My new house had a crazy paving style front yard. when laid they raised the ground level covering the slate DPC and level with the air bricks making it easy for rain water to run in. There is damp on the wall and this is the culprit i suspect. The house is on a hill and if i lower the ground level of the yard it will be lower than ground level of the street so i can't run rain drainage out to the street. If i dig it out will the rain water just drain the the earth naturally or will i need some drainage? Is there materials i should use to help the drainage, like gravel or wood bark etc..?