Hi, I want to build a raised patio at the rear of my garden using railway sleepers (30cm x 1600 x 4000). A railway sleeper box effectively.
I intend to build over an existing concrete garage floor.
My question is How do I manage drainage and what should I Best fill the ‘box‘ with? If I top it with cement does it not negate the need for drainage as the water would run off? Any help / advice much appreciated