E04F—FINISHING WORK ON BUILDINGS, e.g. STAIRS, FLOORS
E04F17/00—Vertical ducts; Channels, e.g. for drainage
E04F17/02—Vertical ducts; Channels, e.g. for drainage for carrying away waste gases, e.g. flue gases; Building elements specially designed therefor, e.g. shaped bricks or sets thereof
Paroi pour la realisation d'elements comportant au moins deux parois formant un diedre et element realise par assemblage de plusieurs parois selon l'invention