Buildings once were constructed over cellars. Cellars were dank, dark places where coal was stored. People never intended to live in cellars. Now we have basements that have pool tables, media centers and playrooms. Cellars were easy to construct—rubble, stone, bricks and sometimes block. If they became wet or were damp, so what? Basements are different. They are not easy to construct if we intend to live in them. They need to be dry, comfortable and keep contaminants out.