The whole area under our highset house is covered in concrete that is sloping slightly towards the front of the house. This includes about 20cm that sticks out under the back garage door. When it rains it often hits the outside wall above the back garage door or the back garage door itself. It then trickles down to the slab, goes under the door and runs through the garage space to the front of the house.
What is the easiest way to fix this? Do I get some sort of concrete grinder and fix the slope outside the door so the rain runs away from the house instead of into it? Another alternative could be to build some sort of ridge inside the door (would pool there!). What do you think.