I think it all good advice. I was thinking on bending 3 half inch strips in lieu of 2 three quarter strips. That would take just a bit more ripping however may bend easier without steaming and stronger because elf the three ply.
I know building a steam box is not that difficult however for production I would prefer cold bending options before steaming if possible.
And yes, the design comes from the Gothic arch of a boat hull so I suppose I may find some good advice there. Was not thinking about that.......
I don't know how important the rot and insect resistance wood will play a factor if the trusses are polyurethaned however no wood will last if the owner does not take care of it and at least recoat it in a few years. It's not the kind of greenhouse you can let sit uncovered for a few years then try and cover it again later. It must be kept up and maintained. Like any wood product it must be taken care of.
The Gothic arch design with plywood gussets is common and will be used for the smaller and wider models. I was just trying to create a design that's all one piece in lieu of two rafters to a ridge with gussets plates. My idea was to make it simp,e to,install and look beautiful. This is just the prototype to work out all the kinks.
The Gothic arch 2 rafter design is less in wood and less bending because the arch stops at the point unlike the one I created which only does this on the top ply's and continues the full arch radius below. That said it is more wood, cause the design to need more ply's to hold it together but leaves more opportunity for design features and allows for a simple DYI install for the average person to put together.
That was my goal coupled with keeping the package under or close to 9 feet when angle set in a trailer for delivery.
All around the 2 arch one ply top and bottom cord strut design is much more simpler and easy to deliver, manufacture and build vs the one I designed. Like most creative people...... We complicate things however its very hard to duplicate by the average homeowner where the Gothic arch simpler 2 rafter design isn't. That said it still takes skill to design and built it to a quality that could be sold retail.
Cost is a factor in my design but there is a balance to beauty, simplicity of build and the production factor of duplicating the build over and over. This is the balance I am trying to find. This is the only model I am able to meet that criteria. All other models will not fit on the road for delivery or are too small to create in one piece, although I may try to create a smaller model than this 16 ft one in one piece. I just like the idea of one piece truss in stead of the two rafter with a ridge design. To a builder or contractor it's not a problem but for a homeowner it just seems simpler to stand them up, put on the bracing and cover it over. Not to mention I can prefab the end walls with the door and end wall framing in place with the 2 rafter model the installer will have to do this and if its the homeowner it could break the deal for the DYI guy or gal.
Buy, stand, brace and cover..... Trying to keep it simple. I am suggesting a standard foundation of 2 to 3 high 6x6 treated timbers mounted to footings with a 4x4 on top to bolt on the trusses. Of course it could also be mounted to a masonry foundation or even a post in a footing for each truss with a 4x4 on top for mounting to ground level though this puts the trusses at dirt level or close that would not be a good idea.
Just tossing around a few ideas because I love the knowledge and experience on the form. It has been so helpful in the past. This has been a passion of mine for some time building these greenhouses and this fall and winter is when I'm going to get things going. I just need to work out all the kinks. Who knows..... Maybe the 16 ft one piece truss won't sell however I am going to try and work it all out because I just love the look and simplicity of the build of a delivered kit package I could develop with this design. In the end it just might not be cost affective.