Sorry if this has already been covered on here, but I couldnt find it.
Building a Walipini with concrete block walls but I need a long lasting material for the roof trusses. I've been asking around and it seems that the more I ask, the more opinions I get. I've heard locust, white oak, hemlock, and finally one fella said to use modern copper treated pine. He said the modern treated is safe, and Google says that as long as it doesnt contact the food directly that its safe. Another source suggests regular pine with a penatrating oil, like tung. Then there's the thing of if I miscount or miscut and have to get one or two boards.
I cant get locust (all crooked), hemlock is 1.10 per board foot, white oak is .80 a board foot. Treated is .45 a foot.
I want to build a good structure, but I just cant spend tons of money. I'm looking at around 600 board foot. Perhaps more.
I'm struggling with the same thing. However my greenhouse is currently going to be 40'x55' so the vertical on the roof is 45' based on the pitch I need. Can't find wood that long without it being manufactured. It was suggested to me to use metal tubing. Not sure the cost for you but just a thought.
Companion Planting Guide by World Permaculture Association