I wanted to sumarise why I want buillding a reptilarium with enclosures arranged as boxes:
1.Cheaper to build (one interenclosure septa for two adjacent enclosures)
Not really.
2. For more natural light and reptiles to get used to (as it is case in the wild, and without a lot of, or many-hours used, artifitial lights in blue or purple nuance)
Blue and purple???!
3. I don't like to use concrete/blocks for entire walls/roof, thus what other material can be used apart from plastic panels, glass and metal/wood construction (skeleton) and maybe low wall of rocks and concrete;
What you don't like isn't relevant if the material in question is the best option.
4. Please note that boxes are enclosures with the sizes of bathroom, small bedroom with heigh of 1.5 do 3 m.
...which is not very practical for various reasons (arboreal elapids)
5. The construction can be removeable;
...safety?
6. Better warming in cold months due to glass-garden effect;
And greater heat loss...
7. Removeable by hand, roof blocks for enabling direct sun light to reach to the reptiles;
So that they can escape?
In a nutshell, your options are greatly influenced by the local climate and the species you want to keep.
If you live in a (sub)tropical climate, you could keep various tropical species outdoors all year long in secured outdoor enclosures (granted that the local government isn't afraid of your reptiles escaping and becoming invasive species).
If you live in a more temperate, seasonal climate, you won't be able to keep tropical species outdoors most of the year. You can offer temporary outdoor exhibits to some of them, but you will have to take them indoors or offer them indoor facilities (like isolated, heated glasshouses for tortoises). As for reptile species adjusted to colder climates (such as various
Vipera species), I'd actually recommend to keep them outdoors if you can provide adequate and secure hibernation options.
For Macedonia, this would imply that you could keep local reptile species as well as "exotic" species such as Northern Pacific rattlesnakes outdoors most of the year, hibernation options provided, and subtropical species such as larger tortoises, chameleons (in gauze cages) and even some croc species outdoors during the warmer days (weather-permitted) with access to heated indoor enclosures.