Why does atmospheric pressure act not only on the street, but also under the roof of the house?

The air mass of the open space of the Earth fills all structures, including houses, which are a kind of communicating vessels, they are not airtight – air penetrates into all rooms.

The pressure will be the same throughout this space, including under the roofs of our houses, in our apartments.

In order for the pressure to differ from the external (atmospheric) one needs to make special efforts – for example, to ensure the tightness of a certain room and pump “excess” air into it (the pressure will increase in comparison with atmospheric pressure). Or, on the contrary, pump out part of it (in this case, the pressure will drop).