Q&A from the Bais HaVaad Halacha Hotline

Crude Ohel

July 3, 2025

Q May I spread a towel to block the hot sun on Shabbos afternoon?

A One may set up a temporary barrier on Shabbos, except if the barrier is intended to form a halachic mechitzah, e.g., to enclose an area so as to permit carrying (O.C. 315:1). You may therefore hang a towel or sheet to block the sun (but not on a tree; see O.C. 336:1).

If you want to spread the towel horizontally and sit underneath it, it is subject to the prohibition of asiyas ohel (making a roof-like covering), which is a toldah (derivative) of boneh (construction; Rambam Hil. Shabbos 10:13). While the melacha deOreisa involves a permanent ohel (one that remains in place for days), spreading a temporary ohel is forbidden mideRabanan (O.C. 315:1).

A solution is to spread at least one tefach (approximately 3.5 inches) of the towel before Shabbos. Spreading the rest on Shabbos is then permitted, because the ohel has already been made, so this spreading is only tosefes ohel arai (adding to a temporary ohel; O.C. 315:4).

If you only need shade for a few moments, you may ask two people to hold the towel over you, because an ohel held up by people is not considered an ohel (Kovetz Halachos 33:16)—provided that they hold the ohel directly. If they are holding it only indirectly, e.g., with poles, it is forbidden (Kovetz Halachos 33:18).