So we have a set of arches. Obviously we need a ridge "beam" and that's not all we need. But wait. The ridgepole must be over 4m long, the length of GH2.0. This is all lightweight construction. So we can't just take a big log and drape it over our hard-won arch.
Before I go any further, I know you will spot lots of mistakes and corrections. I think these are extremely valuable. If everything went as you planned it, you would have learned nothing. So I am being really candid with my mistakes. Anyway, I need a very long ridgepole. Over 4m. Fortunately a very long piece of birch was available. Came down two winters ago. Long log, I call it. By using guile, cunning, my Japanese log saw, a very long rope, and the car for power Long Log was snaked out of his lair. Obviously much too heavy. So it had to be split. This was the first time I have tried to split such a long, narrow log. In order to do this with a froe, I would have had to completely rebuild my brake. So wedges it is.
Alas, Long Log has a severe wind in in it. The tree grew spirally, for reasons known only to itself. Further splitting problematic. At the left of my tool collection is my Portuguese Enxó, or one-handed adze; a very useful tool (available from Lee Valley). So I improvised. Use two pieces of alder for a ridge beam. Patch, likewise, poles for the purlins -- lengthwise pieces of wood that tie the thing together. And we have
...a greenhouse frame. In retrospect, we need another set of purlins, as you will see. But not this year. The purlins serve two purposes. One is structural; they tie the frame together. The other is cover support; they keep the cover from sagging. The purlins were pieced together from what odds and ends I had lying about. I must get those tomatoes in the ground! Now! At this point I could resist it no longer. I must see if the cover will go on at all. The cover, of course, is that old Alaska standby, 6 mil "clear" Visqueen, which is at least translucent if far from clear.
And it works! Needs tuning, of course. Also needs some ends. Now you see why I need at least one more purlin. Too much sag at the top. By the way, this construction has not one nail in it. Everything is lashed together. I find that in the Alaska winter, nails pull out. Lashings stay put. Long Log came in very handy. He is holding down the covering, helped by a few stones. I am working on the ends as we post. Stay, as they say, tuned. I want an easily removed cover, because I intend to build another GH just like this one, so I can rotate them; see last posts.
Early summer harvest
2 months ago