A slope adjustable head for an adjustable pedestal (10) for supporting beams, panel members, typically pavers, in accurate edge aligned relation, in a level plane is disclosed. The pedestal (10) includes a base block (12) and a series of inter-engaging threaded annular elements (20, 30) which can be rotated relative to each other to adjust the height of the top of the pedestal in a screw jack fashion. A slope compensator is located at the top of the pedestal and comprises a slope compensation plate (100) and a head member (50). The head member (50) defines a concave surface having a defined radius of curvature. The slope compensation plate (100) defines a corresponding convex surface having the same radius of curvature and sits on top of the head member. The pedestal (10) is calibrated to allow adjustment for typically zero to five percent in one percent increments. The top member defines a central aperture (56) and a series of holes (72) arranged in a spiral around the central aperture. The adjustment member defines a depending central cylindrical portion (110) which locates in the central aperture (56) and two diametrically opposed depending pegs (132, 134) spaced either side of the central cylindrical portion which locate in the holes of the top member. Rotation of the slope compensation plate (100) about its centre of curvature causes the angle of the adjustment plate relative to the vertical axis to change thus allowing for compensation for the slope of the surface on which the pedestal is standing.