You wrote that even though the Torah writes the mitzvah of ma’ake in connection with fencing-in a roof, nevertheless, the mitzvah of ma’ake requires one to construct a fence in order to separate his swimming pool area from the rest of his backyard. I was wondering if one must also make a ma’ake for his windows in order to prevent someone from falling out of the window.
When there is a requirement to construct a ma’ake, the height of the partition which is required is ten tefachim which is at most one meter high. Therefore, for windows which only start at a height of a meter or more there is certainly no requirement in the context of the mitzvah of ma’ake, because there is a wall under the window which is a meter high and thus serves as a ma’ake. Therefore, your question applies only to windows which begin below a meter.
The issue was first raised by the Eimek Brocho. He wrote that one is required to construct a ma’ake in this situation. This means that one is required to construct some kind of barrier up to the height of a meter which makes certain that one could not fall out of the opening that exists when the window is open. He argues further that even when the window is closed one does not satisfy the requirement to erect a ma’ake, because the halacha is that the barrier must be strong enough to allow one to lean on the barrier and glass does not fulfill that requirement.
Many poskim noted that this is not the common practice and therefore they tried to justify common practice. Furthermore some claim that the Chazon Ish maintained that one does not have to construct a ma’ake for a window.
Rav Moshe Sternbuch (Teshuvos Vehanhogos 1, 848) argues on the claim that glass does not fulfill the requirement of a ma’ake because it is not strong enough. He argues that the reason a wall that is flimsy is inadequate is that we are afraid that someone will lean on the wall thinking that it will support his weight, and since it is weak he will fall out of the opening together with the wall. However, when people see a glass window they know not to lean on the window and therefore there is no danger of falling out.
With a similar argument, Rav Moshe justifies relying on a window which is open. Even though in this situation there is nothing to physically prevent one from falling out, however the existence of a visible window structure reminds one to be careful and not to get too close to the opening.
These arguments are somewhat difficult. First, there are little children who don’t think about windows and can easily fall through. Second, even adults can become preoccupied with something and not exercise proper caution.
This is similar to an argument which many had with the Chazon Ish in a different situation. The Chazon Ish (Lekutim Choshen Mishpot 18) claims that one is not required to construct a ma’ake around a balcony that projects out of the facade of the building since people are careful when walking on such a balcony or roof to keep their distance from the edge. Therefore, on a roof where the Torah required a ma’ake we must construct a ma’ake. But this type of balcony is not included in the Torah’s requirement and does not require a ma’ake.
However, many including the Steipler (printed in the Even Tsion) disagree with the Chazon Ish’s ruling and require a barrier around this type of balcony. Their argument is that the Torah requirement to build a barrier around one’s roof stems from the Torah’s concern that one will fall from the roof. Even though people are aware of the danger that they may fall from the roof, the Torah requires us to take into account the fact that people sometimes become preoccupied with their activities and don’t think about the danger of falling. This would also explain why even though the Chazon Ish ruled that one may rely on an open window, others could disagree.
Rav Chaim Kanievsky (Maseches Mezuzo) also addresses this issue. He says that even though one may not have any gap in the barrier surrounding a roof, one may have a doorway. He considers the window as being similar to a doorway. The argument is quite similar to the argument of Rav Moshe Sternbuch and again is quite strained.
Another poseik who discusses this issue is the Betzeil Hachochmo (4, 114). The questioner mentioned that there is a dispute if one may have a gap in the fourth wall of a roof. The Da’as Kedoshim is lenient and the Lechem Hapanim is stringent. The Betzeil Hachochmo brings proof that four complete walls are required. However, he suggests that perhaps one may be lenient with a window if the opening is narrow enough that if someone does start falling out of the window, he can still grab onto the sides. He notes further that it is rare for adults to fall out of windows.
It should be noted that even though these poskim argue that perhaps a ma’ake is not required, they all agree that one has to ensure that no one, including an infant, will fall out of an open window. This is based on the continuation of the pasuk, which states that “one must ensure that no one will die because of his house.” One difference is that when the latter is the source of the requirement to build, one does not recite a brocho. A second difference is that if there are no infants who frequent the house, one may be lenient and not construct anything.
In conclusion: While there are poskim who require a formal ma’ake, the custom is to be lenient and there is justification for the custom. If there are very young children around one must ensure that in any case they won’t fall from the window.