A foam core (30, Fig 5) for a composite laminated article having opposite major surfaces 32, 34 each with a network of moulded, typically impressed, grooves 36 therein which forms a diamond grid pattern 38 on each of the aforementioned surfaces. The network of grooves comprises a first set of mutually parallel first grooves 40 and a second set of mutually parallel second grooves 42. First and second grooves 40, 42 are being mutually inclined at an acute angle α (30 degrees) and intersect to form an array of a plurality of diamond shapes there between, with an acute angle 2α between 45 to 80 degrees. A third set of mutually parallel third grooves 44 extends in a longitudinal direction L. Each third groove 44 intersects with a plurality of adjacent intersections of the first and second grooves 40, 42. Foam core (30) further comprising an array of through-holes extending through the thickness of the foam core between the opposite major surfaces 32, 34. The relevant distances x, y, z may have the values in the ranges of 50-150mm, 10-30mm and 20-50mm respectively. Grooves have a depth (d) of 0.5-2.5mm and a width (w) of 0.5-1.5mm. A method of making foam core (30) by pressing a die in to each surface 32, 34 (see fig 7), and of making a laminated article by vacuum infusion of a liquid in to the network of impressed grooves is also disclosed.