If you can provide positive slope so that water drains away from the structure, avoiding ponding water, rubber membrane might be an option. How are you planning on making a water tight transition against the wall? Use the accessories for making lap seams available where you buy the material. You will need cleaner, primmer and seam tape.
Remember,asphalt products are not compatible with rubber membrane. If you do put down sleepers, cut some slip sheets from left over material to layer in between the sleeper and the rubber. Rubber will shrink as it ages, so allow for contraction of the material.