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Fencing a Roof


Roofs must be fenced-in to prevent danger. Which kind of roof requires fencing? Are red plastic warning tape or “Danger” signs a sufficient protective measure? Is one permitted to access a roof without a fence? Can construction workers access a roof before the fence has been erected? Who is responsible if someone falls off an unfenced roof? Metzukei Dragot is a popular nature trail in the Judean desert that attracts many young people. Part of the trail passes unfenced cliffs — is taking the trail permitted? Is one obligated to erect a fence if only he will be endangered by failing to do so?

When erecting a Torah-mandated fence, a special blessing is recited. What are the guidelines for reciting this one-time blessing? Who should erect the fence – the owner, or can he commission a construction worker to do the job?


In this week’s parasha we read: “When you build a new house, you shall make a fence for your roof, so that you shall not cause blood [to be spilled] in your house, lest someone fall from there” (Devarim 22:8). This pasuk teaches of the obligation to erect a fence around one’s roof, and the prohibition of leaving a roof without one. This pasuk also indicates that the owner is responsible fencing the roof. One who failed to do so bears the responsibility for any resultant harm.

Different Roofs

The Rambam (Hilchos Rotzeiach 11:1) and Shulchan Aruch (Choshen Mishpat 427:1-2) rule that the Torah obligation to fence in a roof only refers to the roof of a structure intended for living quarters. One is not obligated to erect a fence around the roof of a storage building, shul, or barn. Each dimension of the house needs to be at least 4 ammos. A smaller house does not require a fence.  The Achronim (Shach, Gra Choshen Mishpat 427) explain that building a fence is linked to the mitzva of affixing a mezuza – only a house that requires a mezuza requires a fence around the roof.

Included in this Torah obligation is the obligation to build a proper, sturdy fence around a ditch that is on one’s property, even if that ditch has water in it. This obviously includes a swimming pool. Included in this obligation is removing anything that may harm another person.

This inclusion seemingly presents a contradiction – if one is obligated to erect a fence or remove all hazards from his property, why would a house smaller than 4X4 ammos not require a proper fence? Do people not fall off small narrow structures?

Walking on a Fenceless Roof

In order to answer this question, we must first present another question debated in the Achronim. The mitzva of erecting a fence educates us of the general principle of protecting one’s health. Does this suggest a resulting prohibition to walk on a roof which is not fenced-in?

The Chazon Ish writes (Choshen Mishpat, Likutim 18:2) that a since the probability of falling off a roof is quite low, there should really be no obligation to erect a fence around it. This, he writes, can be derived from the permission one has to climb on a high tree or ramp for a living, which the Gemara (Bave Metzia 112a) deduces from a pasuk in this week’s parasha (Devarim 24:15): “and he risks his life for it” – one is permitted to place himself in a slight danger in order to earn his livelihood. Therefore, when necessary, a workman may hoist himself onto a fenceless roof while exercising all necessary precautions. The Torah here is introducing an extra precaution for inhabited structures — a roof must be fenced even if it is highly unlikely that someone may fall off.

Although there is no halachic prohibition to access a fenceless roof, the Gemara writes (Shabbos 32a) that one who was in danger and was saved loses some of his merits. Although there is no prohibition involved in endangering oneself, it comes at the price of his spiritual merits – he is paid for his good deeds with physical protection in this world.

The Noda B’Yehuda, however, writes (Yore Deah 10) that one who needs to slightly endanger himself for a living is doing a mitzva, and the mitzva protects the one performing it. However, one who endangers himself just for the fun of it loses some of his merits, and his behavior is forbidden.

Unobligated Structures

In light of the above, the Chazon Ish rules that indeed, if there is no real danger of falling off of the roof of a barn, storage area, shul, or small house, there is no obligation to fence the roof. The owner of this kind of structure can fulfill his obligation to protect others with a well-placed, clear warning sign. An inhabited structure, though, even if the danger of falling off is unlikely, requires a proper fence.

Obviously, a roof that presents an imminent hazard because, for example, careless people linger there, must be fenced in properly, regardless of the structure’s use or dimensions. This follows the obligation of “you shall not cause blood [to be spilled] in your house”.

Chazon Ish – Another Explanation

Despite the fact that the Torah sees a hazard in an unfenced roof, there is no prohibition in accessing it. This, explains the Chazon Ish, is due to the fact that in a one-time walk on an unfenced roof people tend to walk carefully. Therefore, one is permitted to enter a yard with a pit. People can be careful not to fall into places or walk on the edge of a cliff. However, when people access an area on constant basis, the Torah, from the owner’s perspective, knows that there will always be someone who will not exercise the necessary caution, and fall. Therefore, although one is permitted to walk on a fenceless roof, the owner of the roof (or yard with a pit) is obligated to fence it in.

Three-Faceted Obligation

The obligation to keep one’s living area free of health hazards can be divided into three facets:

  1. Erecting a fence over an inhabited home is a fulfillment of both the positive and negative mitzvos mentioned in this week’s parasha (Rambam Hilchos Rotzeiach 11:1; Shulchan Aruch Choshen Mishpat 427:1).
  2. Removing any hazard from one’s property is included in the positive mitzva of “But beware and watch yourself very well” (Devarim 4:9) and the negative mitzva “you shall not cause blood to be spilled in your house” (Rambam, ibid, halacha 4; Shulchan Aruch, ibid footnote 7).
  3. There is a general obligation to remove all public hazards (Rabmbam, ibid; Shulchan Aruch, ibid). This is learned from the mitzva “But beware and watch yourself very well” (Devarim 4:9). The Aruch Hashulchan writes (Choshen Mishpat 427:4) that the obligation to erect a fence around a cliff or other public hazard in public property rests on the public – the city residents or local officials. No specific person is responsible for failing to erect a fence on public property, and anyone who steps up and takes care of its removal is fulfilling a mitzva.

