JFM Standard ‘Heavy Duty’ single span tunnels are available in 7m and 9m widths. Tunnels are supplied in various lengths. All structure frames are made from large diameter Galvanised Tubular Steel incorporating straight sides for improved access & air circulation. Customised Structures can be designed wider or taller than standard, for tropical or alpine climates, with composite panel gable walls, reinforced polytarp covers, aluminum cladding rails, concrete dwarf walls, or with snow braces. Composting Tunnels are designed to incorporate aerated floor specifications & Air Handling Equipment, which are determined by the size off the composting room.