Abstract: A modular building panel having an inner frame, an exterior planar surface, an interior planar surface parallel with but separated from the exterior planar surface by the frame, a generally hollow core disposed between the exterior and interior surfaces, a first side with a longitudinally aligned incurvate aperture, a second side parallel to the first side with a lateral projection congruent with the incurvate aperture, the first and second sides being configured to form an interlocking joint when a lateral projection is coupled with an incurvate aperture and one or more weather seals longitudinally disposed along at least a portion of the interlocking joint. The modular panels may be configured as either wall or roofing panel.