Initial calculations were based on a very basic model / formula. The engineer has since created a more complex (realistic) formula which has exposed some critical issues.
The walls are still excellent.
The ceilings we have issues. The strength is still excellent and we can still span more than 9m, however deflection (sagging) which is critical is not good. This came about after the composite engineer liaised with the structural engineer (residential) and the addition of 'dead loads' and 'live loads' was injected into the equation.
The issues came about even after factoring in the doubled up panels for the floor system (220mm thick combined).
Once again a better system resulted from this flaw and the issue was resolved very quick.
The main issue is the depth of each panel being 110mm. Just by coincidence a different issue was identified same day being the plumbing pipes in the floor needing more than 110mm to be installed properly.
The solution is 2 different types of panels to be used for the floor system:
110mm for the ceiling
190mm for the floor
330mm combined - this is industry standard which is good.
So this change in floor depth (meaning deeper carbon fibre beams) along with a tweak in the carbon fibre beam spacing is all it took. But now we also have 170mm (190mm minus 20mm of external skins) cavity to install plumbing pipes and heating ducts. So this is a good outcome that has solved 2 issues.
Only a very small change in cost.