So, it actually took me two more days to finish the roof of our compost bin. Actually, I spent almost all of the second day trying to figure out how to piece all the misshapen scrap wood together into something sturdy and coherently roof-shaped. That, and I was hoping it would rain so I could stay home, but it didn't so I didn't go out until after lunch!
After designing, scraping and redesigning, building, demolishing and rebuilding several version in my mind, I ended up with four rafters and three purlins as the basic structure of the roof. Incidentally, I do not have a ladder nor access to one, so...I built the frame on the ground and then heaved it up, and rested it on the two beams I fixed into place. This was just a dry fit. I left it up over night, and thankfully it was still there the next day!
On the third day I pulled the roof frame off the posts and beams and laid it in front of the bin. I proceeded to attach several half and quarter length purlins to the frame. Rafters support most of the weight of a roof when rested on some kind of beam or support. Purlins are affixed atop the rafters and basically provide rigidity and a place to attach the roof covering.
In this case, I started with one piece of ply-wood and a bunch of mismatched siding planks. I thought of using the ply-wood whole on one side and the planks on the other, but instead I ripped the ply-wood in half with my 100 Yen hand saw and put one half on either side, with the planks in the middle. I hope this is the best design considering any load it may bear under snow in the winter and the shear beating it will take from high winds and hurricanes.
For the final weatherproofing, I nailed and screwed three bent, rusty pieces of sheet metal with all but the last four nails and four screws I owned. I even pulled several dozen rusty nails from the scrap pallets and straightened them out, because I knew I might not have enough.
Next came the fun part...I lifted the roof up and maneuvered it into place. I had arranged for Michie to help me lift it up after she got home from work, but that was hours away and I thought, 'what the heck!? It only weighs about a hundred pounds, and I am young and game, so why not just do it myself!?' So I did. It turns out that the patch-work purlins made excellent hand holds as I stood over the open pit of the bin with a foothold on the front and back pallets. I had propped the roof against the left side and then proceeded to hoist it up a few inches at a time. With the last four nails, I hammered the side rafters to the posts, and with the last four screws connected the beams to the underside of the innermost rafters. I definitely need to buy more hardware whenever we get to the mainland next!
There are a few things left to complete, but for now, the compost bin is fully functional, and has a pile of sukanpo in it already! I still need to dig a bigger trench to hold the buoys for water catchment and I also need to devise a covering for the top of the bin that is both breathable and bird-proof. There is a grove of thin bamboo to the south of our garden, and I think I might try weaving a roll-up screen from that. I have never weaved before, and never really worked with bamboo, so that should be fun...
In retrospect, I probably should not have lifted the roof up all by myself. For that matter, I probably should not have built the roof on the ground first! I suppose I could have built a ladder, but then I wouldn't have had any more wood for the roof. Such are the conundrums one faces when building a driftwood compost bin.