Wonderboard

[taxpayer779]

I am ready to do a tiling project and will be laying a bunck of 1/4 wopnderboard. One side of the stuff is fairly rough while the other is pretty slick. Which side is supposed to face up?

[Matt]

Now you know why it's called wonderboard.

[Tim Fischer]

Rough side up -- helps hold the tile in place.

-Tim

[EXT]

I understand that the rough side is for thin set mortar, the smooth side is for mastic or glued tiles.