This invention concerns an apparatus and method for perforating a beam. The apparatus comprises a main longitudinal support structure to support the beam. A cutting zone is located along the main longitudinal support structure. Controllable translating means translate the beam longitudinally in the cutting zone. A detector detects a presence of the beam in the cutting zone and in response, a router is controllably moved substantially orthogonally and transversally with respect to the beam, while the beam is translated. The combined controlled movement of the router and the beam results in a perforation of the beam following a predetermined perforation pattern.