if you have not already done so, is to create a "swale" or shallow valley approximately four to six feet away from the foundation on the uphill side. The reason you need a swale is that you are going to have to create a slope downhill away from the house for four feet, then the land is going to slope uphill again. The downhill portion should have an incline of one inch per foot and should be composed of a layer of clean fill dirt with a high clay content. The soil in this incline must be tightly compacted by tamping. The swale is contoured in such a way that water running toward the house will be diverted sideways around the house to a lower portion of the property.  The slope should be maintained in place with grass or another suitable ground cover. You can do all this yourself or hire a residential drainage specialist. (Tell me where you live and I might be able to refer one.)

Once you have done these two steps, you should notice a decrease in water seepage that you described. The decrease should be anywhere from 80 percent to 100 percent. If you have done everything I suggested and are still having a problem, then the best remedy is to either ignore the problem and do your best to collect the water that has seeped in, or to install an exterior waterproofing system. The ususal cost for this is about $12,000-$20,000, but it will be more effective than any other method. I would never recommend this for a basement that was not designed to be a living space. It is more like a cellar, and some dampness can usually be tolerated.

The thing that concerned me was not the water but the "ledge" you mentioned in your message. If you have a ledge around your cellar, than it is not a basement at all but rather a dug-out crawl space. This can be done properly, but more often than not, it is not done correctly. Even when it is done correctly, it is impossible to waterproof this type of construction, and no effort or money should be invested in waterproofing it except for the exterior drainage improvements I mentioned in the beginning.

If you ever decide to dig out your basement and underpin the foundation, you will have to install better waterproofing at that time anyway, so there's no advantage to doing anything further right now.

If you'd like more specifics, tell me your location, and also some more details about the existing contours of the yard, how far your front door is below the street, How far away your front door is from the curb, whether the back yard is lower than the front door, the age of the house, and a description of what normally happens to rain that lands on the house. Also whether you get any water symptoms during dry weather, and if it is associated with rain, the time elapsed between the onset of rain and the appearance of water in the basement.