Duplex Terrarium - Enclosure Plans - 3
How To Build A Duplex Terrarium - 3
Now you can take the measurements to order the glass. To do this, measure the distance between the outer track edges, then add the inside depth of the upper track (in our case 10mm)

In the case of very long terrariums like ours, you MUST measure the OUTER edges along the side walls (because the center will invariably hang lower in the middle. If you measure there, the glass will fall out!)
Now we will add our removable separation wall:
To fix the separation wall, glue a U profile to the floor, the back wall and the ceiling with silicone.

Then cut a polycarbonate sheet to fit (the fixed height should be even with the top edge of the glass track.) and glue this into the bottom profile with silicone.

The rest of the pieces will NOT be glued, so that they can be removed.
Put an H-profile on the bottom wall (When you remove the inner wall, replace this with a U profile (facing down) to cover the edge.)

The ceiling part is made the same way as the bottom.

The center polycarbonate sheet is simply slid into place.

The front edge closed off with a "U" profile.

Almost forgot: You should seal all the inner edges (especially floor area) with silicone and allow to air out well before adding the inside decoration and animals.
Then hang the doors: Slide the top edge of the glass into the inside top track, push up and in and allow to move down into the inner bottom track. Then hang the second piece of glass the same way into the front track.
The inside decoration will vary depending on what you want to keep. So I will not go into detail on that.

Attribution
Author: Martin & Andrea Dannegger
Images - © Martin & Andrea Dannegger