Concrete is like stone in many ways, but it is man-made. Bricks, again have similarities with stone. Clay, after all, is a kind of rock, albiet a very soft one, but I wouldn't call bricks stone.
Why do you ask?
Either because he's fascinated by Polish culture and the building materials of the world, or because he's a no good troll who thinks using the word "plank" is a good way of sneering at people.