The construction methods used are highly varied: structures in brick masonry, reinforced concrete structures, metal profiles, cladding in imitation stone, stone cladding, ... The underground niches are connected to monuments above ground. There are different types of funerary monuments on top of the galleries: monuments taking up a column of niches, i.e. five cells, monuments taking up two columns, i.e. 10 niches, or large burial vaults connected to important monuments, up to 21 cells (such as the burial vault of the Vaxelaire family).