When we want to talk about going or being upstairs or downstairs, we're not going to find a direct translation in Italian. We have to use other words.
No, vado di sopra a prendere la borsa e le chiavi e scendo giù subito.
No, I'm going upstairs to get my bag and the keys, and I'll be right down.Play Caption
If you are upstairs and want to go downstairs, you could just as well say,
Vado di sotto a prendere la borsa...
I'm going downstairs to get my bag...
When we are talking about the other room, or another room, or "over there," then we use the same little preposition di (of, from), but we use là (there) instead of above or below.
Vado di là (I'm going in the other room, I'm going over there).
Pietro è di là (Pietro is in the other room).
Using the above formula to talk about "upstairs," "downstairs," or "in the other room," is one way to express this. You might also hear simply su and giù.
È su (he/she is upstairs), sta su (he/she is upstairs).
Vado su, vengo giù (I'm going up, I'm coming down).
If we imagine an apartment building where you have to go downstairs to go out of the building, it's easier to imagine the Italian use of sotto casa (right in front of the house). I may have a little market right near my house. It's sotto casa. It implies "very close by" or "in front of."
Fortunatamente ci hanno messo un bidone sotto casa.
Fortunately, they put a garbage can in front of the house.
Caption 25, COVID-19 6) La guarigionePlay Caption
Sono sotto casa tua. Scendi un attimo?
I'm in front of your house. Will you come down a moment?
Caption 30, La Ladra EP. 7 - Il piccolo ladro - Part 3Play Caption
When we want to say, "down here," or "down there," then we can use qui sotto or qua sotto. They are interchangeable and can refer to either "here" or "there," depending on one's point of view.
E qua sotto c'è il fiume Tevere.
And down there is the river Tiber.Play Caption
Infatti, vedi le strutture che sono qui sotto, qui sotto a questo monumentale... -Sì.
In fact, do you see the constructions that are down here, below this monumental... -Yes.
Caption 44, Marika e Daniela Colosseo, interno - Part 1Play Caption
While sopra and sotto with di often refer to "upstairs" and "downstairs" as we have shown above, su and giù can also be used to indicate the direction of where someone or something is or where someone or something is going. They often go hand in hand with qui or qua (here) and là (there).
Qui and qua basically indicate something that is close to the person who is speaking. Su basically means "up" and giù basically means "down." If we want to refer to something far away in an upward or downward direction, we can say, lassù (up there) or laggiù (down there).
E tu che ci fai lassù?
What are you doing up there?
Caption 8, Dafne Film - Part 5Play Caption
E poi si vede in fondo, laggiù sull'Arno, il ponte più caratteristico di Firenze, uno dei simboli della città, che è il Ponte Vecchio.
And then you can see, down there, on the Arno, the most characteristic bridge of Florence, one of the symbols of the city, which is the Ponte Vecchio [the old bridge].
Captions 36-38, In giro per l'Italia Firenze - Part 4Play Caption
Sopra and sotto are also used to mean other things, also figuratively, and hopefully, they will come up by and by in videos and lessons. Meanwhile, you now have some ways to describe where you are going or where you are in a house, or what you can see from your house or what you'll find in front of your house. As you will have noticed, there are various ways to say the same thing. Let us know if you have questions! You can write to us at firstname.lastname@example.org.