| 摘要 |
The roof vent comprises a lead sheet 4 with a circular hole or aperture in its centre and a pipe 5 extending below the sheet and through the hole. The hole is covered by a protruding portion 1 that extends raised above the sheet and includes a galvanised steel mesh 3 or grille to prevent vermin or birds entering through the vent. The mesh is secured to the protruding portion by another piece of lead 2. The vent may be used on shingle roofs or on clay tiles. The pipe may be flexible or be made from lead. The vent may be used with an extraction fan to enhance flow. |
