That gap you see between the wall and floor is caused by the way foundations are built. The walls are poured first, then the floor is poured after. This results in a small gap between the walls and floor. What if you see water coming up between them? This indicates that the drain tile around the foundation that is put in during the build, is not working efficiently. It could be clogged up, crushed or has been improperly installed in the original construction. So why not just seal this up like you would a crack in the wall? An injection might help in that immediate spot, but the leak will appear right where you stop. So why not inject the whole parameter? The hydrostatic pressure that builds up around the foundation will eventually force its way in. What is the answer to this then?: Chances are you will need an interior drain system installed.