Bunk Bed with Ladder and Trundle by InnovationsOxford Bunk Bed with Ladder and Trundle Innovations solid wood bunks use Mortise and Tenon joinery at all footboard and headboard junctions; they are glued and reinforced with screws for long term stability. This is much stronger than typical doweled joints. Twin over twin bunk beds with OPTIONAL kit to make bottom full size for additional cost.