I am thinking of putting a greenhouse on a balcony on the second floor of my
home. The balcony is 11’6″ x 3′ 6″. The roof begins 7′ 4″ from the bottom of
the decking.

What would the weight of the greenhouse be? What would the cost of a
greenhouse this size be? How difficult would it be to assemble 3 stories up?

The best we could fit with you is our SolarShed.

I think the SolarShed might work out perfect. Just a couple of questions:

1) Could I attach 2 sheds together? Since they are 5.5′ long, two would
perfectly fit on the balcony.

Yes you can.

2) How is the shed attached to the wall – I want to make sure that no bugs
can get in the shed.

You can use eye bolts, wood slats and or other means. Bugs are hard to keep out of any enclosure.

3) The picture on the web site shows a door inside the shed. This is exactly
what I want to do (the door would be the door to the balcony). But how is
this possible if the shed is only 6′ tall?

The door you see is only 5′ high.

So I think I have my structure choice – 1/2 of a Crystal Cave 9. Now can I
do that? Next could I lengthen it to 11′ long? If that seems like a possible
choice, then all I have to figure out is the covering.

The best we can do is to make you 3/2 of a Crystal Cave because of the connectors. It can also only be extended by 1/2 its length to 13.5′.