We've demolished our bungalow in order to build a new house. As the garden is large and slopes off away from the house, we want to use the broken bricks and smashed concrete to fill it in. As part of this, we want a totally flat area for our kids to play football on. Our demolition contractor says we don't need to crush the bricks before putting them in the garden. Will this work? Or is he just trying to save labour here and fob us off?