DIFF Subgroup
E04D 13/008 Full Title
Special arrangements or devices in connection with roof coverings; Roof drainage (ventilation tiles E04D1/30; ventilation slabs E04D3/40; internal channels E04F17/00)
E04D 13/008 Special arrangements or devices in connection with roof coverings; Roof drainage (ventilation tiles E04D1/30; ventilation slabs E04D3/40; internal channels E04F17/00)