While we might refer to particular framing parts as posts and beams, that doesn’t always mean a big solid piece of heavy timber. They might be a different animal altogether.
If you’re building a deck, and you need a beam to run between a couple of posts to support the deck joists, you might simply build it up out of 2x material. Three 2×6″s nailed or screwed together make a 4.5″ x 5.5″ beam, for example. Since even great lumber may twist a little, use a lot of fasteners, staggering them from the upper part of the beam to the lower. You may want to fasten two securely together with smaller fasteners, and then add the third piece. Or you may fasten all three at once with larger fasteners.
Engineered built-up beams
If you’re doing a cathedral ceiling, for example, and you don’t care to have an exposed beam, this is an economical and structurally sound alternative to timber. Built out of laminated wood â€“ essentially gigantic lengths of plywood â€“ they’re strong, and they’re also easier to position, since instead of one massive beam, you’re dealing with three or four lighter lengths. They’re heavy, nonetheless. These should be bolted together with the bolts staggered top to bottom.
You can actually have post and beam construction without real “posts” and “beams”. A series of 2×6″ studs nailed together create a post to support a heavier than normal load. For example if a beam’s weight is transferred by a window or door header, you need more than the single king stud usually nailed alongside the trimmer stud. The extra weight could buckle the studs, so you need to build it up. Essentially, you have a post construction with the header “notched’ into the post. The joists under the sole plate should be built up at the post location so as to transfer the load completely to the foundation wall.