Mr. Braun was renovating his house. On the ground floor he added a room whose roof provided a spacious porch for the second floor.
He discussed the plans with his learned neighbor, Mr. Adler. “Do you realize that making a guardrail, a ma’akeh, on a roof porch is not only a safety issue, but also the fulfillment of a mitzvah?” Mr. Adler asked him.
“Yes, I know,” replied Mr. Braun. “I even mentioned that to Tony.”
“Who’s Tony?” asked Mr. Adler.
Tony’s the contractor,” said Mr. Braun. “An Italian fellow.”
“You’re going to let Tony take away your mitzvah of ma’akeh?!” asked Mr. Adler.
“I’d love to do it myself,” said Mr. Braun, “but I’ve got two left hands! If I built the ma’akeh myself, I wouldn’t risk using the porch!”
“I understand,” laughed Mr. Adler. “How high will the guardrail be?”
“Tony said that the code in most places in the U.S. is at least 36 inches for a residential guardrail,” replied Mr. Braun. “Some make it higher, 42, or even 52 inches for high porches. What is the required height according to halacha?”
“Halacha requires that the ma’akeh be at least 10 tefachim,” replied Mr. Adler. (C.M. 427:5)
“What is that in inches?” asked Mr. Braun.
“A tefach is at least 3 inches; according to the Chazon Ish almost 4,” replied Mr. Adler. “Rav Moshe Feinstein maintains 3.6 inches, so that 36 inches would be 10 tefachim according to him. Since this is a mitzvah d’oraysa and is to protect from danger, ideally one should adopt the more stringent view of 40 inches.”
“I heard there is a berachah on making a ma’akeh,” said Mr. Adler. “I guess I’ll make it when Tony starts working on it.”
“I’m not sure you can make the berachah on Tony’s work,” replied Mr. Adler
“Why not?” asked Mr. Braun. “I’m making sure there is a ma’akeh on my porch!”
“Yes, but you’re not performing the mitzvah,” said Mr. Adler. “Tony’s doing it.”
“But he’s doing it for me,” said Mr. Adler. “He’s like my agent.”
“A non-Jew can’t be considered an agent in this regard,” said Mr. Adler. “The issue is a bit complex; I suggest you contact Rabbi Dayan.”
Mr. Braun texted Rabbi Dayan: “Can I make a berachah on a ma’akeh made by a non-Jewish worker?”
“It is questionable whether one can make a berachah on a ma’akeh made by a non-Jewish worker,” replied Rabbi Dayan. “If you attach the last required piece, then you can. Please call for further elaboration.”
Mr. Braun called Rabbi Dayan. “Could you elaborate about the ma’akeh?” he asked.
“In general, a person who performs a mitzvah makes a berachah,” explained Rabbi Dayan. “If he performs the mitzvah through an agent, a shaliach, the agent usually makes the berachah. However, a non-Jew cannot serve as an agent.”
“So what’s the question?” asked Mr. Braun. “It seems clear that I can’t.”
“The Machaneh Ephraim [Hil. Sheluchin #11] suggests there is a difference between an agent and an employee,” explained Rabbi Dayan. “The Gemara [B.M. 10a] teaches that even according to the opinion that an agent cannot acquire a lost item [aveidah] for another, an employee can acquire it for his employee. [C.M. 270:3] This is because the hand of the employee is considered as the hand of the employer. Thus, even if a non-Jew cannot serve as an agent for the mitzvah of building the ma’akeh, if he is an employee his actions are attributed to the employer, so the employer can make the berachah.”
“The Machaneh Ephraim suggests a further reason to allow making a berachah,” added Rabbi Dayan. “Although a gentile cannot serve as an agent for a legal issue that requires agency of the sender, such as separating terumah, for a practical matter, such as building a ma’akeh, he can be considered an agent.”