Building the Octagon Pt.12 Adding load bearing beams.

*

My CN advisors are suggesting I attach 4x4 timber brackets to the upright posts to support the doubled 2x8s beams. The upper floor joists would be laid over these beams from the pier clearance hole right out to the veranda perimeter. The existing, upper perimeter joists will be doubled for greater strength. The image shows a beam mock-up using 2x6s. The angles are the same as the outside bevels at 22.5°.

I collected the four lengths of 2x8 beam timber and a load of joist hangers. They had  special hanger screws which I prefer to short, fat nails. Constant hammering draws attention and gets on people's nerves. Rechargeable drills used as Torx screwdrivers are almost silent except for the ratchet clutches. I shall probably need more 2x6 joists material but will see how it goes. The ground floor will need lots more. So I might as well collect a whole load while I'm at the timber merchants.

I was just working my way around, checking levels on the upper joists, when the heat got to me. I started feeling dizzy and had to go indoors to cool off. It is "only" 70F but the sun feels very hot. The baseball cap didn't help and only made me feel even hotter.

The level of one rim joist was completely off so I had to lower it. The "entrance lintel" joist was slightly too long which was making the left post lean. So I've fixed that too. I could see there were alignment problems when I sighted past the posts. They will have to be corrected before I start strengthening the structure with hefty beams.

The image shows a trial bracket of 100x100mm [4"x4"] timber clamped to bring the 45x195mm [2"x8"] beams to the same level [on top] as the perimeter joists. These beams will take much of the load of the floor joists above so need to be well supported. The beams will also add considerable stiffness to the octagon by preventing it from becoming misshapen.

I might miter the bottoms of the 40cm timber brackets to make them look less "obvious." Then I shall bolt them to the upright posts with long coach bolts and probably star washers. These bite into the adjoining timber surfaces to provide a firmer hold against relative movement. I used these washers extensively on all the joint bolts of my shed framing.

Here a batten has been laid on top of the brackets to check their levels across the width of the octagon. Where a flexible length of timber is used for lightness the level should be placed in the center of the material. If it is placed off-center then the level is very probably sitting on an incline and will give a false reading. Exactly the same occurs with a string/line supported bubble level if placed off center between support points. A stiffer length of timber should not suffer the same curve from sagging as a result of gravity if placed on edge. The downside is that it is much heavier to handle repeatedly compared with a much lighter length of batten. Particularly when one is dealing with a length of over 3m or 10'. Leaving a heavy length of timber resting high up has serious safety issues.

Click on any image for an enlargement. 

*