CPC Subgroup
E04D 1/24 Roofing elements with cavities, e.g. hollow tiles (E04D1/28 takes precedence)
Full Title
Roof covering by making use of tiles, slates, shingles, or other small roofing elements (roofing supports E04D12/00) > Roofing elements with cavities, e.g. hollow tiles (E04D1/28 takes precedence)