I want to build a custom sized shower using tiles for the pan.
I do not knowthe procedure but assume there has to be some type of waterproofing membrane beneath the tile. Any help appreciated.

Jshafran

See this link:

How to Build a Shower Pan (http://www.hoagy.org/house/HowToBuildShowerPan.html)

I don't want to sound like a downer but this is no small task for a first timer. Amricca has given you the best link I have ever found for a custom pan. I might suggest you consider a Swanstone fiber glass readi-made shower pan for about $250. Swanstone Single Threshold Shower Floor (http://www.theswancorp.com/products/showerWallsFloors/singleThreshold/index.php)

See this link:

How to Build a Shower Pan (http://www.hoagy.org/house/HowToBuildShowerPan.html)

Appreciate your help. Sopunds like work for a pro!

It is not a simple task, you should consider a pre-fab pan like ballenger suggests. They are easy to install and look good.