So it's possible to have 1 Arduino card and many shield link with wire to the Arduino UNO card?
This is a contradiction in terms. A shield, by definition, is made to plug directly into Arduino, no wires needed, and you may stack several on top of each other. Having said that, I'm not sure it answers the question, but I am sure you need to address the matter more deeply. I also think you need to be rather wary of using an I2C bus, as I understand it is only for use over short distances, i.e. ideal for shields but that is about all. There is also the matter of how much wiring you want running round the place. I imagine addressing the latter may be quite easy by having it all outside the building.
The simplest approach might be to have sealed modules containing sensors and an ESP8266, each reporting back to the central point via WiFi. The central point may then be a Node-MCU rather than Arduino. This solves all the signal problems, and is probably cheaper than using wire. All you need do is provide a 3.3v power bus. You may even find that batteries suffice.
My 2c for you...