Fence vs. Hazard

In light of the above, erecting a fence can be divided into two separate obligations: one is the obligation to erect a fence on the roof of an inhabited house; the other is the obligation to remove or fence in all health hazards. This includes a pit, pool, or roof of uninhabited or small structure.

Rav Elyashiv zt”l notes several differences between the two:

  1. Where fencing is not related to the positive mitzva of erecting a fence on one’s roof no blessing is recited.
  2. Where the fence is a Torah obligation, it must be at least 10 ammos (handbreadths) high and sturdy enough not to fall if leaned on. Where the obligation is a general hazard-removal obligation, any form of protection will suffice — including a lower, or less sturdy fence if that suffices.
  3. Where erecting the fence is a mitzva, one should make every effort to erect it himself and not via proxy. Here, the rule of “the command is incumbent upon him (the one who is obligated in it) more than on a proxy” is relevant (Ben Ish Chai, Shana 2, Pinchas footnote 4). The Gemara in Kiddushin (70a) tells of Rav Nachman who erected his roof’s fence by himself, despite it being beneath his dignity. However, where the fence is not a result of the Torah’s direct commandment one can commission a workman to do the job. The halacha of “the command is incumbent upon him (the one who is obligated in it) more than on a proxy” only pertains to a positive Torah commandment, not to preventing violation of a negative one.
  4. A roof that is only rarely used and the danger of someone falling off is minimal does not require a fence, unless it is required one by the Torah because it is the roof of an inhabited structure of the necessary dimensions.
  5. According to the Ritzva (Moed Katan 11a) one is permitted to professionally install a fence on Chol Hamoed. Although a non-professionally affixed fence can fulfill the mitzva just as well, since it is a positive Torah obligation, it is proper to fulfill it in the most professional manner. However, where the fence is not a positive obligation, it does not have the above-mentioned exception.


The Gemara (Shabbos 32a) learns from the pasuk “that the fallen should fall (from the roof)” (Devarim 22:8) that a person who falls from a roof was destined to fall. Therefore, he is called “the fallen” – he was destined to be harmed, either here or elsewhere. But since his fall occurred where another shirked his obligation to erect a fence, the responsibility for the damage rests upon the irresponsible party and he is punished for it. Here, the rule of “megalgelim zechus” comes into play – good things come about by good people and so, too, the opposite.

The Gemara also derives from this pasuk that the fact that one was in danger — even if in the end he was saved –is enough of a reason to reduce his spiritual merits. Therefore, the pasuk calls him “the fallen” even before having fallen. One who is not in danger will not be harmed unless he deserves to die, even if he lacks sufficient merit. However, one who is in danger needs to prove his merit to be saved — and if lacking it, he may be harmed even if he never sinned with a deathworthy sin.

Failing to Erect a Fence

The Chochmas Adam (introduction to Sha’arei Tzedek) instructs homeowners to be very particular in erecting their roof’s fence. In his times, it seems, people showed laxity for this mitzva. He quotes the Ari on the esoteric explanation of the mitzva: the fence around the roof does not only serve as a safety measure – it brings down heavenly order as well. One who fails to erect his fence is considered to have brought the world back to its prehistoric state of tohu va’bohu. Just as the mezuza protects the home, so too the fence directs the heavenly blessing that comes to the house and, as a result — to the world.

Railings for Staircases

The Sifrei seems to write that one is not obligated to put up a fence on a ramp or stairs. The Chayei Adam (Klal 15:24), however, explains that since leaving stairs without a rail is dangerous, erecting one is certainly obligatory. The Sifri only meant to indicate that the obligation to erect a rail at the exit from the roof to the ramp or staircase is not part of the Torah obligation to erect a fence around one’s roof. Betzel Hachochma (volume 4, chapter 115) rules that while one must certainly erect a railing on stairs and ramps, no blessing is recited upon installation.

Endangering Oneself

The Shulchan Aruch (Choshen Mishpat 427:10) writes that one is not permitted to endanger himself, under the premise that he has the right to do so to himself. One who does so is flogged Rabbinically mandated lashes. On the other hand, one who is careful to protect himself is blessed “with good blessings”. This, explains the Taz, is how the Midrash (Shir Hashirim Raba 6:1) explains the pasuk “His palate is sweet, and he is altogether desirable” (Shir Hashirim 5:16) — is there anything sweeter than this – when one fulfills this mitzva he  not only  protects himself from harm, but even earns merit for it.


The roof of a house that requires a mezuza also requires a fence. The rail must be sturdy enough to support people who lean on it. The fence must be at least 10 handsbreadths (86 cm according to Rav Chaim Na’eh, 1 meter according to the Chazon Ish). A house that requires a mezuza on its doorpost also requires a fence on its roof and the likelihood of people falling off is irrelevant to this mitzva. Nothing besides a fence should be used to protect people from danger of falling.

The roof of a barn, storage, shul, or house smaller than 4 cubic meters does not require a fence.

Although not part of the Torah obligation to fence in a roof, any hazard (including the above-mentioned exempted structures) must be fenced in to protect people from hurting themselves.

The obligation to ensure public safety rest on the public. City officials, as representatives of the inhabitants are responsible for this.

There is no prohibition to walk on a fenceless roof as long as one take the necessary precautions. This includes hiking on cliff-ridden nature trails. One is permitted to slightly endanger himself for a mitzva or in order to earn a living. One who endangers himself for no valid reason loses spiritual merit and may be harmed even if he did not otherwise deserve punishment.

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