Does My Deck Need Posts?
Set the beams right on the post-base connectors when there's no room for posts—but make sure to use lumber treated for ground contact.
I’m building a freestanding deck with three beams to support the joists. Each beam will be supported by four concrete footings. The total height of decking, beams, joists, and post-base connector only leaves about 7 in. for a post if the pier is flush with grade. I am wondering if I can pour the pier 7 in. above grade and just attach the beams directly to post bases and skip the posts?
—Scott Losi via email
Editorial advisor Mike Guertin replies: This one has an easy answer—yes, you can set the beams right in the post-base connectors that are anchored to the footing/piers. I’ve done this many times. Since the 4×4 post bases are 3-5/8 in. wide and the double 2×8 beams will be a fat 3 in., you can rip pressure- treated filler blocks to fill the remaining space. Use long nails or screws to fasten the connectors to the beams.
Make sure to use UC4A ground-contact-treated lumber for the beams. Many lumberyards stock ground-contact-treated 2x stock now, but double-check to make sure. Above-ground-contact (UC3A) treated lumber is not recommended this close to the ground. Even though the beams won’t be in contact with the soil, they should still be UC4A or better–treated because of their close proximity to it. And it’s a little added insurance, since it’s hard to check the condition of beams close to the ground during the life of the deck once the framing is covered by deck boards.
Drawing: Kate Francis
From Fine Homebuilding #296