You are creating a problem which is unnecesary - the timber will rot -
especially if it's only half an inch thick, and within a few years it will
be gone, leaving gaps which the GH will slip into...simply use bolts or
screws direct into the concrete if you wish to fix it down, although it can
never blow away once glazed anyway.

Where are you living?
Here every winter we have winds gusting to at least 80mph, last winter
3 lots to 98mph (We can see the Mumbles light house from here and are
450ft higher than they are, and the met office record wind speed
there).
There is no way a glasshouse would stay put if it wasn't anchored
firmly to a good heavy base.
Bolt the house to the concrete, with just a damp proof membrane to
keep the aluminium off the concrete, better to be safe than sorry.

David Hill
Abacus Nurseries