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We are building a house in Northern California with a wrap around porch. The roof extends out over the porch, where it is supported by 4’X8′ posts every 14′. The posts are 10′ tall and are strapped to the porch deck and supported by blocking below. The blocking rests on the pressure treated sill, which is bolted to the poured concrete foundation, so the posts are 2′ above grade. The 4’X8′ posts will be “wrapped” with decorative permacast round columns. Should we use pressure treated posts and if we don’t what are the risks? Thanks in advance.
Larry
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I presume you meant 4"x8" posts, not 4'x8'. My immediate concern would be warpage with solid posts, as I've seen 4x4 pt posts look like licorice swirls after drying out. Since the posts are being clad, I would think about laminating the inside posts with opposing grain plies. Nothing wrong with pt in this application, and it's one less termite or carpenter ant worry.
*Barry,Absolutely correct, I missed the shift key, the posts are 4"X8" X 10 ft long. If I understand the plies, they would help keep the PT posts from warping? How should the plies be attached, glued and screwed like decking? Would you still use the plies if we don't go PT wood for the posts? Thanks.Larry
*I haven't done this personally, so I could be stepping on it. I've seen fabricated beams made by gluing up individual boards or planks. The grains are reversed with each ply to counteract warping forces. Since this won't be showing, I imagine you could use mechanical fasteners as well. There are enough professional carpenters on this board, that I imagine one of them would have more to offer. The warping can occur with furniture grade wood absorbing outside moisture, so I'd still stick to pressure treated wood.
*Is there any reason that you don't simply use a steel pipe instead of the 4 by 8. Bugs can't eat it and it won't warp and by welding flanges to it you can attach it anyway you wish.Just a thought....