In building an elevated deck over 6x6x6 posts, a beam made of 3 pressure treated 2x8x16' (where the beams are attached to each other with FastenMaster ThruLoks) is too narrow (~5" versus 6" expected) for the galvanized-steel beam holder resting atop the post. I suppose this is due to nominal widths of the lumber, but I read this technique was acceptable if you could not get a beam and wanted to build it yourself with 2x8x16' pressure treated lumber. Where did I go wrong and what can I do to keep doing this right?
Getting the right size bracket isn't a problem, if you go to Simpson Strong Tie web site, or other comparable brand, you'll find a part number to fit your beam and post sizes. Look at the PCZ6. Or on this catalog page, the CC4.62-5.50:
Just make sure that the built up beam you made is adequately sized for the load. A built up beam made from three 2x8's may be strong enough for your deck but it is not as strong as a 6x8 beam.