A sealing device for buildings, comprising a duct and a link member secured to this duct, wherein the duct comprises - a main axial portion, - an intermediate annular portion (4; 204) facing an end annular part (6; 206) of the main axial portion, - a terminal annular portion (5; 205) facing the intermediate annular portion (4; 204), the intermediate annular portion and the terminal annular portion being situated radially one inside the other and linked by an annular fold (8; 208) so as to form an axial annular mounting slit that is open axially opposite this annular fold (8; 208) and the other end of the main axial portion, the intermediate annular portion (4; 204) extending between said end annular part (6; 206) of the main axial portion and the terminal annular portion (5; 205); wherein the link member (10; 210) comprises a radial flange plate (11; 211) and, around a through-opening, an axial annular mounting portion (12; 212), the radial flange plate and the axial annular mounting portion being linked by an annular fold; and wherein the axial annular mounting portion (12; 212) of the link member (10; 210) is engaged axially and gripped radially, over at least one annular zone, in said annular mounting slit between the intermediate annular portion (4; 204) and the terminal annular portion (5; 205) of the duct (2; 202), and wherein said main axial portion, said intermediate annular portion of the duct, said axial annular mounting portion of the link member and said terminal axial portion of the duct have annular ridges (4a, 6a, 5a and 12a) engaged in one another. wherein the duct comprises - a main axial portion, - an intermediate annular portion (4; 204) facing an end annular part (6; 206) of the main axial portion, - a terminal annular portion (5; 205) facing the intermediate annular portion (4; 204), the intermediate annular portion and the terminal annular portion being situated radially one inside the other and linked by an annular fold (8; 208) so as to form an axial annular mounting slit that is open axially opposite this annular fold (8; 208) and the other end of the main axial portion, the intermediate annular portion (4; 204) extending between said end annular part (6; 206) of the main axial portion and the terminal annular portion (5; 205); - a main axial portion, - an intermediate annular portion (4; 204) facing an end annular part (6; 206) of the main axial portion, - a terminal annular portion (5; 205) facing the intermediate annular portion (4; 204), the intermediate annular portion and the terminal annular portion being situated radially one inside the other and linked by an annular fold (8; 208) so as to form an axial annular mounting slit that is open axially opposite this annular fold (8; 208) and the other end of the main axial portion, the intermediate annular portion (4; 204) extending between said end annular part (6; 206) of the main axial portion and the terminal annular portion (5; 205); wherein the link member (10; 210) comprises a radial flange plate (11; 211) and, around a through-opening, an axial annular mounting portion (12; 212), the radial flange plate and the axial annular mounting portion being linked by an annular fold; and wherein the axial annular mounting portion (12; 212) of the link member (10; 210) is engaged axially and gripped radially, over at least one annular zone, in said annular mounting slit between the intermediate annular portion (4; 204) and the terminal annular portion (5; 205) of the duct (2; 202), and wherein said main axial portion, said intermediate annular portion of the duct, said axial annular mounting portion of the link member and said terminal axial portion of the duct have annular ridges (4a, 6a, 5a and 12a) engaged in one another.