[Erwin.]

Not the best choice of the wall and floor textures, it just can't be only wood. If you'd be more realistic, nowadays gym's have strong support with floors and walls. Everything must made of concrete. And the worst thing is here, that outside walls, are looking the same as inside. You could atleast replace outside or inside walls with some different wall texture, for example ID 19447, 19449, 19454. Also the windows are required, because if i'm looking at this, it reminds me of some big wooden box.