An improved panel jointing system wherein panels (10, 11) are provided with profiled edge portions comprising tongue formations (12) and recesses (13) which are of complementary shape to the tongues (12), the tongues (12) of one panel being receivable in the recesses (13) of another panel, wherein the profiled edge portions comprise integrally formed projections (15, 16) projecting from the edge surfaces of the tongues (12) and/or from the walls forming the recesses (13), the tongues (12), recesses (13) and projections (15, 16) being shaped and dimensioned so that, when the tongues are received in the recesses, the tongues (12) form a friction fit with the recesses (13), and the opposed facing surfaces of the tongues (12) and the walls of the recesses (13) being spaced apart so as to form a gap (18) of approximately uniform width which extends along the joint between the panels, interrupted by the projections (15, 16), the gap being fillable with adhesive.