| 摘要 |
<p>In the installation of a skylight hatch or ventilator in the roof of a building it has always been the practise of building the unit completely or partially from metal for strength and so the unit could be flashed in under the roofing material to be leak free. These metal units Do conduct cold or frost from outside to inside. In this invention on the skylight hatch or ventilator is so designed of plastic to derive its strenght from the structure thus being a lighter, cheaper, maintenance and frost free unit (frost free in countries where frost is present and a frost barrier must be considered.)</p> |
