To solve the problem that a conventional ridge sill tile is composed of a flat section having the same cross sectional shape as a pantile, an opening section between the rafter and the pole plate erected from the flat section and an extending section projected in approximately parallel with the flat section from the opening section and a dry type ridge can be executed simply but there is the probability of the generation of an opening between the ridge sill tile and the surface of the pantile, the problems of the consistency of mutual roofing and the infiltration of rain and wind from a joint and effective width cannot be adjusted.

A base plain ridge tile with the opening section for a ridge construction method is composed of an upstanding section engaged and fixed to the ridge core material of a roof and a hanging piece, the opening section with an opening-section lower-end curved surface abutted against the surface of the pantile, the base plain ridge tile section on which the plain ridge tile is roofed and the superposing receiving piece of the base plain ridge tile section and a superposing covering zone. The base plain ridge tile with the opening section optimum for an earthquake-resisting and rain-wind-resisting ridge structure is utilized, and the ridge can be constructed surely, simply and rapidly. The constitution of superposition mounted at both side ends extending over the opening section from the base plain ridge tile section of the base plain ridge tile with the opening section fills the role of the prevention of the infiltration of rain and wind and the improvement of a weathering, and effective width is adjusted by using an effective-width adjusting thin side section formed at a joining end as required.