I sealed a crack in my basement wall, about 10" from the floor upwards.....I first opened the crack to about 3/4" by 3/4 deep with a grinder and masonry wheel/chisel, then cleaned it thoroughly. Dampen the surface. Next I mixed up a small quantity of Xypex slurry which is a crystaline style cement powder that penetrates into the existing concrete. After that, I mixed up some hydraulic cement to fill the crack and after it dried for a day or so, I "painted' it over with a coat of more Xypex slurry. It's held up well for the last 3 yrs....I would say that the epoxy or expanding foam type is probably the better way to go, but it's much more costly and imo a bit difficult for the diy'er. Having a clean crack(!!) is important to get a good bond of whatever you use. I'd also give one of these basement sealer guys a call(expanding foam/epoxy) just to find out what they charge...probably a little pricey, but they should have a lifetime guarantee.
