Assuming the outdoor patio slabs are not subject to vehicle traffic, they have a damp proof membrane present, they are clean, dry, sound and prepared as detailed in the technical data sheet we can recommend Rust-Oleum 7200 Floorcoat PU.

This is available in many RAL, NCS or BS colours in a satin or gloss finish.

Please note the drying times are stated at 20°c, at this time of year these will be longer and the paint must be kept dry during this time.