Maasrot, Chapter Three, Mishnah Six
Our mishnah deals with other architectural structures and with whether they, like some courtyards, cause produce to become liable for tithes.
1) Roofs do not render [produce] liable, even though they belong to a courtyard which renders it liable.
2) A gate house, portico, or balcony, are like the courtyard [to which it belongs]; if [the courtyard] makes the [produce] liable [for tithes] so do they, and if it does not, they do not.
Section one: Bringing produce onto a roof does not make it liable for tithes, even if the roof is adjacent to a courtyard that does make the produce liable. While the courtyard does offer protection to the produce, the roof does not and therefore the produce is not liable.
Section two: The three structures mentioned here take on the status of the courtyard to which they are attached. The gate house is a little house in which a guard would sit to watch over the courtyard. The portico is a roofed colonnade, but without closed walls. The balcony juts out from the second story of the house. If the courtyard offers protection to the produce, then these structures do as well and the produce brought into them will be liable for tithes.