The laws of the week in which Tisha Be-Av falls pertain only to the Sephardic custom, which maintains that one may not cut one’s hair or wash clothes during that week, as the Mishna states (Ta’anit 26b). Ashkenazim, however, are more stringent and refrain from washing clothes from the first of Av (above, section 19). In addition, Ashkenazim and some Sephardim are stringent throughout the Three Weeks regarding haircuts (above, section 10).
A year in which Tisha Be-Av falls out on a Sunday does not have a “week in which Tisha Be-Av falls,” as the fast begins immediately after Shabbat. When the customs of mourning pertaining to the tenth of Av end, so do all the customs of mourning that pertain to the Three Weeks.
When Tisha Be-Av falls out on Shabbat, the fast is postponed to Sunday. Some say that since the ninth of Av is actually Shabbat, the entire week beforehand is considered “the week in which Tisha Be-Av falls” (Smag). Most poskim, however, maintain that since the fast is actually observed on Sunday, that year does not have a “week in which Tisha Be-Av falls” (Rosh, Ran). Most Sephardim follow this position (see SA 551:4). Therefore, they may wash clothes the entire week before Shabbat Ĥazon. However, it is proper that even Sephardim be stringent with regard to shaving in such a situation. That is, they should refrain from shaving throughout the previous week, in order to enter the fast with a recognizable sign of mourning on their faces (as explained above, n. 7). Those who are lenient have an opinion to rely on.