Maybe add a treated 2x6 baseboard?
Just fyi, and I don't mean to be critical, but tape will not last very long in the sun.
You probably want some snap clamps to secure the covering to the pipe, if you don't put in a baseboard. You can make your own or buy them. It is a piece of plastic pipe cut long-ways that snaps on your emt from the outside. Some people go a step further and screw the clamp down with a tek screw. Here is an example of the clamp I am talking about
:
http://www.buildmyowngreenhouse.com/...erail-2-1.aspx
I'm not saying to order that specific product. Make sure if you buy any that they match your conduit size.