Unfortunately our garage has a down hill lead in, and a lovely level concrete floor. Every time it rains water comes in under the roller doors and floods across the floor making a mess and wetting anything stored on the floor.. I did dig out a small ‘ditch’ across the entrance and put in a heavy duty plastic drain that can be driven over but it hasn’t stopped the flooding. Wondering what else I can do to stop water entering? Wondering if building up a concrete ‘hump’ just inside the roller door might work? If so, how could I do that?