Almost all our attention is being placed on flooring spans. The goal of 9m spans is actually harder than it seems. For every extra unit of distance to span the loading is 4x; so the extra 3m has meant some serious engineering to achieve this goal.
We feel we have the answer, and as per recent issues, the solution has improved the system through forcing us to think more laterally.
The solution lies once again with carbon fibre. We recently took out carbon fibre from some of the outer skins as it wasnt needed for the walls. However we will need it for the 9m spans of the ceiling / floor system.
What we have decided is to add unidirectional carboon fibre to the areas that require it only. This will be done manually in the factory using a slightly different method which will also have the added bonus of making the structural skins continuous (better again for stiffness). This will keep costs down - as a 9m span will not be required very often at all.
In the floor plan here, you can see the different colours showing areas of spans.
(lets pretend for a minute that we can only span structurally one way being up and down; as side by side is only 3.7m which doesnt help explain my point).
Most of the house floor system is fine as the spans are all well be low 6.0m (green). However the open plan section (orange) has a span of 9.0m. So for this area ONLY we locally add UD carbon fibre to the area to the top and bottom skin. This could be 2 or 3 or 4 layers of UD carbon until we reach the desired deflection amount. Essentially because of the nature of how carbon / composites work, we could keep going for 10m-12m spans - just the cost would start the escalate.
This 9m span issue really only will ever occur on large luxury homes - very rare for normal custom homes and almost non-existent with town houses or apartments. So we are putting a lot of effort into something not critical to the success of this system.
So this result is good and allows us to maintain a simple system that is now a little more flexible if required.
UPDATE - test pieces are on their way for initial fire / heat test. We hope to get our fingers on them by end of next week. Cant wait.