Although water coming through a foundation crack could be either ground water or surface water, we put this under the ‘surface water solutions’ category because that is more frequently the case. Whenever possible, we recommend sealing foundation cracks from the OUTSIDE. Epoxy injection can be used on the inside when there is no alternative, but you must understand that any interior crack repair will be temporary. Regardless of what warranty some guy on the internet wants to sell you, the physics are clear. The wall will continue to move, the crack will widen, and the epoxy will NOT widen with the crack. Once that happens, you’ll have water again. By sealing the crack on the outside, you are doing 2 things different. A) you are putting the chewing gum on the OUTSIDE of the crack so that water is pushing the sealing INTO the crack. B) you are sealing the entire excavated area, not just the immediate crack sight, so there is built in room for movement. Click here to see how we perform Exterior Crack Repairs.