Posted by Killer Joe on October 24, 2005 at 23:59:25:
If the crack has the ability to pass water all the way to it’s lowest point, sealing off the upper half will still lead to a wet basment. The pressure is greatest at the bottom. Your foundation guy is aware of this.
As a side note, a vertical crack is usually less indicative of major foundation damage than a horizontal one. Horizontal cracks can be caused by pressure from the surrounding earth, coupled with water, that allows the hydraulic effect to make the wall creep over time. This can cause major headaches, not just water damage.
Is this a block foundation or poured concrete? If the wall is poured concrete there are expanding foams that are designed to correct the problem, if the wall is block you have a different problem. The best way to seal a block wall is to fix the problem from the exterior side. Sorry.
You are correct in addressing the drainage slope near the building. However, the water will need to drain to an area that is far enough away from the walls such that the ‘new’ pooling spot, if there is one, will not become a source for continued leaks. Distance is your friend. A lot depends on the soil type. Clay is your friend, sand can be a sieve.
As far as the tarring goes, tar becomes rigid over time. If the underlying crack is not filled a similar crack will soon form in the tar as well. Some fiberglass mesh imbedded in the tar will help greatly. If you can clean out the crack, and the foundation is stable, ie not spreading (unlikely), and you can pack the crack with tar the fix should last for years. HTH