Ok, I made the 10 foot posts today. I made them with 4 1x6 "apperence board" and let me tell you they came out pretty good. for those of you doing this too, a miniture crow bar and 8 or 12" clamps are an absolute must. When going to the store make sure you choose "apperance" board, which has sharp edges and is more flexible than decking wood. more over, inspect every piece you buy. We bought sixteen and inspected everyside by visuals and by placing on flat floor to make sure there was absolutley no warping. Trust me you will thank yourself in the long run. This proved to be a good thing because making them wasn't that big of a deal. First, we put two boards standing on their side and placed wood glue up and down the side. Then placed a board on top and after doing the the first board the hard way, let me tell you a shorter, easier method. when you make the first two screws at one end of the post, push outward the two side boards from the top board at the other end. it is easier to push in rather than "pull out" when it is already underneath. Believe me it makes a difference. Lastly, remember to do one end at a time, this should help keep them more flush while screwing about every foot or foot and half.
NOW, on to my problem. where I am going to put these things. I don't think at all I will have to block them in. The are pretty wide, about 6.4x8 true inches. This makes for a big area and I think two 1/2 bolts 10" should be more than enough support for these goliths? however, I could be wrong and if so, what exactly should I do??? Again, the lag screws are going trough two 2x12 joist boards.
have fun always