Expert: Bruce E. Johnson - 2/6/2012

Question
Hi Bruce,

 We re in the process of building a new home, and we need to install 2 support posts for a beam on one side of our basement.  The basement floor has not been poured yet, but we did pour (2) 2x2 pads in the locations of the posts when we poured the original footer.  Can you describe the proper procedure for install beam posts in new construction, in detail ?  I've seen pictures with posts installed with threaded adjustments at the top, and some with threaded adjustments at the bottom.  I've seen some with the rectangle plates sitting on and anchored to the concrete floor and I've seen some where the round post seems to just 'disappear' into the concrete floor. I've not been able to find a 'proper procedure' for this in new construction. Please let us know if you can describe one.  Thanks, Brian.

Answer
Hi Brian, I'm not a big fan of "buried" posts especially in basements.  If there is moisture present you may eventually find your buried post bottom rotted away and you wouldn't even know it until it was too late.  So, that being said, you have a lot of other options.  Simpson Strong-tie makes several types of post bases for wood posts.  One style involves an embedded bolt with the threads sticking up above the concrete an inch or so, enough to allow the post base, a washer, and a nut.  Then there is an insert that holds the bottom of the post up above the bolt, the sides of the base then are screwed or nailed into the bottom of the post.  If you are using a steel adjustable post shore with a screw top, the bottom usually has a square base with a hole in each corner through which a tap-con or other form of concrete screw is used to attach the base to the floor.  Generally speaking basement posts don't need a lot of connection at the base because they are in a compressed state since the weight of the house sits on them.  Most house plans will specify the type of column or post required for beam support and show a detail of the connection at the top and the base, the size footing required etc.  these are generally specified by a structural engineer who has calculated the amount of load that will be concentrated in these areas.  I hope this information helps, please feel free to write again regarding this or other matters.  Sincerely Bruce E Johnson..bejohnsonconsulting.com