A corner shower pan can be built from concrete, although they are not the most visually appealing shower pan. When creating your concrete corner shower pan, ensure that it slants towards the drain. You do not want to feel like you are showering on a hill, but a slight decline in the direction of the drain ensures that you are not left with standing water. Rather than using water to mix the cement, use a strength enhancing latex additive due to the thinness of the base. Test the shower pan for leaks by plugging the drain and filling the shower base, then check to see if the water level drops.