We have water coming in on a basement wall located directly under our front porch stoop. Tried crack injection, that didn't work. Replaced stoop with new concrete one and did waterproofing at that time from the outside. This included sealing a crack from the outside and covering it with a membrane (can't remember the type of membrane). Any suggestions as to where the water under the stoop could be coming from? We are mystified and can't figure it out.

You say the water comes in "on the wall". How high on the wall? Where on the wall relative to the bottom of the stoop foundation? When you applied a waterproof membrane, did you apply it for the full height of the foundation from sill plate to footing? If not, where is the water entering relative to the membrane?

What may possibly be happening is that the stoop (both old one and new one) is causing a lateral load on the foundation wall, causing it to bow just enough to crack and admit water. the crack may be visible on the outside and invisible on the inside. When a load is placed on soil, it is assumed that the load is carried at a 45 degree angle from the bottom of the foundation in all directions, so some of the load of the stoop is perhaps pushing against your foundation wall. If your foundation wall thickness or reinforcing (if any)is marginal, this could be causing a crack and thus a leak.

What is the height from the basement floor to the outside grade, and how thick is your foundation wall?

I don't know all the anwers but here are some of them: the membrane was only applied under part of the porch (dumb I know) where there was a visible crack from the exterior. The walls are about 9 feet high floor to ceiling. I don't know the thickness fo the wall. The wall by the way is concrete. If the problem is as you suspect, how do we fix it.

Is the concrete stoop a one-piece precast concrete stoop?

I'm afraid you won't like the answer, but I think the only course of action is to remove the stoop if possible, expose the foundation wall in that area and maybe a few feet to each side, and see what you see. There may be a new crack. There may have been another crack that you didn't see the first time you tried to fix the problem.

If it's a precast stoop, maybe they hit the wall with it while setting it in place. Maybe heavy equipment drove too close to the wall. At this point, it could be anything. If the wall is indeed nine feet high, maybe it's not thick enough or reinforced well enough for that height, if it's reinforced at all. Is there a door or a window where you can determine the wall thickness?

How many steps are there going up to the stoop? That will give a rough idea of how much earth is against the wall. Is there a roof over the stoop, with posts coming down onto it?

This really needs some careful on-site examination to be able to narrow down the possible causes and then suggest solutions. The best I can do now is a wild guess, and we don't recommend spending money based on wild guesses. A key piece of information is exactly where on the wall the water is entering. Unlike a block wall which has hollow cores, a concrete wall is solid, so if water appears here, there's pretty much got to be a crack on the other side of here. Oh, does your wall have rod holes (where steel rods held the two sides of the forms together when the wall was poured)? If so, might one or more of them be leaking? If so, that's an easy fix, and can be done from inside.

More information needed. Do the best you can, and we'll see what we can figure out.

It is not a precast stoop. They used forms to pour it. It is just one step up. There are posts over it for a metal roof. My best guestimate (using the tape measure) is that the wall is around 8 inches thick -- at least that is the approximate thickness of the door frame. The weird thing is that the stack line goes under the porch and that is the area they sealed around by using sometime of tar plus membrane. Thanks for the help.