Building the Octagon Pt.19 Fixing the beams.

Sunday morning and showers have arrived with a delightful drop in temperature. They probably won't last long but they will stop progress for the moment. Keen as I am to refit the beams I ought to hold off until the glue has set. Lots more than anticipated squished out of the joints as I cranked on the nuts. It was runnier than  expected and literally fell off the wood as it squeezed out. I made a bit of a mess scraping the excess around the various cracks in the timber. Just using odd off-cuts of wood which were lying about. The dried glue is off-white and has a slightly rubbery consistency. I haven't tried scraping it yet.

Once the rain cleared I started work on the main beams again. Using my laser rangefinder I double checked the distance between the posts at both floor levels. The hanging cords made it incredibly easy to manage the beams independently without danger or repeated heavy lifting.

First I fixed the inner [mitered] beams to the posts with 4 x 4" screws. There followed the fixing of the outer beams, again using 4 x 4" screws at each end. The doubled beams were well clamped together to ensure a close fit. I shall bolt through both beams and the posts as an extra precaution when I obtain more 12mm/ 1/2" galvanized threaded rod [studding or all-thread.]

The poor man's drone, camera-eye view from a ladder up against the gable end, ridge of my shed.  Beams now well fixed with 8 x 4" screws at each end. I have now used exactly 90 x 4" screws.

The improvement in stiffness of the octagon structure was very obvious in line with the beams. Though it made no real difference perpendicular to them. Only finger tip pressure on the N and S posts is required to make the whole structure sway in and out. Pressing in any direction on the posts, now attached to the beams, produces no movement.

I think I may have to run cross beams between the doubled beams. Then carry them through to the upper rim joists. Except, that the present, 2x6 rim joists are "history." They have to go to make room for the obs. floor joists. The parallel floor joists going on top of the beams would probably stiffen things up in that direction [N-S] but working on a flexible structure makes all measurements rather pointless. It is also feels insecure working on such a swaying structure.

For this image I am indebted to members of Cloudy Nights Forums. The author was kind enough to voluntarily provide drawings for the beam structure and overlay of obs. floor joists. Other members provided unique insights and suggestions for improvements as the plan rapidly progressed to completion. With regular interjections on my part to spread my usual confusion. 

Blue shows the support beams and brown the Obs. floor joists and rim joists lying on top. The nearby shed curtails the potential for a veranda right around the building. So the veranda and balustrade will stop on a line just outside of the two nearest posts to the shed.

Without the freely given assistance of these building experts my project would have been much the poorer and certainly flimsier. Their vast experience allowed them to find a safe and workable solution based on my own, existing, half-built,  octagonal structure. I had rather half-baked plans for radial floor joists emanating from a central [floating!] octagonal ring. [Believe it or not!] The present arrangement is vastly superior to any of my my own ideas. I just hope I have the skill and persistence to complete the project to their own very high standards.

It goes without saying that I am extremely grateful for their kind assistance. Anyone attempting to copy the design [without written authorization] should realise that this was a personal response to my own, personal project. The author[s] of the image[s] and any others involved in its conception cannot possibly supervise anything anyone else might do with the drawing[s] or the design.

Your own work is as limited to your own skills [or complete lack of] and any personal understanding, knowledge [or complete lack] of the problems and safety of any structures or building work involved. Don't blame the messenger[s] for your own handicaps and limitations. Build your own design. You copy this one entirely at your own peril! The authors were full of even better ideas but I desperately wanted to avoid demolition of my existing octagonal structure.  So, basically, I wouldn't recommend you even start from here! 😉

Click on any image for an enlargement.

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