641:1

One who constructs a sukkah, whether for himself or for someone else, does not make a blessing upon its construction. Shehecheyanu would be appropriate to be said when one constructs a sukkah for himself, but we rely on the Shehecheyanu that we recite over the cup during Kiddush [on the first night of the holiday]. Rem"a: If one did not eat in the sukkah on the first night, even though he says Shehecheyanu in his house [as part of Kiddush], when he does eat in the sukkah he must say Shehecheyanu over the sukkah. If he said Shehecheyanu at the time of construction of the sukkah, it is sufficient (R"an ch. "Lulav v'Arava").