Bamboo Trusses and Purlins
Roof trusses and purlins are normally quite expensive items requiring high-end timber or metal profiles to meet the structural reliability. These components can easily be replaced by low-cost bamboo elements with their high tensile capacity, trimmed to a dimensional standard and combined with an efficient back-to-back gusset joint design. Even a budget for a regular cement-block house could benefit from a low-cost bamboo roof structure.
Steel plate gusset material can be sourced from scrapyards at very low cost. The 2 mm steel plate covering “white goods” like washing machines, refrigerators etc is perfect. That surface has a high-quality corrosion resistant coat and cuts can be bevelled and quickly recoated. If CNC equipment is available cutting can be very efficiently organized for large scale production....
Factory rig: Wood cradle positioning culm
halves and gussets for angles and standard assembly.
Factory work-flow trusses
Drilling guide: Ø mm bit sizes - important!
Ø5, 4, 3 mm. This will avoid cracking the bamboo and makes the lower bamboo act as a nut. Finally let the protruding screw enter a small cube of wood to work as an anvil and allow for powerful tightening.
Ebiobambu, Visconde de Mauá, Brazil Nov 2025
Purlins can be made using the same recomposed bamboo culm halves, hence the same section as for the truss. Mounting the purlins is then simply done by inserting a sufficiently long wood screw. Let it first enter between the purlin halves and then reach through the truss culm halves.
With a common roof pitch of max 27° this method should be enough. For a steeper roof pitch, it might be necessary to support the purlin with a small piece of wood or bamboo also stuck in between the truss culm halves. The center-to-center distance for the purlins is of course a matter of roof cover weight, wind pressure and structural design. 
Roof cover support for metal sheets, roof tiles or fiber-cement shingles.., can also be fixed to the purlins in a similar way.